Efficacy of Four Systemic Insecticides

Home , Aphytis mytilaspidis, Asterolecaniidae, Asterolecanium, Cadra figulilella, Chilocorus orbus

Efficacy of four systemic insecticides against the green pit scale insect (Palmapsis phoenicis Ramachandra Rao) (Homoptera: Asterolecaniidae) infesting date palm in Northern Sudan

By MAHDI ABDELRHMAN AHMED MOHAMED B.Sc. (Agric.), University of Zagazig, Egypt, 1988 M. Sc. (Agric.), University of Khartoum, Sudan, 1998

A thesis Submitted to the University of Khartoum in fulfillment for the requirements of the degree of Doctor of Philosophy (Ph.D)

MainSupervisor: Dr. Azhari Omer Abdelbagi Co-Supervisor: Dr. Hamadttu Abd Elfarag ELshafie

Department of Crop Protection Faculty of Agriculture University of Khartoum

December 2008

ﻭﺟﻌﻠﹾﻨﺎ ﻓﻴﻬﺎ ﺟ ﻨ ﺎ ﺕ ﻣ ﻦ ﻧ ﺨ ﻴ ﻞﹴ ﻭ ﺃﹶ ﻋ ﻨ ﺎ ﺏﹴ ﻭﻓﹶﺠﺮﻧﺎ ﻓﻴﻬﺎ ﻣ ﻦ ﺍ ﻟﹾ ﻌ ﻴ ﻮ ﻥ ﻟ ﻴ ﺄﹾ ﻛﹸ ﻠﹸ ﻮ ﺍ ﻣ ﻦ ﺛﹶ ﻤ ﺮﹺ ﻩ ﻭﻣﺎ ﻋ ﻤ ﻠﹶ ﺘ ﻪ ﺃﹶ ﻳ ﺪ ﻳ ﻬﹺ ﻢ ﺃﹶﻓﹶﻼ ﻳ ﺸ ﻜﹸ ﺮ ﻭ ﻥﹶ

ﺳﻮرة ﻳﺲ اﻵﻳﺎت ﻣﻦ ٣٤-٣٥

Efficacy of four systemic insecticides against the green pit scale insect (Palmapsis phoenicis Ramachandra Rao) (Homoptera: Asterolecaniidae) infesting date palm in Northern Sudan

MAHDI ABDELRHMAN AHMED MOHAMED

ﻣﺴﺘﻠﺨﺺ اﻻﻃﺮوﺣﺔ

ﺗﻢ اﺟﺮاء ﺳﻠﺴﻠﻪ ﻣﻦ اﻟﺘﺠﺎرب اﻟﺤﻘﻠﻴﺔ اﻟﻤﺼﻐﺮة ﺑﻤﺸﺮوع اﻟﻐﺎﺑﺔ اﻟﺰراﻋﻲ وﻣﻨﻄﻘﺔ اﻟﻘﻮﻟﺪ ﺧﻼل ﻣﻮﺳﻤﻲ 2003/2004-2004 /2005 ﺑﻬﺪف ﺗﻘﻮﻳﻢ ﻓﻌﺎﻟﻴﺔ أرﺑﻌﺔ ﻣﺒﻴﺪات ﺟﻬﺎزﻳﺔ ،اﻣﻴﺪاآﻠﻮﺑﺮﻳﺪ ﻓﻰ هﻴﺌﺔ (Rinfidor 20%SL, Confidor 200SL وComodor 20%SL) وﺛﻴﺎﻣﻴﺜﻮآﺜﺎم ﻓﻲ هﻴﺌﺔ (Actara 25WG) ﺿﺪ ﺣﺸﺮة اﻟﻨﺨﻴﻞ اﻟﻘﺸﺮﻳﺔ اﻟﺨﻀﺮاء اﻟﺤﺎﻓﺮة (Palmapsis phoenicis Ramachandra Rao) ﺑﻤﺸﺮوع اﻟﻐﺎﺑﺔ اﻟﺰراﻋﻲ وﻣﻨﻄﻘﺔ اﻟﻘﻮﻟﺪ وذﻟﻚ ﺑﺎﺳﺘﺨﺪام ﻃﺮﻳﻘﺘﻴﻦ ﻟﻠﻤﻌﺎﻣﻠﺔ ( ﻣﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﺔ و ﺣﻘﻦ اﻟﻤﺒﻴﺪ ﻓﻲ ﺳﺎق اﻟﻨﺨﻠﺔ ).أﺳﺘﻬﺪﻓﺖ اﻟﺘﺠﺎرب ﺗﺤﺪﻳﺪ اﻟﺠﺮﻋﺔ اﻟﻔﻌﺎﻟﺔ وﻓﺘﺮة ﺛﺒﺎت هﺬﻩ اﻟﻤﺒﻴﺪات (Persistence) وآﺬﻟﻚ اﻷﺛﺮ اﻟﻤﺘﺒﻘﻲ ﻋﻠﻲ اﻟﺜﻤﺎر واﻟﺘﺮﺑﺔ واﻟﺰراﻋﺎت اﻟﺒﻴﻨﻴﺔ.

أﺳﺘﺨﺪﻣﺖ اﻟﺠﺮﻋﺎت ﺻﻔﺮ، 20، 25 و35 ﻣﻞ\ﻟﻠﻨﺨﻠﺔ و 10 ,15 و20 ﻣﻞ /ﻟﻠﻨﺨﻠﺔ ﻣﻦ ﻣﺒﻴﺪات ( Rinfidor 20%SL و Comodor 20%SL ) ﻟﻤﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﺔ واﻟﺤﻘﻦ ﻋﻠﻲ اﻟﺘﺮﺗﻴﺐ . اﻣﺎ ﻣﺒﻴﺪ Actara 25WG ﻓﻜﺎﻧﺖ ﺟﺮﻋﺎﺗﻪ هﻲ9, 12, 15 و18 ﺟﺮام /ﻟﻠﻨﺨﻠﺔ و 6 ,8 و10 ﺟﺮام /ﻟﻠﻨﺨﻠﺔ ﻟﻄﺮﻳﻘﺘﻲ ﻣﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﺔ واﻟﺤﻘﻦ ﻋﻠﻲ اﻟﺘﺮﺗﻴﺐ اﻣﺎ ﻣﺒﻴﺪ آﻮﻧﻔﻴﺪور Confidor 200 SL اﺳﺘﺨﺪم ﺑﺎﻟﺠﺮﻋﺔ 35 ﻣﻞ /ﻟﻠﻨﺨﻠﺔ آﻤﺒﻴﺪ ﻗﻴﺎﺳﻲ ﻓﻲ ﻃﺮﻳﻘﺔ ﻣﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﻪ و ﺑﺎﻟﺠﺮﻋﺎت 10 ,15 و20 ﻣﻞ /ﻟﻠﻨﺨﻠﺔ ﻓﻲ ﻣﻌﺎﻣﻠﺔ اﻟﺤﻘﻦ. ﺗﻢ ﺗﺨﻔﻴﻒ ﺟﺮﻋﺎت اﻟﻤﺒﻴﺪات (ﻣﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﺔ ) ﻓﻲ (8) ﻟﺘﺮ ﻣﺎء ووزﻋﺖ ﺑﺎﻧﺘﻈﺎم ﺣﻮل ﺟﺬع اﻟﻨﺨﻠﺔ ﺑﻌﺪ أﺟﺮاء ﻋﻤﻠﻴﺎت اﻟﺘﺤﻮﻳﺾ (ﺑﻘﻄﺮ 3م) واﻟﺘﻘﻠﻴﻢ ﺛﻢ اﻟﺮى ﺑﺎﻧﺘﻈﺎم آﻞ (10) أﻳﺎم. اﺳﺘﺨﺪم اﻟﻨﻈﺎم اﻟﻌﺸﻮاﺋﻲ آﺎﻣﻞ اﻟﻘﻄﺎﻋﺎت ﺑﻌﺪد ارﺑﻌﺔ ﻣﻜﺮرات (ﺳﺘﻪ ﻧﺨﻼت ﺗﻤﺜﻞ آﻞ ﻣﻜﺮر). ﺗﻢ ﺗﻌﺪاد آﻞ اﻻﻃﻮار اﻟﺤﺸﺮﻳﺔ ( ﺳﻢ2 /ورﻳﻘﺔ) ﻓﻲ ﺛﻤﺎﻧﻴﺔ ورﻳﻘﺎت ﻣﻦ آﻞ ﻧﺨﻠﺔ ﺑﻌﺪ آﻞ اﺳﺒﻮﻋﻴﻦ ﻣﻦ ﺑﺪاﻳﺔ اﻟﻤﻌﺎﻣﻠﺔ. آﺬﻟﻚ ﺗﻤﺖ دراﺳﺔ اﻗﺘﺼﺎدﻳﺔ ﻃﺮﻳﻘﺔ اﻟﻤﻜﺎﻓﺤﺔ .ﺗﻢ ﺗﻘﻮﻳﻢ ﻗﺎﺑﻠﻴﺔ ﺑﻌﺾ اﻻﺻﻨﺎف ﻟﻼﺻﺎﺑﺔ آﻤﺎ ﺗﻢ ﻣﺴﺢ ﻟﻼﻋﺪاء اﻟﺤﻴﻮﻳﺔ.

أﻇﻬﺮت ﻧﺘﺎﺋﺞ ﻓﺤﺺ ﻋﻴﻨﺎت اﻟﺠﺮﻳﺪ اﻟﻤﺄﺧﻮذة آﻞ أﺳﺒﻮﻋﻴﻦ واﻟﺘﻲ ﺗﻢ ﻓﺤﺼﻬﺎ ﺗﺤﺖ اﻟﻤﺠﻬﺮ ، أن أﻋﺪاد اﻟﺤﺸﺮات اﻟﻤﻴﺘﺔ (إﻧﺎث ﺑﺎﻟﻐﺔ + أﻃﻮار ﻏﻴﺮ ﺑﺎﻟﻐﺔ ) ﻟﻜﻞ( ﺳﻢ)2/ ﻟﻠﻮرﻳﻘﺔ زاد زﻳﺎدﻩ واﺿﺤﺔ ﻓﻲ ﻧﺴﺒﺔ اﻟﻤﻮت ﻓﻲ آﻞ اﻟﻤﻌﺎﻣﻼت ﻣﻘﺎرﻧﺔ ﺑﺎﻟﺸﺎهﺪ وﻗﺪ وﺻﻠﺖ أﻋﻠﻲ ﻣﻌﺪﻻﺗﻬﺎ ﺑﻌﺪ أﺳﺒﻮﻋﻴﻦ ﻣﻦ اﻟﻤﻌﺎﻣﻠﺔ واﻧﺨﻔﻀﺖ ﺗﺪرﻳﺠﻴﺂ ﺑﻌﺪ ذﻟﻚ ﺣﺘﻲ ﺗﺴﺎوت ﺟﻤﻴﻊ اﻟﻤﻌﺎﻣﻼت ﺑﻌﺪ ﻣﻀﻲ (12) أﺳﺒﻮع ﻣﻦ اﻟﻤﻌﺎﻣﻠﺔ . وﻗﺪ اﻋﻄﺖ اﻟﺠﺮﻋﺎت اﻟﻌﺎﻟﻴﺔ ﻣﻦ اﻟﻤﺒﻴﺪات اﻟﻤﺨﺘﺒﺮة ﻓﻌﺎﻟﻴﺔ ﻋﺎﻟﻴﺔ ﺿﺪ اﻟﺤﺸﺮة اﻟﻤﺴﺘﻬﺪﻓﻪ

ﻟﻮﺣﻆ أن اﻟﻨﺨﻴﻞ اﻟﻤﻌﺎﻣﻞ ﺑﺎﻟﻤﺒﻴﺪات ﺗﺤﺖ اﻻﺧﺘﺒﺎر ﻗﺪ أﺳﺘﻌﺎد ﻧﻤﻮﻩ وﺗﺤﻮل ﺳﻌﻔﻪ (ﺟﺮﻳﺪﻩ) إﻟﻰ اﻟﻠﻮن اﻷﺧﻀﺮ اﻟﻄﺒﻴﻌﻲ وﻗﺪ ازداد اﻻﺧﻀﺮار آﻠﻤﺎ أﺗﺠﻬﻨﺎ اﻟﻲ ﻗﻠﺐ اﻟﻨﺨﻠﺔ آﻤﺎ ان اﻟﺘﻤﻮر ﻧﻀﺠﺖ ﻃﺒﻴﻌﻴﺎ ﺣﻴﺚ أﻋﻄﺖ اﻟﺠﺮﻋﺔ اﻟﻌﺎﻟﻴﺔ ﻣﻦ اﻟﻤﺒﻴﺪات زﻳﺎدة ﻓﻲ اﻻﻧﺘﺎﺟﻴﺔ وﺻﻠﺖ ﻻآﺜﺮ 70% ﻣﻘﺎرﻧﺔ ﺑﺎﻟﺸﺎهﺪ . آﺬﻟﻚ ﻟﻢ ﻳﺘﻢ اﻟﻜﺸﻒ ﻋﻦ وﺟﻮد أي أﺛﺮ ﻣﺘﺒﻘﻲ ﻋﻠﻲ اﻟﺜﻤﺎر اﻟﻤﺄﺧﻮذة ﻟﻠﺘﺤﻠﻴﻞ ﻓﻲ ﻣﺮﺣﻠﺘﻲ اﻟﺮﻃﺐ واﻟﺘﻤﺮ وآﺬﻟﻚ ﻓﻲ اﻟﺘﺮﺑﺔ واﻟﺰراﻋﺎت اﻟﺒﻴﻨﻴﺔ آﻤﺎ ﻟﻮﺣﻆ ﺗﻮﻗﻒ ﻧﺸﺎط ﺁﻓﺔ اﻷرﺿﺔ واﻟﻨﻤﻞ اﻷﺣﻤﺮ. اﻇﻬﺮت ﻧﺘﺎﺋﺞ اﻟﺘﺤﻠﻴﻞ اﻻﻗﺘﺼﺎدي رﺑﺤﻴﺔ ﻃﺮﻳﻘﺔ اﻟﻤﻜﺎﻓﺤﻪ هﺬﻩ ﺣﻴﺚ آﺎن اﻟﻨﺎﺗﺞ اﻟﺤﺪي اﻟﺤﺮج (M.R.R) 364 % ﻟﻠﻤﻜﺎﻓﺤﺔ ﺑﻤﺒﻴﺪات اﻣﻴﺪاآﻠﻮﺑﺮﻳﺪ. أﻇﻬﺮت ﻧﺘﺎﺋﺞ ﻣﺴﺢ اﻻﻋﺪاء اﻟﺤﻴﻮﻳﺔ وﺟﻮد ﻣﻔﺘﺮﺳﻴﻦ ﻣﻦ اﻟﺨﻨﺎﻓﺲ ﻣﺮﺗﺒﻄﻴﻦ ﺑﺘﻮاﺟﺪ اﻻﻓﺔ . اوﺿﺤﺖ دراﺳﺔ ﻗﺎﺑﻠﻴﺔ ارﺑﻌﺔ اﺻﻨﺎف ﻟﻠﻼﺻﺎﺑﺔ ان اﻟﺼﻨﻒ ﻗﻨﺪﻳﻠﺔ ﻗﺪ اﻇﻬﺮ ﻗﺎﺑﻠﻴﺔ آﺒﺮى ﻟﻼﺻﺎﺑﺔ ﺑﻴﻨﻤﺎ اﻟﺼﻨﻒ ودﻟﻘﺎي آﺎن اﻗﻞ اﻻﺻﻨﺎف ﺗﺎﺛﺮا ﺑﺎﻻﺻﺎﺑﺔ .

Efficacy of four systemic insecticides against the green pit scale insect (Palmapsis phoenicis Ramachandra Rao) (Homoptera: Asterolecaniidae) infesting date palm in Northern Sudan

MAHDI ABDELRHMAN AHMED MOHAMED

ABSTRACT A series of small scale field experiments were carried out in Elgaba scheme, and El Golid area during seasons, (2003/2004- 2004/2005) to evaluate the efficacy of four systemic insecticides; imidacloprid as Confidor 200SL, Rinfidor 20%SL and Comodor 20% SL and thiamethoxam as Actara 25WG, against the green pit scale insect (Palmapsis phoenicis Ramachandra Rao). Two methods of application, soil application and trunk injection were used. The insecticide thiamethoxam as Actara 25WG was tested at 9, 12, 15 and 18g /palm and 6, 8 and 10g/palm for soil application and trunk injection, respectively. While imidacloprid as Rinfidor 20% SL and Comodor 20% SL was tested at 20, 25 and 35 ml/palm and 10, 15 and 20 ml/palm for soil application and trunk injection, respectively. Confidor 200SL (imidacloprid) was used as standard (35ml/palm) for soil application and 10, 15 and 20 ml /palm for trunk injection The specific dose was diluted with eight liter of water in a container and drenched around the date palm tree (3m id) and then irrigation scheduled every 10 days . The Completely Randomized Design with six replicates (one palm = replicate) was used. The insects (all developing stages) were counted (cm2/leaflet). Eight leaflets from each palm were inspected at biweekly intervals. Dates yield and quality were determined at harvest. Residue analysis was carried out on dates, soil and intercropped plants twice (at rutab stage and harvesting). The economics of control using this method were studied .Varietal susceptibility and expected natural enemies were also investigated. Results indicated that the % mortality (adult and immature stages) were significantly higher in insecticides treatments than the untreated control by the two application methods. Results of residue analysis indicated that, no residues of both imidacloprid and thiamethoxam were detected in dates, soil and intercropped plants when treated with the high doses. The higher doses remained effective throughout the experimental period. Date palm treated with the higher doses of tested insecticides, developed normally and the dates reached maturity (ripening) and the yield was increased by more than 70% compared with the untreated control. All insecticides checked termites and many other pests, but did not affect mites. The two methods of application were found highly economical and safe for the users with minimal environmental impacts. Partial budget analysis indicated the profitability of the two packages as indicated by the marginal rate of returns of 364 % for imidacloprid. Survey of the natural enemies recorded two beetles associated with the pest. Among the four varieties tested Gondiella was the most susceptible variety while the least susceptible variety was Wad laggi.

To the soul of my parents,

To my lovely Children Mohammed and Alaa

To my Brothers, Sisters, and Haj Elagib Family

To my Wife, with love

ACKNOWLEDGEMENTS My full praise to Allah for enabling me to complete my study. This is a real blessing from Him and thanks to Him in the way that suits His supreme greatness, will and power. Blessings and peace from Allah to be upon our prophet Mohammed and all his Family and companions. My sincere appreciations go to my supervisor, Associate professor Dr. Azhari Omer Abdelbagi, who was a great source of inspiration and encouragement throughout the period of my study. Also I would like to express my deepest gratitude to him for his systematic guidance, advice, patience, constructive criticisms and continuous supervision until the completion of the study. Iam also indebted to my co-supervisor, Associate professor Dr . Hamadttu Abd Elfarag ELshafie, for his valuable contributions and suggestions that added interesting new knowledge and validity to this study. All his contributions are truly appreciated. I would like to express my deepest thanks to the Agricultural Research Corporation (ARC), especially its chairman and the staff of the Crop Protection Research Center, especially professor Dr. Gaafar Elzorgani,Dr. Alamin M. Alamin, Dr.Hassan O.Kanan, Dr. Ehissan Abbas And Ms. Rawda Elhabieb for the extensive assistance offered throughout the duration of my study and for residues analysis. Thanks also go to Date Palm Research Center of King Faisal University, Kingdom of Saudi Arabia (K.S.A), especially Professor Salah Bin Alied ,Professor Jameel Al khairi and Dr. Abdelgadir Assalam

ii and Professor Nabil Hammid Basher of Gazira University for their kind cooperation and advice during the study. Also I would like to express my deepest thanks to my colleagues Rasheed Fagerri,Abdelrheem Hussien, Dr. Eltaeb M. Abdel Gadir, Dr. Errneo Blassio, Mr. Solom S. Kumodan, Levi Yassin , Mohamed Elshiek, Nazar Khaliel, Nagmeldeen A. Nouri, and the staff of Dongola Research Station and to the Departments of Technology Transefer and Extension and Plant Protection Directorate (PPD) of Ministriy of Agriculture , Animal Wealth and Irrigation , Northern State and to the people of Elgaba ,El Golid and Old Dongola for their appreciated contributions when conducting my study. Special thanks to Abdelrheem Benawi, Shiek Makkawi Habeeb, Abderhaman Mergani and Shiek Elkair Mohamed, Shiek Mahdi Mohi Eldin, Shiek Abbdalla Mohi Eldin and Mahdi Salah,Mohamed Essa and Osman Elkhabier. I would like to express my special thanks, deepest appreciation and gratitude to my dear wife Siham Mohamed Yosif for her whole hearted assistance and sacrifice throughout this study. Her patience and encouragement always remained as my inspiration to complete this degree. Finally, I owe thanks to my brothers, sisters, Haj Alagib Family and all Gissmalab for their spiritual and moral support. Financial support by National Training Center and chemicals provided by chemical companies (Bayer, Syngenta, Green Deel and Riham) is appreciated.

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TABLE OF CONTENTS

Page

DEDICATION………………………..…………………………………… i

ACKNOWLEDGMENTS………………..……………………………….. ii

TABLE OF CONTENTS………………………………………………….. iv

LIST OF TABLES…………………………………………….…………… vii

LIST OF FIGURES………………………………….……………………. ix

ARABIC ABSTRACT……………………………………………………. x

ENGLISH ABSTRACT……………………………………..…………… xi 1: INTRODUCTION …………………………………………………... 1

2: LITERATURE REVIEW…………..…………………………………… 4

2.1 The date palm tree ………………………………………………….. 4 2.1.1 Economic importance……………………………………………….. 4 2.1.2 Origin of date palm………………….………………….……………. 5 2.1.3 Geographical distribution of date palm………..……….……………. 6 2.1.4 Botanical and Morphological Description…………………………… 8 2.1.4.1 Root system……………………………………………………….. 8 2.1.4.2 Trunk………………..……………………………………………. 11 2.1.4.3 Leaves…………………………………….……………………….. 11 2.1.4.4 Fiber, spines and leaflets…………………………………………… 13 2.1.4.5 Reproductive organs……………………………...………………... 13 2.1.4.6 Inflorescences/Flowers…………………………….……………… 13 2.1.4.7 Fruit………………………………………………………………… 14 2.1.4.8 Seed…………………………………………………..…………….. 14 2.1.4.9 Variety description…………………………………………………. 14 2.1.5 Cultural practices (Irrigation, Fertilization, Pollination, Bunch Management and Fruit thinning) ………………………………….. 16 2.2 Scale insects as major insect pests of date palm……………………….. 18 2.2.1 The date palm green pit scale insect…………………………………. 22 2.2.1.1 Signs and symptoms of damages…………………………………... 22 2. 2.1.2 Classification………………………….…………………………… 22 iv 2. 2.1.3 Morphology……………………………………………………… 25 2. 2.1.4 Ecology, Biology and Population Density………………………… 27 2. 2.1.5 Geographical distribution……………………………………….. 29 2. 2.1.6 Host plants and economic importance……….………………… 30 2. 2.1.7 Life cycle…………...……………………………..………………. 30 2. 2.1.8 Management of pest…………...……………………….…………. 32 2. 2.1.8.1 Cultural control………………………….…………………….. 32 2. 2.1.8.2 Chemical control………………………..……………………… 32 2.2.1.8.3 Soil application with Neonictonoids insecticides (Thiamethoxam and imidacloprid)……………………………………………………. 36 2.2.1.8.4 Trunk injection…………………………………………………… 49 2. 2.1. 8.5 Biological control…………………….……………………….. 41 2. 2.1.9 The situation of the green pit scale insect in Sudan………………. 42 2. 2.1.10 Varietal susceptibility……………………………………………. 43 2.2.2 White date palm scale……………………………………………… 44 2.2.3 Red scale…………………………………………………………… 46 2.3 Other major insect pests of date palm………………………………….. 48 2.3.1 Caroub moth………………………………………………………….. 48 2.3.2Rhinoceros beetle (Oryctes rhinoceros Linné)……………………….. 48 2.3.3 Red palm weevil …………………………………………………….. 49 2.3.4 Desert Locust (Schistocerca gregaria Forskal)……………………… 50 2.3.5 Termites (Odontotermis smeathmani)……………………………….. 50 2.3.5.1 Termites Control…………………………………………………… 51 2.3.5.2 Termite’s natural enemies……………………………………….. 51 2.3. 6 Store Pests…………………………………………………………… 51 2. 3. 7 Greater Date Moth (Arenipses sabella Hampsim) …………………. 52 2.3.8 Minor insect pests of date palm ……………………………………... 52 2.4 Other pests of date palm……………………………………………… 52 2.4 .1 Bou Faroua (Old World date mite)………………………………….. 52 2.4 .2 Nematodes………………………………………………………….. 53 2.5 Diseases of date palm…………………………………………………. 54 3 MATERIALS AND METHODS……………………………...... 57 3.1 Chemical control. …………………………………………………... 57 3.1.1Soil application method……………………………………………... 58 3.1. 1.1Season 2003 /2004 ……………………………………………...... 58 3.1.1.2 Season 2004 / 2005………………………………………………… 60 3.1.1.3 Insects count ……………………………………………………... 60 3.1.1.4 Yield and yield components………………………………………. 61 3.1.2 Trunk injection technique…………………………………………… 61 3.1.3 Residue analysis of the tested compounds…………………………… 64 3.1.3.1 Residues of thiamethoxam as Actara 25 % WG in Date palms……. 64 3.1.3.2 Residues of imidacloprid as Confidor 200SL, Rinfidor 20% SL, and Comodor 20%SL in date palms.………………………………... 65

v 3.2 Economic feasibility of controlling the green pit scale insect with imidacloprid as Confidor 200SL…………………………………….. 66 3.3 Varietal susceptibility... ……………………………………………….. 67

3.4 Natural enemies associated with the green pit scale insect in Northern State, Sudan ………………………………………………………… 67 4: RESULTS ………………………………………………………………. 68 4.1 Soil application method ……………………………………………….. 68 4.1.1 Insects count…………………………………………………………. 68 4.1.1.1 Season 2003 / 2004………………………………………………… 68 4.1.1.2 Season 2004 / 2005………………………………………………… 71 4.1.2 Yield and yield components………………………………………….. 71 4.1.2.1 Season 2003 / 2004………………………………….……………... 71 4.1.2.2 Season 2004 / 2005………………………………………………… 76 4.2 Trunk injection method ………………………………………………. 76 4.2.1Insects count ………………………………………………………...... 76 4.2.2 Yield and yield components………………………………………….. 78 4.3 Results of residue analysis……………………………………………... 78 4.4 Economic feasibility of controlling the green pit scale insect with imidacloprid as Confidor 200SL……………………………………. 86 4.5 Varietal susceptibility …………………………………………………. 86

4.6 Natural enemies’ associated with the green pit scale insect in the Northern, Sudan…………………………………………...... 88 5: DISCUSSION…………………………………………………………… 94 5.1 The date palm tree……………………………………………………… 94 5.2 Control measures………………………………………………………. 94 5.2.1 Soil application method……………………………………………… 95 5.2.2 Trunk injection method………………………………………………. 98 5.2.3 Residues analysis of the tested compounds………………………….. 102 5.3 Economic feasibility of controlling the green pit scale insect with imidacloprid as Confidor 200SL……………………………………. 104 5.4 Varietal susceptibility………………………………………………….. 105 5.5 Natural enemies’ associated with the green pit scale insect in the Northern State, Sudan………………………………………………. 106

6: CONCLUSION AND RECOMENDATION S…………………………. 108

REFERENCES……………………………….…………………………….. 110

LIST OF TABLES

Table number Page No.

Table (1): Date palm diseases and their occurrence Sudan ………………… 56 Table (2): Mean biweekly of mortality of adult females and immature stages of green pit scale insect from trees treated with different insecticides ( using soil application method) at Elgaba scheme, season 2003/2004.……………………………………………………………. 69 Table (3): Mean biweekly percentage mortality of adult females and immature stages of green pit scale insect from trees treated with different insecticides ( using soil application method) at Elgaba Scheme,season 2003/2004…………………………………………… 70 Table (4): Mean biweekly mortality of adult females and immature stages o green pit scale insect from trees treated with different insecticides (using soil application method) at ELGolid, season 2004/2005. ……… 72 Table (5): Mean biweekly percentage mortality of adult females of green pit scale insect from trees treated with different insecticides( using soil application method)(Location1and 2)atElGolid,2004/2005…………… 73 Table (6): Mean biweekly percentage mortality of immature stages of green pit scale insect from trees treated with different insecticides (using soil application method) at El Golid,2004/2005(Location 1 and 2)……….. 74 Table (7): Yield and yield components of date fruits from trees treated with different insecticides (using soil application method) at Elgaba scheme, Season 2003/2004……………………………………………. 75 Table (8): Yield and yield components of date fruits from trees treated with different insecticides (using soil application method) at El Golid, season 2004/2005 (Location 1 and 2).…………………...... 77

Table (9): Mean biweekly mortality of adult females and immature stages of green pit scale insect using different insecticides (using trunk injection at Elgaba scheme season 2003/2004…………………………………... 79 Table (10): Mean biweekly percentage mortality of adult females and immature stages of green pit scale insect using different insecticides ( using trunk injection) at El gaba scheme season 2003/2004………… 80 Table (11): Mean biweekly total mortality of green pit scale insect from trees treated with different insecticides (trunk injection) at El Golid, season 2004/2005…………………………………………………….. 81

vii Table (12): Mean biweekly percentage of adult females of green pit scale insect from trees treated with different insecticides (using trunk injection method) at El Golid, season 2004/2005……………………... 82

Table (13): Mean biweekly percentage mortality of immature stages of green pit scale insect from trees treated with different insecticides ( using trunk injection) at El Golid, season 2004/2005 ……………… 83

Table (14): Yield and yield components of date fruits (using trunk injection) at Elgaba scheme. Season 2003/2004…………………………………. 84 Table (15): Yield and yield components on date fruits treated with different insecticides (using trunk injection) at El Golid, season, and2004/2005. 85 Table (16): Economic analysis using imidaclorid as confidor 200 SL to control the green scale insect in the Northern State (Based on survey conducted in 2007) ……………………………………………. 87

viii

LIST OF FIGURES Page No. Fig.1: Mean number of Cybocephalus dudichi on four date palm varieties (with and without intercropping) ElGolid, Baja and Elgaba……………... 89 Fig.2: Mean number of Pharocymnus numidicus on four date palm varieties (with and without intercropping) ElGolid, Baja and Elgaba……………... 90 Fig.3: Mean number of the living adults of the green pit scale insect on four date palm varieties with and without intercropping at ElGolid, Baja and Elgaba area………………………………………………………….. 91 Fig.4: Mean number of the dead adults of the green pit scale insect on four date palm varieties (with and without intercropping) at El Golid, Baja and Elgaba area…………………………………………………… 92

اﻟﻤﺴﺘﻠﺨﺺ

ﺗﻢ اﺟﺮاء ﺳﻠﺴﻠﻪ ﻣﻦ اﻟﺘﺠﺎرب اﻟﺤﻘﻠﻴﺔ اﻟﻤﺼﻐﺮة ﺑﻤﺸﺮوع اﻟﻐﺎﺑﺔ اﻟﺰراﻋﻲ وﻣﻨﻄﻘﺔ اﻟﻘﻮﻟﺪ ﺧﻼل ﻣﻮﺳﻤﻲ 2003/2004-2004 /2005 ﺑﻬﺪف ﺗﻘﻮﻳﻢ ﻓﻌﺎﻟﻴﺔ أرﺑﻌﺔ ﻣﺒﻴﺪات ﺟﻬﺎزﻳﺔ ،اﻣﻴﺪاآﻠﻮﺑﺮﻳﺪ ﻓﻰ هﻴﺌﺔ (Rinfidor 20%SL, Confidor 200SL وComodor 20%SL) وﺛﻴﺎﻣﻴﺜﻮآﺜﺎم ﻓﻲ هﻴﺌﺔ (Actara 25WG) ﺿﺪ ﺣﺸﺮة اﻟﻨﺨﻴﻞ اﻟﻘﺸﺮﻳﺔ اﻟﺨﻀﺮاء اﻟﺤﺎﻓﺮة (Palmapsis phoenicis Ramachandra Rao) ﺑﻤﺸﺮوع اﻟﻐﺎﺑﺔ اﻟﺰراﻋﻲ وﻣﻨﻄﻘﺔ اﻟﻘﻮﻟﺪ وذﻟﻚ ﺑﺎﺳﺘﺨﺪام ﻃﺮﻳﻘﺘﺎن ﻟﻠﻤﻌﺎﻣﻠﺔ ( ﻣﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﺔ و ﺣﻘﻦ اﻟﻤﺒﻴﺪ ﻓﻲ ﺳﺎق اﻟﻨﺨﻠﺔ ). أﺳﺘﻬﺪﻓﺖ اﻟﺘﺠﺎرب ﺗﺤﺪﻳﺪ اﻟﺠﺮﻋﺔ اﻟﻔﻌﺎﻟﺔ وﻓﺘﺮة ﺛﺒﺎت هﺬﻩ اﻟﻤﺒﻴﺪات (Persistence) وآﺬﻟﻚ اﻷﺛﺮ اﻟﻤﺘﺒﻘﻲ ﻋﻠﻲ اﻟﺜﻤﺎر واﻟﺘﺮﺑﺔ واﻟﺰراﻋﺎت اﻟﺒﻴﻨﻴﺔ.

أﺳﺘﺨﺪﻣﺖ اﻟﺠﺮﻋﺎت ﺻﻔﺮ، 20، 25 و35 ﻣﻞ\ﻟﻠﻨﺨﻠﺔ و 10 ,15 و20 ﻣﻞ /ﻟﻠﻨﺨﻠﺔ ﻣﻦ ﻣﺒﻴﺪات ( Rinfidor 20%SL و Comodor 20%SL ) ﻟﻤﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﺔ واﻟﺤﻘﻦ ﻋﻠﻲ اﻟﺘﺮﺗﻴﺐ . اﻣﺎ ﻣﺒﻴﺪ Actara 25WG ﻓﻜﺎﻧﺖ ﺟﺮﻋﺎﺗﻪ هﻲ9, 12, 15 و18 ﺟﺮام /ﻟﻠﻨﺨﻠﺔ و 6 ,8 و10 ﺟﺮام /ﻟﻠﻨﺨﻠﺔ ﻟﻄﺮﻳﻘﺘﻲ ﻣﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﺔ واﻟﺤﻘﻦ ﻋﻠﻲ اﻟﺘﺮﺗﻴﺐ اﻣﺎ ﻣﺒﻴﺪ آﻮﻧﻔﻴﺪور Confidor 200 SL اﺳﺘﺨﺪم ﺑﺎﻟﺠﺮﻋﺔ 35 ﻣﻞ /ﻟﻠﻨﺨﻠﺔ آﻤﺒﻴﺪ ﻗﻴﺎﺳﻲ ﻓﻲ ﻃﺮﻳﻘﺔ ﻣﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﻪ و ﺑﺎﻟﺠﺮﻋﺎت 10 ,15 و20 ﻣﻞ /ﻟﻠﻨﺨﻠﺔ ﻓﻲ ﻣﻌﺎﻣﻠﺔ اﻟﺤﻘﻦ . ﺗﻢ ﺗﺨﻔﻴﻒ ﺟﺮﻋﺎت اﻟﻤﺒﻴﺪات (ﻣﻌﺎﻣﻠﺔ اﻟﺘﺮﺑﺔ ) ﻓﻲ (8) ﻟﺘﺮ ﻣﺎء ووزﻋﺖ ﺑﺎﻧﺘﻈﺎم ﺣﻮل ﺟﺬع اﻟﻨﺨﻠﺔ ﺑﻌﺪ أﺟﺮاء ﻋﻤﻠﻴﺎت اﻟﺘﺤﻮﻳﺾ (ﺑﻘﻄﺮ 3م) واﻟﺘﻘﻠﻴﻢ ﺛﻢ اﻟﺮى ﺑﺎﻧﺘﻈﺎم آﻞ (10) أﻳﺎم. اﺳﺘﺨﺪم اﻟﻨﻈﺎم اﻟﻌﺸﻮاﺋﻲ آﺎﻣﻞ اﻟﻘﻄﺎﻋﺎت ﺑﻌﺪد ارﺑﻌﺔ ﻣﻜﺮرات (ﺳﺘﻪ ﻧﺨﻼت ﺗﻤﺜﻞ آﻞ ﻣﻜﺮر). ﺗﻢ ﺗﻌﺪاد آﻞ اﻻﻃﻮار اﻟﺤﺸﺮﻳﺔ ( ﺳﻢ2 /ورﻳﻘﺔ) ﻓﻲ ﺛﻤﺎﻧﻴﺔ ورﻳﻘﺎت ﻣﻦ آﻞ ﻧﺨﻠﺔ ﺑﻌﺪ آﻞ اﺳﺒﻮﻋﻴﻦ ﻣﻦ ﺑﺪاﻳﺔ اﻟﻤﻌﺎﻣﻠﺔ. آﺬﻟﻚ ﺗﻤﺖ دراﺳﺔ اﻗﺘﺼﺎدﻳﺔ ﻃﺮﻳﻘﺔ اﻟﻤﻜﺎﻓﺤﺔ .ﺗﻢ ﺗﻘﻮﻳﻢ ﻗﺎﺑﻠﻴﺔ ﺑﻌﺾ اﻻﺻﻨﺎف ﻟﻼﺻﺎﺑﺔ آﻤﺎ ﺗﻢ ﻣﺴﺢ ﻟﻼﻋﺪاء اﻟﺤﻴﻮﻳﺔ.

ABSTRACT A series of small scale field experiments were carried out in Elgaba scheme, and El Golid area during seasons (2003/2004 - 2004/2005) to evaluate the efficacy of four systemic insecticides; imidacloprid as Confidor 200SL, Rinfidor 20%SL and Comodor 20% SL and thiamethoxam as Actara 25WG, against the green pit scale insect (Palmapsis phoenicis Ramachandra Rao) Two methods of application, soil application and trunk injection were used. The insecticide thiamethoxam as Actara 25WG was tested at 9, 12, 15 and 18g /palm and 6, 8 and 10g/palm for soil application and trunk injection, respectively. While imidacloprid as Rinfidor 20% SL and Comodor 20% SL was tested at 20, 25 and 35 ml/palm and 10, 15 and 20 ml/palm for soil application and trunk injection, respectively. Confidor 200SL (imidacloprid) was used as standard (35ml/palm) for soil application and 10, 15 and 20 ml /palm for trunk injection The specific dose was diluted with eight liter of water in a container and drenched around the date palm tree (3m id) and then irrigation scheduled every 10 days. The Completely Randomized Design with six replicates (one palm = replicate) was used. The insects (all developing stages) were counted (cm2/leaflet). Eight leaflets from each palm were inspected at biweekly intervals. Dates yield and quality were determined at harvest. Residue analysis was carried out on dates, soil and intercropped plants twice (at rutab stage and harvesting). The economics of control using this method were studied .Varietal susceptibility and expected natural enemies were also investigated. Results indicated that the % mortality (adult and immature stages) were significantly higher in insecticides treatments than the untreated control by the two application methods. Results of residue analysis indicated that, no residues of both imidacloprid and thiamethoxam were detected in dates, soil and intercropped plants when treated with the high doses. The higher doses remained effective throughout the experimental period. Date palm treated with the higher doses of tested insecticides, developed normally and the dates reached maturity (ripening) and the yield was increased by more than 70% compared with the untreated control. All insecticides checked termites and many other pests, but did not affect mites. The two methods of application were found highly economical and safe for the users with minimal environmental impacts. Partial budget analysis indicated the profitability of the two packages as indicated by the marginal rate of returns of 364 % for imidacloprid. Survey of the natural enemies recorded two beetles associated with the pest. Among the four varieties tested Gondiella was the most susceptible variety while the least susceptible variety was Wad laggi.

xi 1: INTRODUCTION

Date palm (Phoenix dactylifera L.), is considered one of the most important fruit crops, and provides a primary article of food and commerce in the great desert areas of Western North Africa to India, and many other subtropical areas. The tree is drought and salt tolerant, and its tasty fruits have high nutritional value and good storage properties. Date fruits constitute the most important agricultural crop in the area and provide highly nutritious food as well as a primary source of income to the majority of the inhabitants. The date palm offers a good food source of high nutritive value (Shinwari, 1993). Furthermore, the date palm tree tolerates relatively harsh climatic and soil conditions under which no other crop may give reasonable returns. In fact, date palm which is an irreplaceable tree in irrigable desert lands, provides protection to under-crops from heat, wind and even cold weather, and plays a big role in combating desertification. Its fruits generate foreign exchange earnings. Its dried fruit bunches, fronds, leaflets fiber and trunks are utilized in many small industries as packing materials in local marketing of fruits and vegetables as well as for many other purposes. The tree and fruit by-products offer an extra income. Timber is produced from stems, while fronds are widely used for thatching, buildings, barring and basketry (household utensils). The date palm tree is cultivated in the Northern Sudan along the banks of the Nile over a distance of about 900 kilometers. The total number of trees is about 7-8 million (Osman, 2001, Baballa 2002 and Ahmed, 2005). According to FAO (2005) the, mean annual production of dates is 328.2 metric tons. This ranked Sudan as the 7th largest producer of dates among Arab countries.

However, the date palm industry is facing many serious problems, related to low yields, lack of appropriate packing and presentation as well as limited processing of date products. The estimated average yield of bearing date palm tree in the main date growing areas in Sudan is around 20 kg, which is very low compared to the average yield of more than 100 kg in other date growing areas (USA, Qassim in Saudi Arabia and Namibia,) (FAO, 2002). The low yields in most countries, including Sudan, are 1 due to soil salinity, poor fertility, insect pests and diseases, lack of maintenance and care due to increasing cost of labour and to shortage of personnel trained in improved cultural practices. As a result of the high cost of production and low prices of the produce, farmers tend to neglect or even abandon their orchards. Although the commonly known, insect pests like red weevil and diseases like bayoud have not been reported, in Sudan, the yield of the date palm is affected by many biotic factors among which insects are the most important.

In the Sudan, the green date palm pit scale insect, Palmapsis phoenicis Ramachandra Rao (Asterolecanium phoenicis Rao.) is considered the key pest. This genus, a native of central Asia (Iran), (Ezz, 1973 and Sherif, 1967) was not known in Sudan before 1989 when it was firstl reported by Ali (1989) in El Golid area, as a result of an introduction of some offshoots from Saudi Arabia in 1974. Later, the pest crossed the natural barrier of Baja desert to invade Elgaba scheme, (150 km south of Dongola, 400km-north of Khartoum) and has become a real threat to date palm cultivation in Northern Sudan. The infested area in El Golid, Elgaba and Old Dongola is about 5000 hectares, extending over 60 and 50 kilometers along the west and east banks of the river Nile respectively. The newly reported infestation in Artigasha Island, Burgag scheme and Orbi in Dongola area, Abuhamad in the River Nile State (23000 infested palm trees) and Khartoum State, provides evidence that the pest may continue to spread.

The insect attacks the leaflets, leaf rachis and fruits. It causes chlorosis, degeneration of the leaves, malformation of fruits before maturity leading to losses in production from a range of 30-50 kg to 5 kg per tree (Ali et.al. ,1992). The losses may range between 85 and 90% according to infestation rate, variety infested and management conditions (Ahmed ,2001 and 2004) . In the past, and due to lack of indigenous knowledge of the nature of this pest, control efforts were not successful; hence the level of infestation steadily increased.

Based on growing importance of this pest, its serious impact on date production, this study was initiated to investigate the possible control measures for the green date palm pit scale insect. Thus the main objectives of this study were: 1- To determine the efficacy of imidacloprid and thiamithoxam compounds in controlling the date palm green pit insect.

2- To evaluate the efficacy of these compounds against re infestation by this insect.

3- To study the effects of tested compounds on other insect pests of the date palm.

4- To check the residues of tested compounds in dates, soil, water and intercropped plants.

5- To assess the economic impact of soil application and improved cultural practices versus the traditional farmers’ practices.

6- To determine varietal susceptibility of date cultivars and assess the impact of natural enemies of the pit scale insect in the Northern State, Sudan.

2: LITERATURE REVIEW

2.1 The date palm tree. 2.1.1 Economic importance The date palm offers a good food source of high nutritive value; this tree gives many date growing countries in remote areas, the main food for a considerable number of people and provides working conditions to considerable numbers of laborers in the rural areas. Furthermore, the date palm tree tolerates relatively harsh climatic and soil conditions under which no other crop may give reasonable returns. In fact, date palm which is an irreplaceable tree in irrigable desert lands, like many areas in the northern Sudan, provides protection to under-crops from heat, wind and even cold weather, and plays a big role in checking desertification and giving life to desert areas (FAO, 1982 and 2002.). Its fruits generate good income and foreign exchange earnings. Its dried fruit bunches, fronds, leaflets fiber and trunks are utilized in many small industries which provide packing materials for local marketing of fruits and vegetables as well as for many other uses (FAO, 2002). The tree and fruit by-products offer an extra income.

However, the date palm industry is facing many serious problems, in addition to low yields, such as the lack of appropriate packing and presentation and the limited processing into sound industrial date products. The estimated average yield bearing date palm tree in the main date growing areas is around 20 kg, which is very low compared to the average yield of more than 100 kg in some date growing areas (USA, Qassim in Saudi Arabia and Namibia). The low yields in Sudan, are due to soil salinity, poor fertility, insect infestations, diseases, lack of maintenance and care due to increasing cost of labour and shortage of trained personnel in improved cultural practices (Obied, 1987; Osman, 1992 and Ahmed, 2003). As a result of the high cost of production and low prices of the produce, farmers tend to neglect or even abandon their orchards.

2.1.2 Origin of date palm The exact origin of the date palm (Phoenix dactylifera L.) is considered to be lost in Antiquity. However, it is certain that the date palm was cultivated as early as 4000 B.C. since it was used for the construction of the temple of the moon god near Ur in Southern Iraq - Mesopotamia (Popenoe, 1913 and 1973).

More proof of the great antiquity of the date palm is in Egypt's Nile Valley where it was used as the symbol for the year in Egyptian hieroglyphics and its frond as a symbol for the month (Dowson, 1982). However, the culture of date palm did not become important in Egypt until somewhat later than that of Iraq, about 3000 - 2000 B.C (FAO, 2002).

The above is confirmed by history and corroporated by the archaeological research into old historical remains of the Sumerians, Akadians and Babylonians. Houses of these very old people were roofed with palm tree trunks and fronds. The uses of date for medicinal purposes, in addition to its food value, were also documented (Mark and Shepherd, 2001).

In conclusion, date palm is probably the oldest cultivated tree in the world. It could be safely assumed that the reason for mentioning dates and date palms in the Jewish, Christian, and Islamic religions was due mainly to the influence of the Prophet Ibrahim, who was born and raised in the old city of Ur where date palms were grown. Ibrahim's love of the date and date palm left a lasting influence on these religions (Zaid and Wet, 2002).

The Holy Koran mentioned dates and date palm in 17 Suras (chapters), out of the 114 Suras and 20 verses out of 6,263 verses. Prophet Mohammed (peace be upon him) is reported to have said that the best property is date palm that dates cure many disorders and he urged Muslims to eat the date and tend to the date palm. Where the date palm

5 originated is not known (Zaid and Wet, 2002). Although widely cultivated, no truly wild plant has ever been found. Its progenitor is believed to be Phoenix reclinata Jacq from tropical Africa, or Phoenix sylvestris (L). Roxb. from India, or a hybrid between these two ( Zaid and Arias ,1999).Both these species have palatable, although inferior fruits.

The spreading of the date palm and its cultivation occurred during the past centuries following two distinct directions: 1- One starting from Mesopotamia to Iran, to reach the Valley of the Indus and Pakistan; 2-The date propagation in Africa was realized using the same itineraries as those of the Neolithic civilization but with some delays. It is illustrated by the presence of Sudan date plantations around the Neolithic sites. According to Dowson (1982), date palm covers 3 % of the world's cultivated land surface.

In 1912, the date palm was introduced into the western part of North America (Colorado Desert, Atacama Desert and other regions) (Wright, 2006).

2.1.3 Geographical distribution of date palm Date palm is found in both the Old World (Near East and North Africa) and the New World (American continent) where dates are grown commercially in large quantities. The date belt stretches from the Indus Valley in the east to the Atlantic Ocean in the west. In order to have a clear picture on the geographical distribution of date palm, it is worth looking at it from the following aspects: (i) Distribution according to latitude, (ii) Distribution according to altitude, and (iii) Number of date palms in the world. (Zaid and Wet, 2002). (i) Distribution according to latitude The extreme limits of date palm distribution are between 10°N (Somalia) and 39°N (Elche/Spain or Turkmenistan). Favorable areas are located between 24° and 34°N (Morocco, Algeria, Tunisia, Libya, Egypt, Iraq, Iran) (Zaid and Wet, 2002)..In 6

USA, date palm is found between 33° and 35°N. Because of climatic factors, the date palm tree can grow, but produce no proper fruit outside the above defined geographical limits. (ii) Distribution according to altitude Altitude is very important since it imposes the availability of water and the temperature limits which largely determine the distribution of date palm in the world. In fact, date palm grows and flourishes from 392 m below to 1,500 m above sea level. (Zaid and Wet, 2002). (iii) Number of date palms in the world The world total number of date palms trees is about 100 million, distributed in 30 countries, and producing about 6.5 million tons of fruit per year (Hashempoor and Beigi, 2007). If we look at the distribution region by region we find that Asia is in the first position with 60 million date palms trees (Saudi Arabia, Bahrain, UAE, Iran, Iraq, Kuwait, Oman, Pakistan, Turkmenistan, Yemen); while Africa is in the second position with 32.5 million date palms (Algeria, Egypt, Libya, Mali, Morocco, Mauritania, Niger, Somalia, Sudan, Chad, Tunisia).(FAO, 2002).

Mexico and the USA have 600,000 palms followed, by Europe (Spain) with 32,000 and Australia with 30,000. Iraq is leading with 22 million palms, followed by Iran 21 million and Saudi Arabia with 12 million, Algeria 9 million, Egypt and Libya 7 million each, Pakistan and Morocco 4 million each. The remaining date growing countries have less than 1 million palms each. According to (FAO, 2005) the world total production of dates is 16,696.59 (1000 tones) and the top ten producers countries are: Iraq , Saudi Arabia , Egypt ,Iran , United Arab Emirates , Algeria ,Pakistan , Sudan , Libya and China , they produced : (7,170 ) , (4, 971) , (1,170) , (880) , (760) , (516.29), (496.58) , (328.20) , ( 150) and 130 ( 1000 tones), respectively .

2.1.4 Botanical and Morphological Description Date palm belong to the Angiosperms-Monocotyledons, Palmaceae is a family of about 200 genera and 1,500 species (Dowson, 1982). Phoenix (Coryphoideae Phoeniceae) is one of the genera which contain a dozen species, all native to the tropical or subtropical regions of Africa or Southern Asia, including Phoenix dactylifera L. ( Baballa 2002 and FAO, 2002). Besides date palm, five other species bear edible fruit (P. atlantica chev. P. reclinata Jacq. , P. farinifera Roxb, P. humilis Royle, and P. acaulis Roxb.). Most of the 12 Phoenix species are well known as ornamentals, the most highly valued is P. canariensis Chabeaud, commonly called the Canary Island Palm. P. sylvestris Roxb. is widely used in India as a source of sugar. P. dactylifera L. is distinguished from the above two species by several characteristics which could be summarized as follows:

2.1.4.1 Root system Being a monocotyledon, date palm has no tap root. Its root system is fasciculate and roots are fibrous, similar to a maize plant. Secondary roots appear on the primary root which develop directly from the seed. These secondary roots produce lateral roots (tertiary roots and so on) of the same type with approximately the same diameter throughout their length.

All date palm roots present pneumatics, which are respiratory organs. Roots are found as far as 25 m from the palm and deeper than 6 m, but 85 percent of the roots are distributed in the zone of 2 m deep and 2 m on both lateral sides in a deep loamy soil (Oihabi, 1991). It is worth mentioning that date roots can withstand wet soil for many months, but if such conditions spread over longer periods, they become harmful to the health of the roots and to fruit production. Plate 1, diagrammatically shows a date palm's construction with its root system. It is clear that the date palm root system is divided into four zones (Oihabi, 1991):

- Zone I, called respiratory zone: It is localized at the palm base's surrounding area with no more than 25 cm depth and a lateral distribution of a maximum of 0.5 m away from the stripe. Found in this zone are mainly roots of primary and secondary nature. Most of these roots have a negative geotropism and play a respiratory role. - Zone II, called nutritional zone: It is a large zone and contains the highest proportion of primary and secondary roots. It could contain 1000 roots per m² and more than 1.60 g of roots/100 g soil (Oihabi, 1991). They develop between 0.90 and 1.50 m depth and could laterally be found outside of the projection of the tree's canopy. In the case of Deglet Nour variety, lateral roots were found up to 10.5 m from the trunk (Bliss, 1944). Recently planted offshoots develop their roots at zone II then at zone III. At one year old, they could reach 1 m, while 3 m depth is easily reached at the second year. - Zone III, called absorbing zone: The importance of this zone is dependent on the type of culture and on the depth of underground water. It is usually found at a depth of 1.5 to 1.8 m. mostly primary roots with a decreasing density from top to bottom here. The density of this zone is lower than in zone II - only about 200 roots are found per m². - Zone IV: The largest portion of this zone is dependent on underground water. At a shallower depth, it becomes difficult to distinguish between Zone III and Zone IV as both types of roots are found here. When the underground water is deep, roots of this zone could reach a greater depth.

In conclusion, the root type and distribution illustrate the role of the date palm. The lack of roots in the top soil allows other cultures such as wheat, lucerne and vegetables to be inter-cropped. While, the high concentration and deep presence of primary roots allows the date palm to benefit from underground moisture.

Date palm root development and distribution depends on soil characteristics, type of culture, depth of the underground water and variety

Plate 1. Diagrammatic construction of a date palm with its root system

(Source: Oihabi, 1991)

2.1.4.2 Trunk

The date palm trunk, also called stem or stripe is vertical, cylindrical and columnar of the same girth all the way up. The girth does not increase once the canopy of fronds has fully developed. It is brown in colour, lignified and without any ramification (Plate 1). Its average circumference is about 1 to 1.10 m.

The trunk is composed of tough, fibrous vascular bundles cemented together in a matrix of cellular tissue which is much lignified near the outer part of the trunk. Being a monocotyledon, date palm does not have a cambium layer.The trunk is covered for several years with the bases of the old dry fronds, making it rough, but with age these bases wattle and the trunk becomes smoother with visible cicatrices of these bases. Vertical growth of date palm is ensured by its terminal bud, called phyllophor, and its height could reach 20 meters.

Horizontal or lateral growth is ensured by an extra vascicular cambium which soon disappears, and which results in a constant and uniform trunk width during the palm's entire life. However, the terminal bud could experience an abnormal growth caused by a nutritional deficiency, which leads to shrinkage of the trunk. This stage is mainly caused by drought conditions.

Sometimes date palms show a branching phenomenon, which was studied by Zaid (1987) and found to be attributed to several causes.

2.1.4.3 Leaves Depending on variety, age of a palm tree and environmental conditions, leaves of a date palm are 3 to 6 m long (4 m average) and have a normal life of 3 to 7 years. The greatest width of the frond midrib attains 0.5 m, but elsewhere it is only half this size and rapidly narrows from the base upwards. The frond midrib or petiole is relatively triangular in cross section with two lateral angles and one dorsal. It is bare 11 of spines for a short distance but full of spines on both sides thereafter. Intermediate zones have spine-like leaflets, also called leaflet-like spines.

At the tip of the leaf, there may be a single terminal leaflet or two leaflets forming a V. Leaf structure which is variety and environment dependent, but usually the whole length of a frond has the following proportions: - The distance from the fiber at the base of the frond to the base of the spine- leaflets is about 28 % of the whole frond; - The spine-leaflets occupy about 4 %; - The leaflets occupy about 62 %; and - The terminal leaflets occupy about 6 %. All these characteristics coupled with others, are used as a taxonomical index to differentiate between varieties. Unlike other fruit trees, dead or old leaves are not shed and do not drop on their own, but are removed by pruning.

An adult date palm has approximately 100 to 125 green leaves with an annual formation of 10 to 26 new leaves. The functional value of the leaf to the palm declines with age and no two leaves are the same age. Furthermore, leaves which are four years old are only about 65 percent as efficient in photosynthesis per unit area, compared to leaves of one year old (Nixon and Wedding, 1956). Leaves are grouped in 13 nearly vertical columns, spiraling slightly to the left on some palms and to the right on others. The grower must only count the number of leaves in one of these columns and multiply it by 13. According to Nixon and Carpenter (1978) and in order to allow for uneven pruning at the base, counts could be made on opposite sides and divided by two. This technique will allow the grower to calculate the total number of leaves on the palm. A ratio of 8 leaves per fruit bunch will indicate how many bunches to leave on that palm.

2.1.4.4 Fiber, spines and leaflets As well described by Dowson (1982), the base of the frond is a sheath encircling the palm. This sheath consists of white connective tissue ramified by vascular bundles. As the frond grows upwards, the connective tissue largely disappears leaving the dried, and now brown, vascular bundles as a band of tough, rough fiber attached to the lateral edges of the lower part of the midribs of the fronds and unsheathing the trunk. Varieties differ in the height to which the fiber grows up the central column of unopened fronds, and in the texture of the fiber and also somewhat in colour. Spines, also called thorns, vary from a few cm to 24 cm in length and from a few mm to 1 cm in thickness. They are differentially arranged on the two outer edges of the fronds while their number varies from 10 to about 60. Spines can be single, in groups of two, or in groups of three.

2.1.4.5 Reproductive organs Date palm is a dioecious species with male and female flowers being produced in clusters on separate palms.These flowering clusters are produced with axils of leaves of the previous year's growth.The unisexual flowers are pistillate (female) and staminate (male) in character; they are borne in a big cluster (inflorescence) called spadix or spike, which consists of a central stem called rachis and several strands or spike lets (usually 50 - 150 lateral branches).

2.1.4.6 Inflorescences/Flowers The inflorescence, also called flower cluster, in its early stages is enclosed in a hard covering/envelope known as spathe which splits open as the flowers mature exposing the entire inflorescence for pollination purposes. The spathe protects the delicate flowers from being shriveled up by the intense heat until these are mature and ready to perform their function. The spathe at the beginning is greenish, becoming brown near splitting - splitting is longitudinal. The male spathes are shorter and wider than the female ones. Each spike let carries a large number of tiny flowers as many as 8,000 to 10,000 in female and more in male inflorescence (FAO, 2002). 13

2.1.4.7 Fruit Depending on the variety, environmental conditions and the technical care given (fertilization, pollination, thinning,), fruit characteristics vary tremendously. The date fruit is a single, oblong, terette, one-seeded berry, with a terminal stigma, a fleshy pericarp and a membranous endocarp (between the seed and the flesh). The weight ranged from 2 to 60 grams and length and width ranged from 1.8 to 11.0 and .8 to 3.2 (cm), respectively .The colour has a large variation from yellow to black and the consistency is soft to dry.

2.1.4.8 Seed As with the fruit, seed characteristics vary according to variety, environmental and growing conditions. A seed's weight could range from less than 0.5 g to about 4 g, with a length from 12 to 36 mm and width of 6 to 13 mm. The seed is usually oblong, ventrally grooved, with a small embryo, and with a hard endosperm made of a cellulose deposit on the inside of the cell walls.

2.1.4.9 Variety description Date varieties have been developed by thousands of years of selection of seedlings and only those possessing desirable characteristics have been propagated. Date palm counts for more than 3,000 varieties all around the world. There are about 400 in Iran, 370 in Iraq, 250 in Tunisia, 244 in Morocco, as well as many additional varieties in the other major date growing countries (FAO, 2002).

Several date specialists attempted to list and to botanically describe the varieties grown in their respective countries (Brown, 1924 and 1938; Mason, 1925; Dowson, 1923; Kearney, 1906; Nixon, 1950, Baballa 2002 and Zaid and Wet, 2002).

In Sudan and through the years and as a result of practicing the date palm production especially in the Northern states , good quality dates are developed and being handled

14 from generation to another (Osman ,2001and Baballa,2002). Out of the total amounts of dates produced in the Northern region about 75% are dry dates, the other 25% soft or semi dry. The hot and dry spells during the summer period encourage dry dates production (May to September). Thus dry dates produced are characterized by their high stability and can tolerate varied techniques of handling and packing with minimum losses or damages. The varieties grown as dry or soft dates have local names like Barakawi, Gondeilla, Bittamud, Mishrig/Wadlagi, Mishrig /Wadkhateeb, Medina, Kulma, Aelrahim, Tunisi-Jaw, Digltour, Gorair.

It is uncertain whether the Sudanese date cultivars originated endogenously or were introduced; however, it is most likely that Barakawi, Gondeilla, and Tamoda originated within the geographical zone covering Southern Egypt and Northern Sudan. Other cultivars such as Mishrig Wad Khateeb, Mishrig Wad Lagai and Gorair are of indigenous origin, where as Medina as the name indicates might have been introduced from Saudi Arabia, and Tunisi from Tunisia.

Date palm propagation is chiefly achieved through seeds or offshoots and air layering (offshoots rooting), and tissue culture. The later is still at its infancy stage, since it needs special trained caliber. Few farmers tend to raise seedlings of date palms from seeds because this practice results in new and heterogeneous varieties known collectively as, Jaw. Very few of these Jaw varieties prove themselves as bearers of good quality dates. Generally this method is very limited and very unpopular. In this case, seeds are planted in a nursery or in the field, with several seeds per hole, but more commonly they are allowed to develop to the flowering stage. At this time any male trees may be removed. Regarding offshoots and air layering, it is perfectly recognized that most date palm cultivars tend to bear some offshoots at the base of the trunks above soil level. Offshoots are being cut at suitable size from the parent plant and directly planted in the soil, but owing to the poor survival rate, they are encouraged to root while still attached to the parent palm by surrounding the bases of

15 offshoots with damp soil in a bottomless container, after root formation, the offshoots are excised from the parent palm and planted out. Planting of already rooted offshoots greatly increases the survival of the young date palm replants. Both seedlings and offshoots are used to fill spacing in existing plantations or to establish new plantations. Offshoots method produces palms of exactly the same genetic constitution as their parents, and it is the preferred method of propagating quality cash crop varieties. Formerly offshoots cut from the parent palm or seedlings from seeds are usually planted 3-4 meters apart, with one male for every 50 female trees.

2.1.5 Cultural practices (Irrigation, Fertilization, Pollination, Bunch Management and Fruit thinning) In Northern Sudan, the young palms are irrigated initially at fortnightly intrevals, then monthly for 1-2 years until establishment. On the banks of the Nile irrigation is seldom continued for more than two years, but further inland, several irrigations per year are provided for the first ten years.On the upper terraces, monthly irrigation may be required throughout the life of the palm. A study conducted by Alihouri (2007) indicated that, the effect of irrigation intervals on fruit set, fruit drop, fruit length, pit weight and length and palm yield were significant in Berhee cultivar.

Farmers intercrop young palm with bean, alfalfa, vegetables, herbs, spices, condiments and other crops ensuring that the palms receive some irrigation, fertilization and additional nitrogen from leguminous plants, intercropping ceases after 3-10 years and the palms receive little further attention. Irrigation is minimal, no fertilizer is applied and offshoots are allowed to grow unchecked, resulting in multi-stemmed palms.

The date palms are dioecious, bearing male and female flowers on different palms. The growers climb the trees during the flowering season to carry pollen by hand from male to the female. No mechanical method is applied such as hand operated machine from ground level. Artificial pollination is effected by collecting male spathes before

16 they burst or shortly after wards. One to four male strands are made into small bundles and each inserted into female inflorescence. If dry pollen is to be used it is normally dusted on cotton balls which are then placed in the center of the female cluster in the same manner. Pollens are selected from males blooming at about the same time with the females to provide fresh pollen in order to get successful fruit setting. The pollination is usually made early in the morning as soon as the first break in the spathe is observed. Storage of pollen or the practice of keeping pollen from one year to another is not practiced in the Sudan. On selecting a male palm the only character of significance is the number of inflorescence produced by a male plant (Zaid and Arias, 1999).

To obtain good quality fruits, care has to be taken for the bunches during all their developing stage, to protect them against hazards such as extreme, low or high temperatures, rain, insects, or birds. But in Sudan very little attention is given to bunch management. This usually results in sizable losses and lowering of fruit quality. This practice of removing some of the fruits is done for the purpose of improving the quality of the rest and the productivity of the tree in general. In most countries where commercial date culture is well developed some kind of fruit thinning is normally practiced, but in Sudan, thinning is not practised. Preliminary findings at Hudeiba research station in the River Nile State showed that thinning is necessary in many cultivars to avoid alternate bearing, Unthinned bunches of Zaglul and Madina some times shrivel and dry out. Generally speaking, it is reasonable to say that palms are of major socioeconomic and social importance in the Northern State, but date palm is still grown in Sudan at a congenital method without attention to irrigation, fertilization, or other cultivation practices. It becomes clear that date palm production and plantations considerably deteriorated in the last years. Fluctuation in climatic and environmental conditions had its role in the spread of insect pests and plant diseases. Consequently, these factors contributed to poor yield and low productivity of palms in the Northern States of Sudan (Nixon, 1967 and Osman, 1992).

2. 2 Scale insects as major insect pests of date palm The date palm and its fruits are subject to attacks by several pests. Damage caused by these pests is considerable and leads to heavy economic losses.Scale insects can be serious pests on all types of woody plants and shrubs. Scales are so unusual looking that many people do not at first recognize them as insects. Adult female scales and many immature forms do not move, are hidden under a disk like waxy covering, and lack a seperate head or other recognizable body parts. Scales have long piercing mouthparts with which they suck juices out of plants. They may occur on twigs, leaves, branches, or fruit. Severe infestations can cause overall decline and even death of plants (Miller et. al, 2005). Most scales have many natural enemies that often effectively control them (El Fahal, 1993). Armored scales and soft scales are the most common types of scales on woody plants.

Woody plants heavily infested with armored scales often look as if under water stress. Leaves may turn yellow and drop, twigs and limbs on trees may die, and bark may crack and produce gum. Many armored scales attack leaves or fruit as well leaving blemishes and halos on fruit; the fruit damage is often just aesthetic.Some armored scales can kill plants. Soft scales also reduce tree vigor but seldom kill trees

The major concern with these scales is their production of abundant quantities of honeydew, which gets on leaves and fruit, encouraging the growth of black sooty mold. Honeydew also attracts ants, which protect soft scales from natural enemies; the presence of ants on a tree or shrub is a good indication of an infestation by a honeydew-producing insect. Soft scales infest leaves and twigs but do not attack fruit directly.

Scales are often well controlled by natural enemies, especially when predator and parasite activities are not disrupted by ants or applications of broad-spectrum insecticides such as carbaryl, Malathion, or pyrethyroid applied to control other pests.

If scale populations, especially armored scale species, become abundant, action should be taken. In the case of soft scales, controlling ants may be sufficient to bring about gradual control of scales as natural enemies become more abundant. If not, well-timed sprays of oil (specially refined oils, often called narrow-range, supreme, or superior type oils), applied either during winter or when crawlers are active in spring (or, in the case of black scale, in summer) should provide good control (Gharib, 1974).

Monitor scales by inspecting plants for crawlers, mature females, or ants. Dead scales from previous generations can remain on plants and it is important to distinguish live scales from dead ones. On landscape plants, action thresholds have not been established for scales. Growers should develop thresholds for their local situation. They should also monitor and record scale densities and use the density that caused damage (dieback or unacceptable honeydew) as preliminary control action threshold. This threshold must be refired over time as experience is gained. Deciduous plants should be examined when leaves are gone in winter. Armored scales over winter primarily as first-instars nymphs and adult females, whereas soft scales commonly over winter as second-instars nymphs. On deciduous trees and bushes, twigs and branches heavily infested with scales may retain their leaves during winter and be easy to spot. Citrus, avocado, and other plants that do not enter winter dormancy can be monitored by examining leaves, twigs, limbs, and fruit for evidence of a scale infestation. During the growing season, trunks should be inspected for ants, which may indicate a soft scale infestation. If the descending ants have swollen, almost translucent abdomens, they are probably feeding on honeydew produced by scales or other insects that suck plant juices (Zaid and Arias, 1999).

Scales are often controlled by natural enemies, including many species of crawler, white cap nipple stage, second-instars female, second-instars mal, virgin female adult , third- and fourth-instars male (underside) gravid female (underside) male adult, first instar crawlers, mature females ,second instars on twig, females before egg laying,

19 beneath female scale, settled first instars, small, dark, lady beetles. Hyperaspis species are tiny, shiny, black lady beetles with several red, orange, or yellow spots on the back. Rhyzobius lophanthae is a lady beetle that has a reddish head and underside, and a grayish back densely covered with tiny hairs. The twice stabbed lady beetle, Chilocorus orbus, is shiny black with two red spots on its back, and reddish underneath. The larvae of certain predaceous lady beetles can be found under the female soft scales feeding on scale eggs and crawlers. Many parasitic wasps are important natural enemies of scales, including species of Aphytis, Coccophagus, Encarsia, and Metaphycus. Parasite activity can be estimated by checking scale covers for round exit holes made by emerging adult parasites. Covers of armored scales shall be removed to examine beneath them for immature parasites. Flowering plants should be grown near scale-infested trees and shrubs to help augment natural enemies. Adult parasitic wasps live longer, lay more eggs, and kill more scales when they have nectar or honeydew to feed on. Dust control is crucial to the success of biological control. Plant surfaces must be washed midseason, or when the foliage is dusty, to encourage biological controls. Natural enemies are commercially available for release against black scale and California red scale. However, conserving resident natural enemies is a more efficient and long lasting strategy than buying and releasing them, particularly in garden situations. Depending on the scale species and the extent to which biological control has been disrupted, it may take several months of conservation efforts before scale populations are reduced by biological control. If current levels of scales are intolerable, use a short residual insecticide such as oil or soap to reduce scale populations while conserving natural enemies (Mohamed, 1991).

If large numbers of ants are climbing up trunks to tend scales they should be controlled. Ant’s access to plant canopies should be denied by pruning branches that provide a bridge between buildings or the ground and by applying a sticky material (such as Tangle foot or Stikem) to trunks. If trees are young, thin-barked, or recently pruned, the trunk should be wrapped first with a strip of fabric tree wrap, duct tape, or

20 another material to prevent injuring the tree. Alternatively, or as a supplement, place enclosed pesticide baits such as ant stakes near nests or on ant trails beneath plants.

Dormant season applications of specially refined oils, often called narrow-range, supreme, or superior type oils, are effective against most scale pests of deciduous trees and landscape plants, especially San Jose scale, walnut scale, and the lecanium scales, but not against oyster shell or olive scales because susceptible stages of these pests are not present during winter. Avoid oils called dormant oil or dormant oil emulsions, which are more likely to injure plants. Treatments can be made any time during dormancy or, for sycamore scale and oak pit scales, during the delayed dormant period, which is the time after the buds swell but before they open. Be sure that the plants are not water stressed to avoid injury (Sidding 1975). A good time to apply oils is right after a period of rain or foggy weather. An application of oil or soap alone is usually adequate. One study (of sycamore scale) found that organophosphates (e.g., Malathion) combined with oil were no more effective than properly timed, thorough application of oil or soap alone. Avoid using the organophosphates chlorpyrifos (Dursban) and diazinon in landscapes and gardens because of problems from their runoff in urban surface water and contamination of municipal wastewater.

In addition to narrow-range oil, insecticidal soap and carbamate insecticides are registered as foliar sprays for scale control. Foliar sprays of the more persistent, broad- spectrum insecticides (carbamates) cause greater disruption of biological control than oil or soap treatments because persistent residues continue to kill natural enemies migrating in after the application. Soil applications of imidacloprid can provide long- term control of soft scales and armored scales (Ahmed, 2001). In addition, the insect growth regulators diflubenzuron (Adept and Dimilin) and kinoprene (Enstar II) are available and are applied as sprays to infested plants. These materials are relatively slow acting but eventually highly effective (FAO, 2002).

2.2.1 The date palm green pit scale insect (Palmaspis pheonicis Ramachandra Rao) The green scale of date palm was originally described in the genus Asterolecanium (Asterolecaniidae: pit scale insects) but was designated the type- species of the genus {{ Palmaspis } e} by Bodenheimer (1944). P. phoenicis can be a serious pest of date palms, causing yellowing and dieback of the leaf pinnate and scarring and reduction in value of the fruits.

2.2.1.1 Signs and symptoms of damage The insect attacks the leaflets, leaf rachis and fruits thus preventing respiration and photosynthesis (Plate 2) .It feeds on the leaflets and fruits of the date palms, covering the date clusters and shoots causing chlorosis, degeneration of the leaves, malformation of fruits before maturity leading to losses in production ranging from 30-50 kg to 5 kg per tree (Ali and El-Nasr, 1992). The losses may range between 85 and 90% according to the infestation rate, variety infested and management conditions (Ahmed, 2001 and 2004).

P. phoenicis like all pit scales does not produce honeydew. A significant increase in the dry weight/fresh weight ratio was observed in the infested trees. Total and reducing sugars were significantly higher in the infested leaflets than the healthy ones. Phenolic compounds increased significantly in the tree infested by green scale insects. Elemental contents of total N, Ca, K, Cu, Mn and Cd were different in diseased and healthy leaflets, but P, Mg, Zn, Fe, Se and B contents were unchanged. (Al-Whaibi, 1997)

2.2.1.2 Classification

The classification of the date palm pit scale insect was in a state of confusion prior to the revision of the genus Asterolecanium by Green (1922) as Asterolecanium phoenicis; however, as Mani (1982) reported, Russell (1941) identified the species

22 belonging to the genus Asterolecanium (family Asterolecaniidae) which is characterized with paired wax glands arranged in rows.

The Palmapsis phoneicis (A phoneicis Rao.), was not reported in the list prepared by Buxton (1920) on the scale insects of date palms in Iraq. However, Green (1922) received a group of coccidae collected by entomologists from Iraq, which included the P. phoenicis and it was reported as a new pest species on date palms.The species was also reported by Bodenheimer (1944) to belong to the genus Palmaspis but he clearly stated the closeness of Palmaspis to Asterolecanium group of Russell (1941).

Morrison and Morrison (1966) and Bendov and Harpaz (1985) agreed with the findings of Russell (1941). However, Gharib (1974) reported both Palmaspis phoenicis Rao, and Asterolecanium phoenicis Rao, as synonyms under the family Asterolecaniidae.

Gassouma (2003) reported that, the green scale of date palm was originally described in the genus Asterolecanium (Asterolecaniidae: pit scale insects) but was designated the type-species of the genus {{Palmaspis} e} by Bodenheimer (1944).

Cholorosis &Degeneration on leaflets Highly infested offshoot

Highly infested trees Chlorosis & malformation on Fruits

Mature adult females Adult females (Gassouma,2003)

Plate 2. Signs and symptoms of infestation on leaves and fruits and the mature adult females of the date palm green pit scale insect. 24

2.2.1.3 Morphology Armored scales which belong to the family Diaspididae, are spherical in shape and are less than 1/8 inch in diameter and have a plate like cover.They are called armored scales because the scale cover is quite dense and provides a degree of protection from pesticides and parasites. The armored scales hatch from eggs, settle down, lose their legs, and form a hard cover that is usually separate from the scale’s body. Armored scales do not excrete honeydew. Examples of armored scales include the green date palm pit scale, California red scale, greedy scale, oyster shell scale, and San Jose scale. Female of soft scales, family Coccidae may be smooth or cottony with a diameter of 1⁄4inch or less. They are usually larger and more rounded and convex than armored scales. The surface is the actual body wall of the insect and cannot be removed. Most immature soft scales retain their barely visible legs and antennae after settling and are able to move, although slowly. Soft scales produce large quantities of honeydew, which is a modified plant sap that drips from their bodies. Examples of soft scales are black scale, brown soft scale, and European fruit lecanium.

The date palm pit scale insect ,Asterolecanium phoenicis Rao (Asterolecaniidae) was described by Rao (1921) Rao and Dutt ( 1922),Green (1922), Russel( 1941), Kehat and Amitai( 1967), Ali( 1989) and others .The first instar nymph is ellipsoid ,flatten,0.4-0.6 mm long , 0.16-0.27 mm broad ,bright yellow to greenish, the dorsal surface carries a thin transparent wax plate with long and thin whitish filaments on each body ring .The margin with 28 pairs of elongate-shape filaments and the posteror part with two long filaments. The head is furnished with a pair of reddish brown ocelli and a pair of antennae. The abdomen carries three pairs of well developed legs (Kehat and Amitai, 1967).

Microscopically, the margin has two 10u setae at anterior and 28 (8-shaped) marginal pores in a single row. A row of 6-9 pairs of 8-shaped pores about half the size of the marginal ones on the dorsal surface and two very small disk-shaped pores close to

25 second and third minute 8-shaped pores in the median area are found. The antennae on the ventral surface are 6-jointed. The basal joint with one seta, the first with two, the fourth and the fifth each with one while the sixth with three long, two stout and two fairly stout setae. A quinquelocular pore was found lateral to each spiracle on the ventral surface. The legs carry a number of setae; femur with one and tarsus with five setae.

The second instar nymph was described microscopically by Kehat and Amitai (1967) as elongate, ellipsoid, flattened, 0.55 – 0.9 mm long, 0.29 – 0.44 mm broad, greenish yellow to dark yellow. Its dorsal surface is covered with a wide transparent wax and carries long thin filaments on each body ring. On the margin, 155 – 156 pairs of whitish filaments and on the sub-margin, 28 pairs of elongate S-shaped filaments. The posterior margin with two long filaments. Microscopically, the margin with 155 – 156 8-shaped pores, 10u long. The dorsal surface with 18 – 26 small 8-shaped pores; with tubular ducts in scattered groups. The ventral surface carries one-segmented antenna with two blunt and two minute setae.There is a pair of short setae anterior to the anal opening and 30 – 32 disk-shaped pores in the sub-marginal area.

The scale of the adult female is pale yellowish green (Plate 2). The body of the insect shows a reddish brown median patch. The scale is about 1.25 – 1.5 mm long and 0.75 mm wide, convex in shape and narrow posterior with long marginal fringe except on the fifth posterior part (Green, 1922). The scale is elongate and wide at the anterior third, tapering towards both ends. It is wider and rounded at posterior and convex ventrally with whitish marginal filaments and semi-circular silt for larval exit (Russell, 1941).

The adult female insect is slipper-shaped, narrow and rounded posterior (plate 2). Antennae rudimentary and with two small, relatively stout setae. Mouthparts rather large and conspicuous. The size of the adult female scale was described by Green (1922) and Russell (1941) as 1 to 1.5 mm long and 0.75 mm wide or 1.4 to 1.75 mm 26 long and 0.65 to 0.85 mm wide, respectively. Kehat and Amitai (1967) described the adult female microscopically and showed that the dorsal surface is convex with constrictions near the posterior end. It is pale yellowish green posteriorly and reddish brown to dark violet interiorly. The margin carries 156-166 filaments, resembling those of the second instar nymph, while the sub-margin carries rows of filaments resembling those of the first instar and second instar nymph.

The microscopic description of the adult female by Kehat and Amitai (1967) showed the margin with 155-156 8-shaped pores, about 10u wide in a single row. On the dorsal surface there are many 8-shaped pores, about half the size of the marginal pores. The antennae on the ventral surface are segmented and very short with two blunt and two minute setae. The female body is furnished with a disk-shaped pore on each side of the mouthparts while two parallel rows of 4, disk-shaped pores are found medianly between the mouthparts and the anal opening. Twenty four short setae are found around the genital opening, 25 – 35 quiquelocular pores extending from spiracles to body margin, a row of 10 minute setae in the sub marginal area and 50 disk-shaped pores in an irregular row, terminating parallel to the marginal 8-shaped pores. The apex of the abdomen with two 60u long setae, and two minute setae. The exuvia can be seen beside the posterior portion of the body. The young female resembles the second instar nymph in shape and can only be distinguished by size and the space between the posterior wax filaments.

2.2.1.4 Ecology, Biology and Population Density The green date palm pit scale insect produces three generations annually in Iran; two short generations in spring and summer and one long generation in autumn and winter (Gharib, 1974). In Palestine, it produces two short-lived summer generation and a protracted autumn-winter generation (Kehat and Amitai, 1967 and Avidov and Harpaz, 1969) while in Sudan it produces three generations one long winter and two short summer generations(Ali ,1989 ). In Iran, the insect over-winters as immature

27 female and pairing takes place in May (Gharib, 1974). In Palestine the development is slow during the winter months, thus the scale population remains in the second instar (Kehat and Amitai, 1967).

The developmental cycle of the female lasts 85 – 95 days in spring and summer and 150 – 180 days in autumn and winter. The males which constitute about 25% of the total population in the palms take only 50 – 60 days to develop and male flight were

observed in May – October period (Gharib, 1974). The phonological study carried out by Kehat and Amitai (1967) in betshean area in Palestine revealed that all the stages of the scale insect, except the male, occur in the area throughout the year. In this area, the autumn-winter generation starts in November with the appearance of great number of first instar nymphs, and continues for 7 to 8 months through the winter to the beginning of summer. In autumn, the population of the first instar nymphs reaches its peak early and transformed to second instar nymphs and the scale population remains in this stage in winter. With the rise of temperature in early spring, these nymphs

change to adults (Kehat and Amitai, 1967).

At the beginning of summer, the numbers of females in the population increases following the transformation of second instar nymphs into young females. These females begin, in a short time, to give rise to the second generation. The nymphs of this generation attack the fruits soon after hatching. The beginning of the third and last generation is marked by the appearance of great numbers of first instar nymphs at the beginning of September and finishes its term by the beginning of November. The nymphs of this generation attack the late fruits as they begin to ripen. The adults of the third generation that appear in October give rise to winter generation that appear in October which give rise to winter nymphs (Kehat and Amitai, 1967).

In damp groves with a relative humidity of over 50-60%, Parlatoria blanchardii (Targ.) was found together with Asterolecanium (Palmaspis) (Gharib, 1974).A study

28 of the wind effect (Ali, 1989), revealed that the wind in the area plays a major role in the spreading of crawlers of the pit scale insect and congregation of these crawlers on the leaflets on the sides of the tree .The wind direction also explain the north- south spreading pattern of the pit scale insect observed in the Northern State ,Sudan.

2.2.1.5 Geographical distribution Iraq is reported as the origin of The Palmapsis phoneicis (A phoneicis Rao.) and it occurs from Basra to Bagdad (Bodenheimer, 1943). The pest species was reported in Iran in Mohammara and Khuzestan regions (Bodenheimer, 1944). Ezz and Abu El Ezz (1961) examined coccid slides brought from El Hassa in Saudi Arabia which revealed the existence of the pest in Saudi Arabia before 1950 in contrast to the statement of pest existence in Al-Karag area in 1954. Ezz (1973) reported the existence of the pest species at Mallawy and Barragil areas in Egypt, during a survey carried out in 1969 and stated the pest entered this country with date palms originally imported from Iraq and Saudi Arabia in 1929 and this was considered the first record of the species in Egypt. In Palestine, the scale occurs in Bet Shean and Jordan valleys as well as in the Arava area of the Negev Desert (Kehat and Amitai, 1967). Gharib (1974) reported the scale in the districts of Fars, Khuzestan and Baluchistan in Iran. Al-Azawi (1985) reported the species in Qatar on the Kornish date palm and in Um salal Mohamed.

The date palm pit scale was a newly exotic pest in the Sudan ,so it was not reported in earlier studies (Schmutterer, 1969; Nasr, 1982). Its existence in this country was discovered during a survey in 1986. Dowson (1982) reports the occurence of A. phoenicis on date palms in Iraq , Iran , Palastine and Saudi Arabia. The first report of its presence in Sudan dates back to 1989 (Ali, 1989).A recent epidemic spread of this Date Palm Scale insect has been reported from Northern Sudan (by ARC Sudan, March 2003: http:// www . arcsudan. Org / recommendations.htm and Ahmed, 2007).

2.2.1.6 Host plants and economic importance Avidov and Harpaz (1969) stated that the date palm is the sole host of the Asterolecanium phoenicis Rao. Green (1922), Bodenheimer (1943). Büttiker and Krupp (1984) and others reported that the pit scale insect infested the date palm stalks, leaves, leaflets and fruits. The scale causes cholorotic stains that appear on the leaves as a consequence of heavy feeding, the leaves subsequently turn yellow and finally degenerate completely. The insect feeds on the leaflets and fruits covering the date's clusters and shoots (Plate 2) and interferes with natural physiological process such as respiration and photosynthesis (Gharib, 1974).

The pest normally congregates along the veins on the pinnate mainly on the undersurface (Avidov and Harpaz, 1969). The damage to the fruits consists of fouling, which greatly reduces its quality and sometimes renders it unfit for marketing (Kehat and Amitai, 1967). The damage is also reflected in fruit disfigurement and discoloration to the point of culling or reduction in its economic value (Kehat et.al, 1964; Kehat, 1967). The serious attack of this insect is likely to delay the development of the tree leading to tree stunting and may cause its death (Kehat and Amitai, 1967; Kehat, 1967).The date palm, Phoenix dactylifera, is the only host for this pest.

2.2.1.7 Life cycle The available information is on the life-history of the Palmaspis phoenicis Green (Asterolecanium phoenicis Rao) on date palm and on the damage that it causes in Iran, especially in the districts of Fars, Khuzestan and Baluchistan (Gharib, 1974). It feeds on the leaflets and fruits, covering the date clusters and shoots, preventing respiration and photosynthesis. It has two short generations in spring and summer and one long one in autumn and winter. It over wintering as an immature female and pairing occurs in the following May. The female development cycle lasts 85-95 days in spring and summer and 150-180 days in autumn and winter. The males take only 50-60 days to

30 develop, and male flights were observed in May-October. Males form only 25% of the total Palmaspis population in the palms.

In Sudan, the life cycle was studied by Ali 1989; he observed that, the developmental period of the female was longer in winter (80.5 days) than in summer (57.4 days). The duration of the female first nymphal instar was 50 and 45 days in winter and summer, respectively, while the duration of the female second nymphal instar was 27.5 and 4.8 days in winter and summer, respectively. Kehet and Amitai (1967) in Palestine reported that the green pit scale inset, population remained in the second nymphal instar in winter , leading to slow development. Ali (1989) reported the developmental period of the males was shorter in summer (46 days) than in winter (66 days).

Most armored scales have several generations per year, while most soft scales (brown soft scales are an important exception) often have only a single generation. Eggs of both types of scales are usually hidden under the adult female. Eggs hatch into tiny, usually yellow crawlers with legs. Crawlers walk over the plant surface, blown by wind to other trees, or advertently moved by people or birds. Armored scales settle down permanently after a day or two in the crawler stage, moult, and begin to form their characteristic covers. Soft scales move around for a while longer but also eventually settle at permanent feeding sites; half-grown individuals of some soft scale species move once again in fall from leaves to wood for overwintering. Adult female scales are immobile and have a characteristic scale cover. Adult male scales are tiny winged insects that superficially resemble parasitic wasps. They are rarely seen, do not feed, and live only a few hours. Females of many soft scale species reproduce without mating.

2.2.1.8 Management of the pest 2.2.1.8.1 Cultural control Plants need to be provided with good growing conditions and proper cultural care, such as appropriate irrigation, and pruning-off heavily infested twigs and branches, to be more resistant to scale damage (Ahmed, 2003). Plants should be provided with good growing conditions and proper cultural care, especially appropriate irrigation, to become more resistant to scale damage. Heavily infested twigs and branches should be pruned off to eliminate scales when infestations are on limited parts of the plant. Open up trees canopies by prunning in areas of warm- climate, such as the Central Valley of California. Prunning increases scale mortality by exposure to heat and helps to control black scale and possibly other scale species

2.2.1.8.2 Chemical control Chemical control trials against the date palm pit scale insect were conducted in Palestine (Kehat et.al., 1964) and Iran (Gharib, 1974), where the pest caused serious damage to date palms. Other species of the genus Asterolecanium also were reported to be controlled by chemical insecticides in different countries (James, 1932; Morril and Otanes, 1947; Shread, 1960; Kehat et.al. 1964; Gharib, 1974; El-Kifil et.al., 1980).

Kehat et.al. (1964) carried out eight trials in Bet Shean valley in 1959 – 1960. Eighteen different chemical compounds including fumigants, sulphurs, chlorinated hydrocarbons and organic phosphates, were used either alone or mixed with mineral oils and their effects on the different stages of the scale insect were tested. The results showed that the majority of the chemicals were found effective especially against the nymphal stages but didn't prevent the reappearance of the first instars and the renewal of the scale population.

Kehat et.al. (1964) stated that the effective combinations against the date palm pit scale insect in descending order were: 2% Malathion with oil, (special formulation 32 which contains: 712 kg white medium oil, 88 kg technical Malathion, 200 kg water and Emulgator); 0.2% Diazinon 40% W.P. + 2% oil; 0.5% Gusathion 20% EC + 2% oil; 0.5- 1% Malathion 25% W.P. + 2% oil which was the least effective of the above mentioned combinations.

Gharib (1974) reported that the most effective treatment was obtained by Malathion 57% EC at 200 g a.i. /100 liter of water mixed with two liters of volk oil which gave 94.2% mortality. It was followed by Dimethoate 40% EC, Diazinon 25% W.P. and Azinophos-methyl (Gusathion) 20% EC, all at 200 g a.i./100 L of water in combinations with 2 liters of volk oil. This combination gave between 84.2 – 90.4% mortality.

Kehat et.al. (1964) reported that the best time for chemical control in Palestine was during the autumn and winter; when nymphs are more easily controlled than the females. At the time of mass appearance of first nymphal instars during June and July, summer spraying may be necessary to prevent excessive settling of crawlers on the fruits. Kehat and Amitai (1967) reported the best time for control is from November to March when the relatively susceptible nymphs constitute a large part of the population and coinciding with the absence of flowers and fruits that might be damaged by spraying. Gharib (1974) indicated the best times for chemical control in Iran between May – June, November and December, when 75% of the nymphs had left the parent scale.

Chemical control practices were reported against other species of the genus Asterolecanium. Shread (1960) tried granulated systemic insecticides against the scale Asterolecanium spp. Infesting holly plants(Common holly, Ilex aquifolium) where Phorate 2%, Phosdrin 60%, Systam and Disyston were used as soil drenches in 4 inch pots. Phorate and Phosdrin controlled the insect but Disyston and Dystam were inefficient. El Kifil et.al (1980) tested the organophosphorus compounds such as Malathion, Roger, Parathion and mineral oil against the fig scale A. pustulans Ckll, in 33

Egypt. Better results were obtained when the organophosphorus compounds were added to oil than when the oil was used alone. Other chemical control trials were carried out against the other species of the pit scale such as A. coffeae Newst in Kenya (James, 1932), A. bambusae Boisd (Morril and Otanes, 1947), and A. varriolosum Ratz, A. minus Lindinger and A. oercicola Bouche on Oak tree in California (Pritchard and Robert, 1950).

In Sudan, The chemical control attempts were done in the field only against the date white scale Parlatoria blanchardii Targ. , (Siddig, 1975). Petroleum oil at 2%, dimethoate 40% EC at 0.1%, malathion 57% at 0.2%, methyl parathion 48% EC at 0.1% were all tested, alone or in combinations with petroleum oil in a large scale trial in Bauga area. The above chemicals in addition to fenitrothion in oil (Sumifene + oil) 5% and carbaryl 85% W.P., were used in small scale trials. The results of small and large trials showed that the petroleum oil mixed with dimethoate or malathion and methyl parathion alone caused considerable reductions in the populations of the pest. The mixture of Petroleum oil and dimethoate and mixture of Petroleum oil and malathion were recommended for the control of date palm white scale Parlatoria blanchardii Targ in Sudan.

In Sudan, no control trials were carried out against the date palm pit scale insect. Small and semi large scale trials was conducted by Ali (1989) using contact and systemic insecticides and Albolenium oil (alone or in a mixture with insecticides) in El Golid area against the date palm pit scale insect , the results proved that all tested chemicals reduced, the number of the green scale pest and they were significantly different from the control through out the test period, except the Albolenium oil. But no recommendation was reported. The chemical campaign arranged by Plant Protection Directorate, during 1990-1992, with foliar spray ( aerial or ground ) of the chemicals recommended for the white scale and many others compounds , failed to control the pest and the insect spreaded from the target area to other places . A succes

34 full control was achieved by (Ahmed et. a.l ,2003 and Ahmed , 2005 and 2007 ) when he recommended soil application and trunk injection of neonictonids insecticides ,such as imidaclprid as Confidor 200SL ,Comodor 200 Sl ,Rinfidor 200 SL , Attakan and Jugual 200 SL and Thiamethoxam as Actara 25 WG.

According to past chemical control undertaken in Iran, the best times for chemical control were found to be May-June, November and December, when 75% of the nymphs had left the parent scale; the most effective treatment was 57% malathion at 200 g/100 liters, which gave 94.2% mortality, followed by 40% dimethoate (Roxion), 25% diazinon and 20% azinphos-methyl (Gusathion), also at 200g, and emulsifiable Volck oil at 2 liters/100 liters. All of these gave 84.2-90.4% kill (Gharib., 1974). Soil application of the insecticide imidacloprid provides good control with least environmental impact (Ahmed, 2003).

An oil emulsion spray in spring and another in autumn kills the crawlers of the white scale insect and prevents the development of severe infestations (Kehat et.al. 1974). Infestations on small to medium-sized trees can be adequately managed with one annual application over several consecutive years. Insecticidal oil should be diluted to a solution of 1.5 to 2% (1.5 to 2 parts oil to 100 parts water). When leaves are on the tree, it is too difficult to get the degree of coverage needed for oil treatments to be effective.

Mixtures of oil and organophosphate insecticides applied in spring to kill hatching crawlers are not recommended because of the environmental hazards associated with applying these insecticides to large trees especially in residential areas, the difficulty of getting adequate coverage with available application equipment, and the availability of safer, more effective alternatives ( Ahmed,2007). Application of alboliunium oil (Ali, 1989) and Chlorpyrifos (Ahmed, 2007) are not effective against the adults of the green pit scale under Northern State condition.

2.2.1.8.3 Soil application with Neonictonoids insecticides (Thiamethoxam and imidacloprid) Relatively new classes of insecticides, the neonicotinoids (also called chloronicotinyls, or nicotine mimics) provide a useful alternative to the traditional foliar insecticides such as synthetic pyrethroids or carbamates, (Castle et.al, 2005). The neonicotinoids, the newest class of insecticides, have outstanding potency and systemic action for crop protection against piercing-sucking pests. Their common names are Acetamiprid, Clothianidin, Dinotefuran, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam (Tomizaw and Casida, 2005). This class of insecticides has several advantages. Because of the systemic activity when applied to soil or seed, these products are taken up through the roots and transported into new leaf tissue where they persist through the critical early plant stages. They can be applied in the furrow or as a surface band at planting, which simplifies control efforts especially in fields. They can be applied through drip irrigation, which allows application to be timed shortly in advance of the expected arrival of the pest, and is suited to crops grown on plastic. They can be applied as a transplant drench prior to setting out in the field. Also, they are very well suited to a perimeter trap crop system – which dramatically reduces the cost per acre for pest control. .

The neonicotinoids generally have low toxicity to mammals (acute and chronic), birds, and and fish. (Prabhaker et. al, 2006 and Wu et. al, 2006) Biotransformations involve some activation reactions but largely detoxification mechanisms. In contrast to nicotine, epibatidine, and other ammonium or iminium nicotinoids, which are mostly protonated at physiological pH, the neonicotinoids are not protonated and have an electronegative nitro or cyano pharmacophore. Agonist recognition by the nicotinic receptor involves cation-π interaction for nicotinoids in mammals and possibly a cationic subsite for interaction with the nitro or cyano substituent of neonicotinoids in insects. The low affinity of neonicotinoids for vertebrate relative to insect nicotinic

36 receptors is a major factor in their favorable toxicological profile. (Drinkwater, 2003; Castle et.al, 2005 and Tomizawa and Casida, 2005).

Thiamethoxam is the first commercial neonicotinoid insecticide from the thianicotinyl subclass. Novel variations of the nitroimino-heterocycle of imidacloprid led to 4- nitroimino-1, 3, 5-oxadiazinanes exhibiting high insecticidal activity. Among these, thiamethoxam (CGA 29433) was identified as the best compound and selected for worldwide development (Nauen et al, 2002 and Salas and Goane, 2003). The compound can be synthesized in only a few steps with high yield from easily accessible starting materials. Thiamethoxam acts by binding to nicotinic acetylcholine receptors. It exhibits exceptional systemic characteristics and provides excellent control of a broad range of commercially important pests, such as aphids (Aphis fabae, Aphis gossypii, Myzus persicae, Brevicoryne brassicae, Nasonovia ribisnigri, Macrosiphum euphorbiae and Acythosiphon solani [Aulacorthum solani]), jassids (Empoasca devastans [Amrasca biguttula biguttula] and E.lybica [Jacobiasca lybica]), whiteflies (Bemisia tabaci, Bemesia argentifolii and Trialeurodes vaporariorum), thrips, rice hoppers (Nilaparvata lugens), Colorado potato beetle (Leptinotarsa decemlineata), flea beetles (Phyllotreta and Chaetocnema spp.) and wireworms (Agriotes, Melanotus and Somaticus spp.), as well as some lepidopteron species (Maienfisch et. al ,2001;Nauen et.al,2002; Yamamoto et al , 2002 : Pettis et. al, 2005 and Perovic et al ,2006) . In addition, a strong preventative effect on some virus transmissions has been demonstrated (Wilde, 2004). Thiamethoxam had been developed for both foliar and soil applications and for seed treatment for use in most agricultural crops all over the world. Low use rates, flexible application methods, excellent efficacy, long-lasting residual activity and favourable safety profile make this new insecticide well-suited for modern integrated pest management programmes in many cropping systems

The efficacy of imidacloprid (0.35, 0.70 and 1.05 g a.i./plant) and thiamethoxam (0.25, 0.50 and 0.70 g a.i./plant) in controlling citrus leaf miner (P. citrella) infesting lemons was determined by a field experiment conducted in Argentina. Application of 0.35 g a.i. imidacloprid/plant and 0.25 g a.i thiamethoxam/plant controlled citrus leaf miner up to 100 days after planting (Salas and Goane, 2003).

The efficacy of insecticides from the neonicotinoid group in controlling the citrus leaf miner, P. citrella infesting mandarin cv. Chahara variety was determined in an experiment conducted in 2002 and 2004 (Perovic et al , 2006). The following insecticides were applied as foliar spray: Confidor 200 SL (imidacloprid), Actara 25 WG (thiamethoxam), Mospilan 20 SP (acetamiprid), Calypso 480 SC (thiacloprid) and Dynamec (abamectin) + Coccidol E (mineral oil). The effects of the insecticides were assessed 1, 14 and 21 days after treatment. The efficacy of the applied insecticides was high 7 days after the treatment. Mospilan 20 SP (0.025 and 0.05%) and Dynamec (0.05, 0.075 and 0.1%) + Coccidol E (0.5%) recorded high efficacy 14 days after the treatment. On twenty-first day, the efficacy of the insecticides was low.

A study was conducted to compare the efficacy of neonicotinoids and conventional insecticides on cotton crop in Multan, Pakistan, for cropping years of 2002 and 2003 against cotton jassid, Amrasca devastans [A. biguttula biguttula] and whitefly, Bemisia tabaci. Diafenthiuron, acetamiprid, imidacloprid and thiamethoxam proved to be the most effective in reducing jassid population below ETL (1-1.5/leaf) upto seven days after application during both the years. The efficacy of thiomethoxam (25, 50, 75 and 100 g/ha) in controlling A. barodensis infesting sugarcane was determined and compared with those of 50 g imidacloprid/ha and 750 g dimethoate/ha in a field experiment conducted in Lalapettai and Saptur districts in Tamil Nadu, India. The efficacy of thiomethoxam against the pest increased with increasing the rates of insecticide.

Experiments were undertaken in Gavião Peixoto, Sao Paulo, Brazil, in 2003-04 (Filippe et. al, 2005) to evaluate the efficacy of systemic insecticides for control aphids and leafhoppers on young citrus plants ('Pera' grafted onto 'Sunki' mandarin) after application in the nursery followed by planting in the field. In a first experiment, the application was carried out in the nursery, by drench, using 20 ml of solution/nursery tree. Thiamethoxam WG (1.0, 1.2 and 1.6 g CP/nursery plant), imidacloprid GrDA (0.25, 0.5, 0.75 and 1.0 g CP/nursery plant) and imidacloprid CS (1.75 and 2.6 ml CP/nursery plant) were tested and compared with thiamethoxam GR (25 g CP/nursery plant). The insecticides effectively controled the leafhopper Oncometopia facialis and the brown aphid Toxoptera citricida [T. citricidus] for 155 and 90 days, respectively. In a second experiment, the insecticides were applied in the field, by soil (granular) and by drench (50 ml of solution/plant). The control periods of O. facialis by aldicarb+imidacloprid (10+0.5, 10+0.7, 15+0.5 and 15+0.7 g CP/nursery plant), thiamethoxam GR (30 g CP/nursery plant) and thiamethoxam WG (1.2, 1.6 and 2.0 g CP/nursery plant) reached 120 days approximately. However, aldicarb alone (15 g CP/nursery plant) gave a shorter control period. For aphids, until 61 days, the control was over 95% in all treatments. There was no occurrence of this pest in further evaluations. In conclusion, it is important to apply insecticide in nursery trees, in screen house, and it is recommended to perform another application in the field after 90 days.

2.2.1.8.4 Trunk injection Tree injection has been practiced as early as the 12th century, when Arabs described methods for introducing solid substances into holes or cuts in plants for imparting perfumes and medicinal qualities to fruits, or colors to flowers. Later, Leonardo da Vinci was, apparently, the first person who developed systematic experiments with liquid injections into trees (Roach, 1939).

Numerous injection experiments were carried out, and a compilation of works to the beginning of the 20th century was made by Roach (1939). The development of systemic fungicides renewed interest in tree injection in the 1970s (Kielbaso et. al., 1979). Today, tree injection is an alternative method of chemical application with the following advantages: (1) efficient use of chemicals, (2) reduced environmental contamination, (3) applicable when traditional soil and foliar application methods are either ineffective or too difficult, and (4) acceptable in populated areas.

Several injection methods, including bark banding (Koehler and Rosenthal, 1967), trunk infusion (Schreiber, 1969), and pressurized trunk injections (Filer 1973; Heiburg et al. 1973; Reil and Beutel, 1976 and Oihabi, 2003), were developed in the second half of the 20th century. Low-pressure trunk-injection methods, working at pressures below 100 kPa, described by Darvas et. al. (1984), McClure (1992), and Navarro et. al. (1992), are currently popular because special equipment is not required and solutions are distributed efficiently. These injection methods differ in terms of ease of use and application cost. The method described by Navarro et al. (1992) is widely used in Spain with positive results for treatment of tree pathogens (Fernandez-Escobar et. al., 1994and 1999), tree insects (Fernandez de Cordova and Gallego, 1997), and nutritional disorders (Fernandez-Escobar et. al., 1993).

The pesticide injection techniques are widely documented by several workers, Al- Jboory et al (2001) detected Thiamethoxam in date palm leaves at 24 hr post injection of 1g a.i./plant and the insecticide persisted for considerable period; suppressing the population density of old world bugs significantly. Fernandes and Gallego (1997) found that oaks infested by oak scale insect were cured by injection with prepared capsules of 225ml acephate or imidacloprid solution, these insecticides were effective in the controlling the scale pest, moreover, they pointed out that grater than 79% control of oak scale was obtain when acephate and midocloprid were injected at rates of 7.5g a.i. and 0.8ml pre tree respectively. 40

In addition to the injection system, other factors influence the uptake and distribution of injected substances in tree trunks. These factors are related to the technique used (Nyland and Moller, 1973; Sachs et al., 1977; Sanchez-Zamora and Fernandez- Escobar 2000), the chemical injected (Reil 1979; Guest et al. 1994), the plant species (Sachs et al. ,1977; Sanchez-Zamora and Fernandez-Escobar,2000), the environmental conditions (Reil and Beutel 1976; Reil 1979; Sanchez-Zamora and Fernandez-Escobar ,2000), the phonological state of the tree (Reil ,1979; Whiley et al., 1995; Sanchez- Zamora and Fernandez-Escobar ,2000), and tree health (Sachs et al. 1977 and Lewis

1979).

2.2.1. 8.6 Biological control Scales are usually controlled by natural enemies, including many species of small, dark, lady beetles, Hyperaspis species which are tiny, shiny, black lady beetles with several red, orange, or yellow spots on the back. Rhyzobius lophanthaes is a lady beetle with reddish head and underside, and a grayish back densely covered with tiny hairs. The twice stabbed lady beetle, Chilocorus orbus, is shiny black with two red spots on its back, and reddish colour underneath. The larvae of certain predaceous lady beetles can be found under the female of soft scales feeding on scale eggs and crawlers.

Many parasitic wasps are important natural enemies of scales, such as Aphytis, Coccophagus, Encarsia and Metaphycus. Parasite activity can be estimated by checking scale covers for the round exit holes made by emerging adult parasites. Covers of armored scales can be removed to examine immature parasites beneath. Grow flowering plants near scale-infested trees and shrubs to help augment natural enemies (Zaid and arias, 1999).

None of the natural enemies associated with the scale Asterolecanium phoenicis Rao., were reported before 1967, even in catalogues of parasites and predators (Thompson, 41

1950; Thompson and Simmonds, 1964). Kehat (1968) reported that females of the pit scale, Asterolecanium phoenicis Rao. were highly resistant to attack by the coccinellid predator, Pharoscymnus numidicus Pic,espeically larvae and adults, apparently due to their hard scale coverings, whereas nymphs were devoured readily. Yinon (1969) reported that the Asterolecaniids, the soft scales, the mealy bugs in addition to the armored scales, constitute the host range of the Coccinelled predator, Chilocorus bipustulatus L.

The intensity of predation on of the Asterolecanium phoenicis Rao. was only one-third the intensity of predation on the armored scale insects (Yinon 1969). The presence of the parasitoid Habrolepis dalmanni (Encyrtidae) resulted in the virtual elimination of golden oak scale, Asterolecanium variolosum, a closely related species, in New Zealand. The coccinellid Chilocorus cacti , has been successfully introduced to control Asterolecanium bambusae (bamboo scale) and Asterolecanium pustulans (oleander pit scale) in other countries.

2.2.1.9 The situation of the green date palm pit scale insect in Sudan Palmaspis phoenicis [Asterolecanium phoenicis] was recorded on date palms in the Sudan during 1986-87 for the first time. (Ali and El-Nasr, 1992) The pest was first reported in El Golid area through illegal introduction of some offshoots from Saudi Arabia in 1974. Later, the pest crossed the natural barrier of Baja desert to invade Elgaba scheme, (150 km south of Dongola, 400km-north of Khartoum). In 1996 it became a real threat to date palm cultivation in Northern Sudan (Ahmed et. al., 2002). The infested area in El Golid, Elgaba and Old Dongola reached about 5000 hectares, extending over 60 and 50 kilometers along the west and east banks of the Rver Nile respectively. The newly reported infestation in Artigasha Island, Orbi and EL Burgig Scheme in Dongola area and Abuhamad in the River Nile State (23000 infested palm trees) is evidence that, the pest is still in its rapid spread. The total number of infested trees is about one million (Ahmed, 2005)

In the past, and due to lack of indigenous knowledge of appropriate control measures, the control efforts were not successful; hence the level of infestation steadily increased. The insect attacks the leaflets, leaf rachis and fruits. It causes chlorosis, degeneration of the leaves, malformation of fruits before maturity leading to losses in production from a range of 30-50 kg to 5 kg per tree (Ali and El Nasr, 1992). The losses may range between 85 and 90% according to the infestation rate, variety infested and management conditions (Ahmed, 2001 and 2004)

Studies have been conducted on the biology and population development of the pest, its seasonal abundance, susceptibility of date palm varieties, losses caused by the pest, and on control methods (Ali, 1989). An eradication program was attempted based on pruning, local quarantine and aerial insecticide application. Insecticide applied, at spray volumes of 100 liters of water, were diazinone 60 EC (340 ml), Roger 32% EC (225 ml), and Folimate 80% (200 ml); each including 2 liters of 80% Albolinium oil. A 96.4% control rate was achieved, thus lowering the infestation within the targeted area drastically to 3.6% and ended nearly in curtailing apparently its infiltration outside the infested area. The infestation had flared back to more than 50 % in less than one year. Eradication of the insect was doomed to failure. Attempts to locate a biological control agent failed when a Coccinelid beetle was introduced (Ali, 1989). Results from research conducted in Dongola Research Station, indicate that, this pest can be controlled using an IPM package including; cultural, chemical and biological control measures. The systemic insecticide used for this purpose was Confidor 200SL (imidacloprid) (Ahmed et .al, 2002)

2.2.1.10 Varietal susceptibility A study has been conducted by Ahmed (2000) in Elgaba scheme, Northern State, Sudan to evaluate the susceptibility of four date palm varieties (Barakawi, Gondiella, Moshrig /Wadlagai and Jaw) to green pit scale insects. Results indicated that, the order of susceptibility among the cultivars was highest in Gondeilla,

Barakawi, Jaw and the cultivar Moshrig/ Wad Lagii was the least susceptible .Similar result was obtained by Ali (1989) in ElGolid area where, the varietal susceptibility studies showed that Moshrig and Gondeilla varieties were the most susceptible . Barakawi was moderately susceptible while Jaw and Tamoda were the least susceptible according to average number of scales per leaflet.

2.2.2 White date palm scale The white scale, Parlatoria blanchardii Targ., is widely present in most date palm growing areas of the world except in USA, where it was eradicated in 1936 (Zaid and Arias,1999), and in some countries of the southern hemisphere {Namibia and Republic of South Africa (RSA)}.It is considered a serious pest in Algeria, Kuwait, Libya, Mauritania, Morocco and Tunisia. Iraq, Oman, Saudi Arabia and Sudan consider this pest a moderate one, while Egypt, Jordan, UAE and Yemen consider it a minor pest. Damage by white scale is very serious on young palms between two to eight years of age, but even under severe attacks, the palm and its offshoots do not die. Nymphs and adults suck the sap from the leaflet, midribs and fruits. Under each scale insect, a discolored area appears on the leaflet. Heavy infestation causes a leaflet to turn yellow and contributes to the premature death of the fronds (Mohamed, 1991).Respiration and photosynthesis are almost stopped resulting in early death of the infested leaf. Damage on fruits is easily noticeable and the production is not marketable. The number of generations developed during one year varies from three to four depending on temperature. The natural enemies of Parlatoria blanchardii are: Hemisarcoptes malus, Chrysoperla vulgaris, Cardiastethus nazarenus, Coccinellidae (29 species), Nitidulidae (5 species), Mycetaeidae (1 species), Aphytis mytilaspidis, Cybocephalus nigriceps, Cybocephalus rufifrones, Chilocorus bipustulatus var. iraniensis and Chilocorus sp. (FAO, 1995). Natural enemies and pruning normally keep pest populations at tolerable levels. In the 1970s the coccinellid Chilocorus bibustulatus var. iraniensis was introduced into Mauritania and Morocco, but permanent establishment failed and efforts were discontinued. In the 1980s, attempts

44 were made to introduce the coccinellids into northern Sudan, but they were not successful either (Ali, 1989). In 1993 the coccinellids were released in Oman, but there is no information on their establishment (FAO, 1982 and 2002). The introduction of coccinellids is currently being investigated in Tunisia. Chemical control appears to be conducted occasionally in young plantations using mineral oils (Djerbi, 1980).

Parlatoria date scale is found wherever date palm is grown in Sudan. But it causes severe damage in the southern parts of the Northern State and in the River Nile State. It mainly infests the leaves, where the nymph sucks the sap and finally the leaves are covered with white scales and dry out. In heavy outbreaks, fruits may be attacked and fall off before maturity. According to Ali (1989), varietal susceptibility experiments showed that Mishrig and Gondeilla were the most susceptible varieties. The infestation on the varieties Brakawi and Jaw were moderate while Tamoda was the least affected variety.

Some work has been carried out by Siddig (1975) for control of this insect. He reported that removal of infested lower leaves of date palm was found as effective means of decreasing infestation by the insect. Spraying with petroleum oil plus, dimethoate (Roger) also resulted in significant control. A survey in North Sudan (Harten and Abdelrahman, 1996) has proved that populations of Parlatoria blancharidii (Targ). , are normally kept at tolerable levels by indigenous natural enemies such as larvae and adults of a brownish ladybird Pharosscymnus sp. ,(Coccinellidae),Cybocephalus dudiclri(Nititulidae),Crysoperla carnea(Chrysopidae) , Archenomus arabicus(Aphelmidae), and some un identified mites. An introduced predator, lady bird, Chilocorves bipusrulatus var. iransis was applied also to control the pest but with little success due to the unsuitable climatic conditions or some other ecological factors.

2.2.3 Red scale Red scale, Phoenicococcus marlatti. Cockerell is exclusively a pest of palms, particularly date palms, with other palms as host plants (e.g.: Doupalm, Canary Island palm and the California fan palm). It is probably found wherever date palm is cultivated, but with no great threat (Dowson, 1982). The extent of its damage is known to be less than that caused by the white scale.

Leaves of date palm are often found to be clotted over with thin, minute, grayish scales with darker centers. The darker spot is oval in outline and is the body of the insect itself. The individual scale is seldom larger than a small pinhead, round in shape, and deep pink to dark red in colour, but partly or entirely covered with a white waxy secretion that forms a cottony mass (Nixon and Carpenter, 1978).

All exposed portions of the palm can be attacked by the pest. Heavy infestations could cause complete coverage of the leaf surfaces by scales, which will result in interference with the metabolic functions of the plant. Attacked leaves and underlying tissues may be damaged to a depth of a few millimeters and will consequently be killed in severe cases.

The red date scale usually stays out of the light and is found massed on the white tissues at the bases of the leaves and fruits stalk, where it is protected by fiber and other leaf bases. Frequently, the scale is found on roots underground. The red scale is not as easily detectable as most other scales because of its natural tendency to hide. Red scale is not suspected until the base of the green leaf is cut and subsequently observed. Stickney et. al. (1950) provided a comprehensive study of the insect's biology. P. marlatti. , passes its life cycle in a protective covering of wax it secrets. The female produces numerous eggs under the protective scale. After the eggs hatch, the nymphs crawl out and move about freely, feeding at various positions. Once a suitable location on the host plant is selected, nymphs insert their needle-like mouth

46 parts in the plant tissue to suck the sap. When they start to feed, layers of wax, forming the covering of the scale over the body, are secreted. Soon after beginning to feed, adults will moult. Later on, males are incapable of feeding and mate with the females and die. The female, once fertilized, increases rapidly in size and produces eggs before dying within the scale.

The pest breeds actively during the summer months and hibernation starts in early winter. A complete life-cycle takes approximately 55 days during summer and 158 days during winter. Three to five generations could be found annually (Stickney et. al., 1950).

It is worth mentioning that the scale appears to cause considerable damage to plants growing under favorable conditions. Areas where the climate is milder or more humid may also face severe scale attacks.

Even though this scale insect is regarded insignificant, and with no economic impact, the first measure is to cut away all attacked leaves and burn them in order to stop the spread of the pest. Infested palms, offshoots or even tissue culture-derived plants, which are still at the hardening phase, must be sprayed with Malathion 370 - 450 g or with parathion 120 g a.m. dissolved in 450 liters of water (Zaid and Arias, 1999).

Since the scale is a sucking insect, the use of ultracide or dimethoate when the pest is mobile is also recommended (Djerbi, 1980). Infested offshoots could also be subjected to a temperature of 50°C for 65 hours in an insulated room. General predators, such as Pharoscymnus anchorago (Fairmaire), are considered as active predators.

2.3 Other major insect pests of date palm 2.3.1 Caroub moth Caroub moth, Ectomyelois ceratoniae. Zeller is found in all date growing areas. The larva of the Caroub moth attacks dates in plantations, packing houses and stores. Eggs are laid on the dates and hatching begins four days later. The larval period is about three weeks in warm months and eight weeks in colder months. The pupal period is about five days. Taking into account the moth's life cycle, it is recommended to protect the fruit bunches, to clean the plantation from wind-fallen fruits and to fumigate harvested and stored dates. The use of pheromone traps will not only help to determine the emergence of moths but also to estimate the population level. The rate of infestation could be lowered by spraying the infested fruits with Bacillus thuringiensis (Djerbi, 1980).

2.3.2 Rhinoceros beetle (Oryctes rhinoceros Linné) The adult beetle is a stoutly-built insect about five centimeters in body length and shiny black in colour with a reddish under-surface covered with short, fine hair. Its tibiae are furnished with thorn-like spines. This insect has earned the name of rhinoceros beetle because of the presence on its head of a horn-like structure, which is conspicuously longer in the male.

The adults feed on tender leaves, inflorescences and fruit stalk of the fruit bunches of date palm whereas the grubs thrive on decomposing dung and decaying vegetable matter like stumps and trunks of palms. This insect is also a pest of coconut and other palms (Aisagbohni 2003).Within a week of their emergence female's start laying eggs. The whitish-brown eggs are laid singly in dung heaps and decomposing vegetable matter. The eggs hatch into fat soft-bodied pale-yellowish curled larvae in 10 to12 days. The larvae become full-grown in about 4 or 5 months and they take another 6 to 7 months in hibernation before they transform into pupae. The full-grown larva is a stout fleshy creature measuring about 7 cm in length with brownish head and dirty

48 white appearance. The full-fed grub pupates in the dung heaps, in a specially prepared oval chamber made of soil or excretory matter. The adult beetles emerge from the pupae in about 3 to 4 weeks and fly to nearby palms and start feeding on them causing damage. There is only one generation during the year.

Contrary to other pests, only the adult beetles are responsible for causing damage to the palms. The pest has been found to be more destructive to young plants (FAO, 2002). They remain hidden during the daytime and become active at night, when they fly about and reach the tops of date palms. They drill large holes close to the base of the growing heart-leaf and enter the stem. They feed on the softer tissues of the growing heart-leaf and cut right through it, with the result that further growth stops and the palm ultimately dies. The beetle also causes damage by boring into tender fronds, chewing tissues and throwing them out as a fibrous dry mass. Fronds may hence break and if the growing point is bored the plant dies off. Most of the damage occurs during the rainy season (Aisagbohni 2003).

The adult beetles should be attracted and destroyed by putting up mercury-vapor light traps at regular intervals in infested plantations.

2.3.3 Red palm weevil The red palm weevil, (RPW), Rhynchophorus ferrugineus Oliv. , also called the Indian palm weevil, is well known in the Middle East where it causes severe damage on date palms. The RPW was first noted in the Arabian Peninsula in the mid 1980's and in Egypt in 1992. The weevil was first observed in Rass El Khaima, United Arab Emirates in 1985. Approximately, 5 to 6 % of palms in the Middle East region are infested with the RPW with an annual rate of infestation of about 1.9 (Abraham et. al., 1998; FAO, 2002; Bream, 2003 and Oehlschlager, 1998 and 2007)

2.3.4 Desert Locust (Schistocerca gregaria Forskal) The desert locust occurs in all date growing areas of the Near East and North Africa and causes severe damage. Heavy migrations into date plantations are sporadic but may be devastating. The locust feeds on leaves and fruits of the date palm and may destroy the palm's canopy and leave the palm totally naked .Young locusts feed on younger plants and small offshoots.

Swarms of locusts are usually measured in terms of square miles and occur throughout the date-growing areas (Djerbi, 1983a).To recover from a severe locust attack, a date plantation needs at least three years - under optimal growing conditions - to reconstitute its canopy. The use of aerial spraying on both ground and flying swarms of locusts has been successful since 1959.

2.3.5 Termites (Odontotermis smeathmani) Termites usually feed on cellulose matter and the attack starts from the root zone and base of the offshoots by making vertical tannel through it, or building soil- canals on it, allowing them to reach the stem. Termites usually cause the death of newly planted offshoots. They may also make galleries in the trunks of weak palms and cause them to collapse. Control measures could be started by removing and burning destroyed offshoots. In case of a slight attack, it is recommended to clean the offshoot of soil tannels and spray with a termite killer (Dursban or Hostathion). It is also advised to turn over the surrounding soil to about 50 cm deep in order to destroy these canals and treat them with a termaticide product (which will certainly kill all termite species).

Termite damage to date palms in Northern Sudan has been recorded since the 1920s and has been recognized as a serious problem by several authors (Schmutterer, 1969; Ali 1989; Logan, 1993 and Ahmed, 2003).Obied (1987), reported that 60% of date palms in Northern Sudan were attacked and 35% were seriously affected, and an annual loss of 1-2% of trees was estimated. 50

Odontotermis smeathmani is mostly observed in all parts of the Northern Sudan. Termites primarily attack the dry plant parts which include the fiber and the leaf axis; this infestation usually starts on the soil surface and goes as high as 20-30 feet along the stems of some palms (Nixon, 1967). Severe termite infestation may gradually weaken the stem resulting in complete destruction of the tree.

2.3.5.1 Termites Control It was recommended by Nixon (1967) that old leaves should be cut out close to the trunk at least four or five feet above the ground. With regards to chemical control it has been practiced in very small and confined areas using Dieldrin and Chlordane which are banned and no longer recommended due to the hazards which they present to both environment and human health. So investigation for appropriate cost effective alternative measure is required using other chemical compounds, such as, Marshal Suscon 109, Furidan 5g. and imidacloprid (Ali and Tibbin, 1992 and Ahmed et. al., 2002) were recommended as alternatives.

2.3.5.2 Termite’s natural enemies After leaving the nests the winged forms of tremites are preyed on by lizards, frogs, birds, bats and other natural enemies. Among the insects several ant species e.g., Oecophylla longinoda (Latr) and Paltothy reustarsatus (F) are most effective predators.

2.3. 6 Store Pests. They include; the raisin or stone moth Ephestia sp: Lepidoptera, the saw grain beetle Coleoptera, Oryzaephilus surinamensis L. According to FAO (1982), the infestation of store pests sets in shortly after harvest and by the following year as much as 50 percent of the stored dates are completely destroyed and the remainder is hardly fit for consumption.

Dates can be protected by early harvest; clean packing, avoidance of mixing of the fruit drops with any harvest, and immediate fumigation. Fumigation is usually effective by use of phostoxin tablets.

2. 3. 7 Greater Date Moth (Arenipses sabella Hampsim): Lepidoptera: Pyralidae. Few incidences of infestation were reported from Gorair area in the Northern State. The insect was successfully controlled by dusting with Sevin 85%.Dusting was carried out on tops of trees during flowering and very early after fruit setting (Obied, 1987).

2.3. 8 Minor insect pests of date palm Because they are pests and/or do not cause damage of economic importance (Hussain, 1974, Djerbi 1983b and FAO 1982 and 2002), the following pests are not detailed in this review, but are listed in (Appendix: 6).

2.4 Other pests of date palm 2.4.1 Bou Faroua (Old World date mite) Bou Faroua also called Goubar or Old World date mite. It includes Oligonychus afrasiaticus McGregor and O. pratensis Banks. This mite is present in all date growing areas, and damage is severe in neglected plantations. Immediately after fruit set (Hababouk stage) mite eggs are deposited to produce larvae which feed on the fruits and later cover these with a web which retains sand particles. The cycle length is about ten to fifteen days depending on temperature. Mites rapidly multiply causing the drop of the fruits. Affected mature fruits are of no commercial value.

Chemical analysis of infested and fully mature dates showed that the water soluble substances such as sugar were less in infested dates (Hussain, 1974). Under Iraq's climate, the old world date mite has six overlapping generations during the fruiting season of palms (Hussain, 1974). The mite population on dates reaches its peak during the middle of July. The first appearance of mite on immature dates is during the first 52 week of July. Even though they are found on all parts of the date, the majority of mites congregate near the calyx area, where most of the eggs are laid. Mite and eggs are also found on fruit stalks. The mites migrate to the palm crown during the last week of August. Hussain (1974) stated that the fibers and frond bases taken from infested palms during the winter months show adult and nymphs. This mite does not hibernate on the leaflet, date palm seedlings, and offshoots or on other vegetation in the plantation. Dusting date bunches early in July with sulphur at the rate of about 100 - 150 g per palm is effective (Zaid and Arias, 1999). The Iraqi variety "Sayer" is relatively resistant to mite attack.

The date mite is observed on palm all over the country. Occasionally serious damages are found in palm with close spacing or that intercropped with citruses or mangoes. The mite usually feeds on the fruit at kalal and rutab stages resulting in rough silvery surfaces. Severely infested fruits stop to expand and do not mature properly. Dusting with sulphur towards the end of May or the first week of June recommended.

2.4 .2 Nematodes Root-knot nematodes (Meloidogyne spp.) are widely distributed in date palm plantations, but the amount of damage caused to fruit bearing palms has not been determined (Carpenter, 1964). Nematodes are spread most readily by offshoots. When grown below the soil surface, an offshoot may be infested while attached to the mother palm. Nurseries provide a second source of infestation of offshoots. Root-knot nematodes have such a wide range of cultivated and weed hosts that their control in date plantations has not been attempted. Nematodes in the date palm plantations do not appear to have been studied before 1965 (Dowson and Pansiot 1965). It is possible that much of the unhealthy growth of palms, generally attributed to other causes, may be due to nematode attack.

2.5 Diseases of date palm Many date palm diseases were reported and summarized in table (1) below (Fawcett and Klotz. 1932; Klotz, 1932; Bliss, 1937and 1944; Nixon, 1932 and 1951and 1954; Calcat, 1959; Darley et al. 1960; Mohamed and Al-Haidari, 1965; Hussain, 1974; Thomas, 1974; Carpenter, 1975; Al Hassan et. al., 1977; Djerbi, 1983 (a and b); FAO, 1982 and 2002, Obied, 1987and Ali et.al, 1998).

In Sudan, little has been formally published regarding diseases of the date palm. In 1987 survey of date palm diseases was conducted by the Plant Pathology Department of the Plant Protection Directorate - Khartoum North. (Obeid, 1987). Then another survey was done jointly with the help of FAO expert with same Department (Logan, 1993). The survey revealed the presence of the many diseases along the banks of the Nile, between Dongola, Marawi and Karima. Similar symptoms to Bayoud disease (False Bayoud) such as whitening of the middle crown leaves, most of leaves take the albino white colour were observed. The rachis of affected frond remains green. This phenomenon occurred sporadically in some locations (ELHassan, 2006) .The second disease was Slow Decline, it is characterized by yellowing followed by drying and death of leaflets tips. Pineae die at the tips of leaves and tips of pineae die along the rachis for about 1/2-2/3 length from outer. White chlorotic or brown streaks frequently extended longitudinally down side of rachis. The disease is dominant all over the region and most serious because it is lethal. The third disease was the White Tip Die Back and this might be pattern of slow decline. The causal organism for these diseases not yet verified because Koch's postulates have not been fulfilled. However investigation at Rothamstead Research Laboratory in the U.K. showed particles of a virus-like organism (Mycoplasma) for both slow decline and white tip die back, it has been assumed to be particles similar to what is found in the yellow disease of coconut. Mycoflora of Date Palm was determined in Northern State of Sudan. Fungi associated with some pathological symptoms were defined as follows: 1. Fusarium moniliforme known to cause inflorescence rot.

2. Mauginiella scaette known to cause inflorescence rot. 3. Thiolaviopsis paradoxa known to cause Majnoon disease. 4, Aspergillus sp. known to cause fruit rot. 5. Alternaria sp. known to cause fruit rot. 6. Helminthospor-ium sp. known to cause fruit rot

Also viral symptoms, Fletrissment occurring in Tunisia were suspected to be prevalent, in Sudan in some places in the Northern Province. On the other hand, eight genera of plant parasitic nematodes were extracted from the soil taken from the palm rhizosphere. These were: Psilenchus sp., Tylenchus sp., Tylenchorynchussp Paratylenchus sp., Tylenchulus semipenetrans, Trichodorus SP., Longidorus sp, Xiphinema sp. The later three nematodes are known to be vectors of plant viruses. It should be noted that date palm grown was impaired by close spacing, lack of proper and regular pruning, no fertilization, improper irrigation, water stress and water logging. This was due to drought spells which wiped out the region early in 1980's followed flooding for prolonged time (1-2 month in 1985-1988-1990 and 1999) .This might changed the ecosystem of plant growth and rendered them to be sensitive to different pests and diseases as appeared now.

Table (1): Date palm diseases and their occurrence in Sudan

Disease Causal organism Occurrence in Sudan

Fungal diseases 1- Bayoud disease Fusarium oxysporum f. sp. albedinis - 2- Black scorch disease Thielaviopsis paradoxa + 3- Brown leaf spot. Mycosphaerella tassiana (De Not) + 4- Diplodia disease Diplodia phoenicum (Sacc) + 5- Graphiola leaf spot Graphiola phoenicis (Moug) + 6- Khamedj disease Mauginiella scattae Cav. + 7-Omphalia root rot Omphalia tralucida Bliss + 8- Belâat disease Phytophtora phoenicis (Moug) + 9- Fruit rot Aspergillus niger + Phytoplasmic diseases 1- Lethal yellowing Mycoplasma-like organism - 2- Al Wijam Mycoplasma- like organism + 3- Brittle leaves disease Mycoplasma- like organism + Diseases of unknown cause 1 -Bending head Unknown cause + 2- Dry bone Uknown cause - 3- A round disease Unknown cause - 4- Rhizoids Unknown cause - Physiological disorders 1- Black nose Humid weather at the Khalaal stage - 2-Crosscuts Anatomical defect - 3-White nose Dry and prolonged wind in the Rutab - 4- Barhee disorder stage Physiological disorders - 5- Black scald Exposure to high temperature - 6- Bastard offshoot Growth regulators + 7-Leaf apical drying Injury of date palm root system + 8- Fertilization injury Fertilizers applied close to the palm's + 9-Frost damage When temperature falls below 0° - 10- Lack or excess of water Water variations. +

(+: found in Sudan, -: not found)

3: MATERIALS AND METHODS

3.1 Chemical Control A series of small scale experiments were carried out at Elgaba scheme and El Golid area during the seasons (2003/2004- 2004/2005) to evaluate the efficacy of four systemic insecticides (belonging to the new group of inecticides, neonictoniods ) against the green date palm pit scale insect using two application techniques(soil application and trunk injection). Barakawi variety, the most predominant one was selected. A Completly Randomized Design with 6 replicates (one tree = replicate) was used.

Experimental sites: The first experimental site is Elgaba scheme. Two farms in the middle of the scheme were selected. Their history of infestation dated about 6 years earlier and the estimated loss in date yield was more than 70% and 80% for Barakawi and Gondeilla varieties, respectively. Palm age and hights were between 15 - 20 years, 10- 15 meters, respectively. Flood method of irrigation from the Nile is conducted monthly via the scheme's main canal. Supplementary irrigation is given using diesel pump from underground water. Urea was usually added in summer for intercropping fodder crops (maize, durra and legumes). No chemical control has been conducted in the area before.

As a result of the intensive chemical control program in Elgaba scheme in April – June 2004, the experimental site, was moved to El Golid area. The locations selected were two farms, the first (location 1) was a farm by the bank of the Nile and the second (location 2) is three kilometers from the Nile, both were highly infested. The age of trees was between 10 and 15 years with hights ranging between 8 and 10 meters. Intercropping with fodder crops was dominant. Urea and cattle manure were applied to

57 fodder crops. Flood method of irrigation from the Nile is conducted during the flood season.Supplementary irrigation is given using diesel pump from underground water.

The estimated loss in yield was more than 60% and 70% for Barakawi variety in location (1) and (2) respectively. Chemical control was conducted in the two locations using contact insecticides during the extensive control program in this area in 1991.

Cultural practices followed before the experiments: The following cultural practices (plate 3) were usually carried out: a. Pruning, removal of dead leaves and the lowest row of the highly infested leaves. b. Raising earth around the palm to facilitate irrigation (every tree is irrigated individually) c. Pre-watering (24 hours) before application (of the insecticides) using diesel pumps from underground water.

3.1.1 Soil application method

3.1. 1.1 Season 2003/2004. An experiment was conducted in Elgaba scheme to test the efficacy of thiamethoxam as Actara 25 WG on the date palm green pit scale insect {this insecticide belongs to the neonicotinoid group. Chemically it is 3-(2-chloro-thiazol-5- ylmethyl)-5-methyl-(1, 3, and 5)-oxadiazinan-4-ylidene-N-nitroamine}.Four doses of Actara 25 WG; 9, 12, 15 and 18 g /tree (2.25, 3, 3.75, 4.5 g a.i. / tree) were tested and compared to standard insecticide Confidor 200Sl at 35ml(7 g a.i) /tree (Ahmed et.al 2002) and untreated control (using water only). The specific dose was diluted with eight liter of water in a container and drenched around the date palm tree (plate 3) and then irrigated as mentioned above.The Completely Randomized Design with six replicates (one palm = one replicate) was used. A residue analysis was carried out on dates, soil and intercropped plants twice at harvest.

Cultural practices before experiments Cultural practices before experiments (pruning) (irrigation basin)

Cultural practices before experiments Preparing insecticides for soil application (pre watering)

Soil application with diluted insecticide preparing insecticides for soil application (Actara 25 WG) Plate 3. Cultural Practices before bioassay and soil application technique

3.1. 1.2 Season 2004/2005. Two imidacloprid formulations (Rinfidor 20% SL and Comodor 20% SL) were used beside the insecticides tested in the previous season (2003/2004). Therefore, the following treatments were used: 1. Thiamethoxam as Actara 25 WG at 4.5g.a.i / tree (18g product) 2. Thiamethoxam as Actara 25 WG at 3.75g.a.i / tree (15g product) 3. Thiamethoxam as Actara 25 WG at 3g.a.i / tree (12g product) 4. Imidacloprid as Rinfidor 20%SL) at 7g.a.i / tree (35ml product) 5. Imidacloprid as Rinfidor 20%SL at 5g.a.i / tree (25ml product) 6. Imidacloprid as Rinfidor 20%SL at 4g.a.i / tree (20ml product) 7. Imidacloprid as Comodor 20%SL at 7g.a.i / tree (35ml product) 8. Imidacloprid as Comodor 20%SL at 5g.a.i / tree (25ml product) 9. Imidacloprid as Comodor 20%SL at 4g.a.i / tree (20ml product) 10. Imidacloprid as Confidor 200SL at 7 g.a.i/ tree (35ml product) (standard) 11. Untreated control, (by sprayed with water only).

The common names, trade names, toxicity data and supplier of the tested insecticides are shown in Appendix (2). A residue analysis was carried out on dates, soil and intercropped plants twice at harvest.

3.1.1.3 Insects count Samples of eight leaflets (two leaflets from each of the four main directions) were inspected at biweekly intervals and examined under binocular microscope. The number of living and dead adult females and immature stages were recorded per three cm² of each leaflet (tip, top and bottom). An average per cm² was obtained and the following parameters were calculated: a) Percentage mortality of adult females. b) Percentage mortality of immature stages. Pre-spray count was undertaken before insecticide application.

3.1.1.4 Yield and yield components At harvest, triplicate samples of 50 date fruits were taken at random from each replicate, collected samples were used to assess the percentage fruit maturity (ripening).Sub-samples of ten date fruits were taken to the lab to determine the following parameters: a) Mean fruit weight (g) b) Mean fruit length(L) (cm): c) Mean fruit diameter (D) (cm): d) The L/D ratio e) Percent seed/fruit weight. Yield in kilogram per palm was determined at harvest. Samples of date fruits, soil and grasses were taken to ARC laboratory at Wad Medani for residue analysis.

3.1.2 Trunk Injection Technique Holes of 15 cm deep were bored into the trunk and an open end snout metallic tube was inserted. The tube; 25 cm in length and 1.5 cm in diameter was inserted into the hole at an angle of 45° about one meter above the ground. The tube can hold at least 25 ml of the diluted insecticide (Al-Jbooryi et.al, 2001). A developed calibrated “drench mastic” injection gun (used by Fernandez and Gllego, 1997 and Filer, 1973) was not available, so a 25 ml measuring cylinder was used for this purpose. When the injection was over, the tube was closed with tight- fitting flap. Apart from gloves the user also wore a mask for face and eye safety (plate 4).

The following insecticides were used at the following doses. The injection volume was made upto 25ml using tap-water

Elgaba scheme, season 2003/2004 1) Thiamethoxam as Actara 25 WG at 10 g / tree (2.5 g a.i) 2) Thiamethoxam as Actara 25 WG at 8 g / tree (2.0 g a.i.) 3) Thiamethoxam as Actara 25 WG at 6 g / tree (1.25 g a.i) 61

4) Imidacloprid as Confidor 200SL at 20 ml / tree (4g a.i.) 5) Imidacloprid as Confidor 200SL at 15 ml / tree (3g a.i.) 6) Imidacloprid Confidor 200SL at 10 ml / tree (2g a.i.) 7) Untreated control (by injecting with water only)

El Golid area, season 2004/2005 1) Thiamethoxam as Actara 25 WG at 2.5 g a.i / tree (10 g product) 2) Thiamethoxam as Actara 25 WG at 2.0 g a.i. / tree (8 g product) 3) Thiamethoxam as Actara 25 WG at 1.25 g a.i. / tree (6 g product) 4) Imidacloprid Confidor 200SL at 4g a.i / tree (20 ml product) 5) Imidacloprid Confidor 200SL at 3g a.i. / tree (15 ml product) 6) Imidacloprid Confidor 200SL at 2g a.i. / tree (10 ml product) 7) Imidacloprid Rinfidor 20%SL at 7g.a. i. / tree (35ml product) 8) Imidacloprid Rinfidor 20%SL at 5g.a.i. / tree (25ml product) 9) Imidacloprid Rinfidor 20%SL at 4g.a.i. / tree (20ml product) 10) Imidacloprid Comodor 20%SL at 7g.a. i. / tree (35ml product) 11) Imidacloprid Comodor 20%SL at 5g.a.i / tree (25ml product) 12) Imidacloprid Comodor 20%SL at 4g.a.i / tree (20ml product) 13) Untreated control (by injecting with water only)

Insects count, yield and yield components and samples for residual analysis as described above.

Trunk injection(local equipments) Trunk injection(boring a hole into trunk)

Injecting the undiluted insecticide

Trunk injection (inserting the tube into the trunk) Injecting the undiluted insecticide into the trunk

Plate 4. Trunk injection technique

3.1.3 Residue analysis of the tested compounds 3.1.3.1 Residues of thiamethoxam as Actara 25 % WG in Date palms.

1. Treatment and sampling: The insecticide was applied by two methods (soil application and trunk injection) at dosage rate of 4.5g a.i./tree (18g product) and 2.5g a.i (10g product) for soil application and trunk injection, respectively. The treatments were done on 15/6/2003.

Treated and control samples of date palm fruits, soil, and intercropped plants were taken in three replicates from the two types of applications. Samples were collected early season, 25/8/2003 (unripe fruit stage) and at harvest 1/10/2003. Samples collected were brought to the laboratory; the samples were reduced by quartering and kept at –20 ºc for residue analysis.

2- Extraction and Clean- up The method of residue analysis employed was provided by Syngenta Analytical Department (REM 179.01). Sub-samples (10 g) each were taken in triplicate from each of the treated and replicates they include grass and date palm fruits. The material was extracted by homogenizing with 50 ml of a mixture of water / methanol (1:4 v/v) using a high- speed blender for three minutes. The homogenized material was filtered through a Buchner funnel into an Erlenmeyer flask using Celite filter aid. The filtrate was transferred into a 100 ml volumetric flask and brought to volume with the same solvent mixture. An aliquot of 5 ml of the filtered extract was diluted with the same volume of water and cleaned-up by solid phase extraction using disposable solid- phase columns (Bond Elut C-18). Elution was done using water / tetrahydrofuran (1:4 v/v). The eluates were then concentrated to dryness and the residues were taken into the minimum amount of acetone (0.5 ml) and kept for analysis. The extraction of soil samples was done by shaking 50 g soil sample with 200 ml water/ methanol mixture (1:4 v/ v) for two hours using a horizontal shaker. 64

3- Analysis

Analysis was carried out by thin-layer chromatography (T L C) using ready- made silica gel GF 254 coated plates with a thickness of 0.25mm (Merck). After spotting of thiamethoxam standard and samples, the plates were developed in a system of isopropanol / toluene (1:1), and visualized under a short wave ultra violet lamp (254 nm). RF values were determined.

3.1.3.2 Residues of imidacloprid used as Confidor 200 SL, Renfidor 20% SL and Comodor 20% SL. 1. Treatment and sampling: The insecticides were applied by two methods, soil application and trunk injection; the treatments were done on 10/6/2004 at dosage rates as mentioned in (3.1.1.2) and (3.1.2). Samples contain date palm fruits, intercropped plants and soil were collected from sites treated with high doses; 35ml product/tree (7g. a.i.) and 20ml product/tree (4g a.i.) for soil application and trunk injection, respectively. Samples were collected early season, 20/8/2004 (unripe fruit stage) and at harvest 1/10/2004.

2. Extraction and clean up For analysis, sub-sampls of 50g date fruits were taken randomly from treated and untreated trees and intercropped plants, and then mixed with 300ml of methanol/water mixture (3:1) and allowed to soak for 30 minutes. Then the sample was homogenized and filtered using 10g celite as filter aid. The filterae was transferred into a graduated cylinder, filled up with methanol to total of 250ml and homogenized by agitation. An aliquot (100ml) was removed. Transferred into 1000ml round-bottomed flask and concentrated to about 20ml using rotary evapulator.

Clean up was carried out using 10g Amberlite XAD 4 resin packed into a chromatography column having an inner diameter of 10mm. the column was

65 prewetted with methanol and water. All aqueous elutes were discarded. The residues were eluted with 100ml methanol. This elute was collected and concentrated to dryness and the residues were taken into 0.5ml acetone and kept for analysis.

3. Analysis Analysis was carried out by thin-layer chromatography (TLC); on ready made silica gel GF254 coated plates. After spotting of the samples and standard of imidacloprid, the plates were developed in a system of isopropanol/toluene (1:1) and visualized under short wave ultra violet lamp. (254nm).

3.2 Economic feasibility of controlling the green pit scale insect with imidacloprid as Confidor 200SL.

A study was conducted to evaluate the economic feasibility of control of the green scale insect in the Northern State using soil application of Confidor 200SL and improved cultural practices versus the traditional farmers’ practices.

Partial budget analysis was applied to test the profitability of control measures of the green scale insect using the recommended package that includes: 1- Raising earth around the date palm tree to facilitate irrigation, and 2- Removal of the dead and the highly infested leaves. 3- Soil application of Confidor 200 SL 35 ml (7g a.i.) / date palm tree.

Costs and benefits of the variable items were obtained from a survey conducted in 2007 including farmers who used the package and others who did not use the package. Calculations were done for irrigation (including raising earth),cleaning (removal of dead leaves ) and harvesting cost per one tree according to the survey results. Price of Confidor 200SL was 175 SDG / liter, which was sufficient for about 28 date palm trees at the rate of 35 ml / tree (results of soil application). Average dates yield ( kg / tree) is obtained from the surveyed farmers.Average dates price was 70 SDG per 100

66 kg (Field price). The analysis was conducted by the Agricultural Economics and Policy Studies Section of Dongola Research Station , ARC .

3.3 Varietal susceptibility About four locations in the infested area were selected (Elgaba scheme ,El Golid area ,Elbaja area and Old Dongola).The four date palm varieties; Barakawi, Gondiella, Waddlagi and Jaw, in the areas were selected and visited monthly for five monthes, during the period from Augast to December 2006. Leaves samples were taken as mentioned earlier .All developmental stages (alive or dead) of the green pit scale insect were counted per leave.

3.4 Natural enemies’ assoicated with the green pit scale insect in the Northern State, Sudan. Four locations in the infested area were selected (Elgaba scheme, El Golid area, Elbaja area and Old Dongola). The four date palm varieties; Barakawi, Gondiella, Waddlagi and Jaw, were observed for the natural enemies especially the predators. Ten trees were chosen at random from each variety grown in farms with intercropping or without intercropping.Samples were taken monthly for five months, during the period from August to December 2006. All natural enemies (adults or larvae) were counted per leaf and all developmental stages (alive or dead) of the green pit scale insect were also counted.

4: RESULTS

4.1 Soil application method 4.1.1 Insects count 4.1.1.1 Season 2003/ 2004 Experiments using the soil application technique were conducted in Elgaba scheme for the first season using Actara 25 WG (thiamethoxam) at four doses (9, 12, 15 and 18 g product / tree) and Confidor 200SL (imidacloprid) at the recommended dose of 35ml / tree as standard.

Results of biweekly counts (Table 2) indicated that all insecticide doses increased the mortality of adult females and immature stages of the insect. The results were significantly different from the control (untreated) throughout the test period (three weeks after application). The total number of dead insects (adult females and immature stages) / cm² of leaflet after four weeks were 8.5, 7.4, 4.6, 3.5, 1.9 and 1.0 for Actara (18 g), Confidor (35ml), Actara (15g), Actara (12g), Actara (9g) and untreated control, respectively. The total death for the same doses by the end of the count after 12 weeks was, 7.9, 7.3, 3.9, 3.0, 1.9 and 1.2 respectively. The percentage mortality of the adult females and immature stages (Table 3 and Appendix: 7-1) significantly increased in trees treated with insecticides compared with the untreated control. More than 90% of adult female's mortality was observed in the higher doses of Actara (18 and 15 g) and Confidor (35ml) weeks from application. While similar percentage mortality of immature stages was observed for the same doses only two weeks after application. A high percentage of adult female mortality was observed after twelve weeks (last count) for higher doses of Actara (18g) and Confidor (35ml).

Table (2) Mean biweekly total mortality of adult females and immature stages of green pit scale insect from trees treated with different insecticides (using soil application method) at Elgaba scheme, season 2003/2004. Insecticide Dosage rate /palm No. of dead scales at weeks after application 0 2 4 6 8 12 Actara 25WG 18g (4.5g a.i) 1.0(1.2) 8 (2.9)A 8.5 (3)A 10.9 (3.4)A 8.1 (2.9)A 7.9 (2.9)A Actara 25WG 15g (3.75g a.i) 0.7 (1.1) 3 (1.9)B 4.6 (2.3)B 5.6 (2.5)BC 5.8 (2.5)B 3.9 (2.0)B Actara 25WG 12g (3g a.i) 0.9 (1.2) 1.7 (1.5)BC 3.5 (2.0)B 4.3 (2.2)C 3.6 (2.0)C 3 (1.8)BC Actara 25WG 9g (2.25g a.i) 0.8 (1.1) 1.1 (1.2)C 1.9 (1.6)C 3.9 (2.1)C 2.5 (1.7)D 1.9 (1.6) CD Confidor200SL 35ml (7g a.i) 1.1 (1.2) 6.8 (2.7)A 7.4 (3.8)A 8.1 (2.9)AB 8.5 (3.0)A 7.3 (2.8)A Untreated control water only 0.5 (1.0) 0.94 (1.2)C 1.0 (1.1)D 1.2 (1.3)D 1.2 (1.3)E 1.2 (1.3)D

SE± 0.1 0.14 0.1 0.22 0.1 0.14 C.V% 17.4 15.2 6.7 18.6 8.4 13.7 - Data in brackets were √x+0.5. - Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test}.

Table (3) Mean biweekly percentage mortality of adult females and immature stages of green pit scale insect from trees treated with different insecticides (using soil application method) at Elgaba Scheme, season 2003/2004. A : Adult females % Mortality at weeks after application Insecticide Dosage rate/palm 0 2 4 6 8 12 Actara 25WG 18g (4.5g a.i) 8.5 (17.0) 99.9 (88.3)A 98.6(83.2)AB 99.9 (89.0)A 97 (80.01)A 100 (97.5)A Actara 25WG 15g (3.75g a.i) 16.2 (23.8) 99.7 (86.9)A 90.0 (71.6)BC 88.0 (69.8)B 89.5 (71.0)AB 99.9 (88.5)A Actara 25WG 12g (3g a.i) 6.2 (15.45) 66.5(54.6)ABC 81.6 (65.33)C 80 (63.7)BC 80.2 (63.6)B 79.5 (67.6)B Actara 25WG 9g (2.25g a.i) 14.6 (22.4) 55.1(47.9)BC 78.5 (62.4)C 70.5 (57.0)C 33.8 (35.6)C 79.9 (63.4)A Confidor200SL 35ml (7g a.i) 9.6 (18.11) 86.2 (68.2)AB 99.9 (88.9)A 100 (99.1)A 96.3 (78.9)AB 100 (96.7)B Untreated control water only 14.7 (22.8) 14.0 (22.03)C 20.5 (26.93)D 22.2 (28.1)D 24.8 (29.9)C 20.2 (26.7)C

SE± 4.9 9.5 3.19 3.23 2.24 4.67 C.V% 49.5 31 9.63 9.52 14.2 12.7 B: Immature stages Actara25WG 18g (4.5g a.i) 17.5 (24.7) 99.7 (87)AB 100 (97.2)A 100 (97.2)A 100 (93)AB 100 (96.3)A Actara 25WG 15g (3.75g a.i) 11.2 (19.6) 94.9 (76.9)BC 96.2 (78.8)B 98.1 (82.2)AB 99.4 (85.9)B 99.8 (88.2)B Actara 25WG 12g (3g a.i) 12.8(20.9) 82.9 (65.7)CD 91.7 (73.3)BC 63.5 (75.2)BC 90.9 (72.4)C 96.2 (78.8)C Actara 25WG 9g (2.25g a.i) 7.2 (15.5) 80.1 (63.6)D 84.2 (66.6)C 75.9 (60.4)C 76.7 (61.1)D 89.7 (71.3)C Confidor200SL 35ml (7g a.i) 9.2 (18.1) 100 (93.3)A 100 (99.4)A 100 (91.6)AB 100 (96.2)A 100 (94.8)AB Untreated control water only 15.5 (23.2) 17.6 (24.9)E 17.1 (24.4)D 24.5 (29.7)D 22.7 (28.5)E 21.7 (27.8)D

SE± 2.87 3.49 2.24 5.32 2.69 2.13 C.V% 30.3 10.2 6.1 14.6 7.4 5.6 - Data in brackets were arcsine transformed. - Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

4.1.1.2 Season 2004 / 2005 Based on results obtained from the first season in Elgaba scheme, three concentrations of Actara (thiamethoxam); (18g, 15g and 12g product/ tree), Confidor 200SL (imidacloprid) (35ml/ tree as standard), as well as two imidacloprid Rinfidor 20%SL and Comodor 20%SL were tested in season 2004 /2005. They were each tested at dosages of 20, 25, and 35ml/ tree. Two locations were selected, (one at the bank of the River Nile and the other three kilometers from the Nile).

Results in (Table 4) indicate that all doses significantly increased total death of adult females and immature stages. The higher dose gave excellent insect suppression. High mortality percentage was recorded at four weeks after application for adult females (Table 5 and Appendix: 7-2) and after only two weeks for immature stages (Table 6 and Appendix: 7-3).

4.1.2 Yield and yield components 4.1.2.1 Season 2003/2004 Data Presented in Table 7 showed the effect of different doses of Actara and Confidor on the average yield per tree. The percentage of ripe fruits (% maturity) and fruit weight (g), fruit length, L (cm), fruit diameter, D (cm), L/D ratio and % seeds / fruit weight ( as physical characteristics) were reported. Date palms treated with higher doses of Actara (18g) and Confidor (35ml) showed a high percentage of ripe fruits with no losses. They also showed the highest fruit weight (g) and the lowest percentage of seed/ fruit weight resulting in a higher yield compared to the untreated control (plate 5a, and d).

Table (4) Mean biweekly total mortality of adult females and immature stages of green pit scale insect from trees treated with different insecticides (using soil application method) at El Golid, season 2004/2005. A: Location 1 (at the bank of Nile) % Mortality at weeks after application Insecticides Dosage 0 2 4 6 8 12 rate/palm Actara25WG 18g (4.5g a.i) 0.4 (0.9) 2.9 (1.8)A 2.0 (1.6)BC 1.6 (1.5)ABCD 1.7 (1.5)ABC 1.7 (1.5)AB Actara 25WG 15g (3.75g a.i) 0.5 (1.0) 1.6 (1.6) BC 1.9 (1.5)BC 1.5 (1.4)ABCD 1.6 (1.4)ABC 1.7 (1.5)AB Actara 25WG 12g (3 g a.i) 0.5 (1.0) 1.2 (1.3)BCD 1.8 (1.5)BC 1.4(1.4)ABCD 1.2 (1.3)ABC 0.6 (1.1)B Rinfidor 20%SL 35ml (7g ai) 0.5 (1.0) 0.96(1.4)BCD 3.9 (2.1)A 2.4 (1.7)AB 2.5 (1.7)A 3.0 (1.9)A Rinfidor 20%SL 25mi (5g ai) 0.4 (0.9) 0.9 (1.2)BCD 2.9 (1.8)AB 1.0 (1.2)BCD 1.5 (1.4)ABC 1.7 (1.5)AB Rinfidor 20%SL 20ml (4g ai) 0.3 (0.8) 0.6 (1.5)CD 0.4 (1.2) C 0.9 (1.2)BCD 0.8 (1.2)BC 0.5 (1.4)B Comodor 20%SL 35ml (7g ai) 0.5 (1.0) 2.2 (1.7)AB 2.1 (1.6)BC 2.5 (1.7)A 1.8 (1.5)AB 1.1 (1.7)AB Comodor 20%SL 25mi (5g ai) 0.2 (0.8) 1.3 (1.3)BCD 1.2 (1.3)CD 1.8 (1.5)ABC 1.4 (1.1)ABC 1.7 (1.5)AB Comodor 20%SL 20ml (4g ai) 0.3 (0.9) 1.3 (1.3)BCD 1.1 (1.3)CD 1.3 (1.1.3)ABCD 1.4 (1.4)ABC 1.2 (1.3)AB Confidor200SL 35ml (7g ai) 1.0(1.2) 1.2 (1.3)AB 4.3 (2.2)A 1.8 (1.5)ABC 2.1 (1.6)A 1.3 (1.3)AB Untreated control water only 0.6 (1.1) 0.5 (0.9)D 0.4 (1.0)D 0.5 (1.0)D 0.6 (1.0)C 0.3 (0.9)B

SE± 0.08 0.13 0.14 0.14 0.13 0.53 C.V% 16.6 19 18 19.5 18.5 29 B: Location 2 (three km from the Nile Actara 25WG 18g (4.5g a.i) 0.7 (1.1) 4.2 (2.2)A 5.3 (2.4)A 3.9 (2.1)A 3.9 (2.1)A 5..9 (2.5)A Rinfidor 20%SL 35ml (7g ai) 0.8 (1.1) 2.3 (1.7)A 4.4 (2.2)AB 3.1 (1.9)A 3.6 (2.0)A 3.6 (2.0)B Comodor 20%SL 35ml (7g ai) 0.7 (1.1) 4.8 (2.3)A 3.3 (1.9)B 4.3 (2.1)A 3.6 (2.0)A 3.6 (2.0)B Confidor 200SL 35ml (7g ai) 0.5 (1.06) 3.5 (2.0)A 3.7 (2.0)AB 4.0 (2.1)A 3.9 (2.1)A 4.0 (2.1)B Untreated control water only 0.7 (1.0) 1.0 (1.2)B 0.7 (1.1)C 0.9 (1.2)B 0.9 (1.2)B 0.8 (1.2)C

SE± 0.06 0.16 0.11 0.11 0.11 0.07 C.V% 9.2 15.2 9.9 10.3 9.8 6.2 - Data in brackets were arcsine transformed. - Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

Table (5) Mean biweekly percentage mortality of adult females of green pit scale insect from trees treated with different insecticides (using soil application method) at El Golid, 2004/2005. A: Location 1 (at the bank of Nile) %Mortality at weeks after application Insecticides Dosage 0 2 4 6 8 12 rate/palm Actara 25WG 18g (4.5g a.i) 15.1 (22.9) 72 (58)AB 99.7 (875)A 100 (98.8)A 100 (99.3)A 100 (98.6)AB Actara 25WG 15g (3.75g a.i) 16.0 (23.6) 65.5 (54.5)AB 83.3 (65.1)C 100 (98.2)A 100 (96.2)A 100 (90.4)BCD Actara 25WG 12g (3 g a.i) 21.6 (27.7) 59.8 (50.7)ABC 77.1 (61.4)C 100 (91.5)A 99.7 (87.2)B 99.9 (88.5)CD Rinfidor 20%SL 35ml (7g ai) 23.0 (28.7) 89.3 (71.1)A 99.3 (85.2)A 100 (94.6.3)A 100 (95.3)AB 100 (96.7 )ABC Rinfidor 20%SL 25mi (5g ai) 19.7 (26.4) 73.8 (59.2)AB 81.6 (64.7)C 99.3 (85.3)AB 100 (96.1)AB 100 (91.9)ABCD Rinfidor 20%SL 20ml (4g ai) 25.6 (30.4) 58.5 (49.9)ABC 77.6 (61.8)C 91.8 (73.4)B 100 (93.5)AB 99.7 (87.1)D Comodor 20%SL 35ml (7g ai) 20.5 (26.9) 72.2 (58.2)AB 99.6 (86.6)A 100 (98.7)A 100 (94.9)AB 100 (99.1)A Comodor 20%SL 25mi (5g ai) 10.6 (19.0) 58.1 (49.7)ABC 89.9 (71.5)BC 100 (94.8)A 100 (91.1)AB 99.2 (85.0)D Comodor 20%SL 20ml (4g ai) 7.1 (15.5) 52.8 (49.0)BC 78.1 (62.1)C 100 (92.8)A 99.9 (89.5)AB 99.2 (85.1)D Confidor200SL 35ml (7g ai) 11.1 (19.8) 79.0 (62.7)AB 100 (99.4)A 100 (98.8)A 100 (99.2)A 100 (98.6)AB Untreated control water only 21.7 (27.8) 20.4 (26.8)C 23.1 (28.7)D 18.9 (25.8)C 3.4 (107)C 7.2 (15.6)E

SE± 3.15 6.97 4.41 3.88 3.15 2.52 C.V% 25.8 26.1 12.6 9.0 7.3 5.9 B: Location 2 (three km from the Nile) Actara 25WG 18g (4.5g a.i) 20 (26.5) 89.7 (71.3)A 96.9 (76.8)B 95.6 (77.9)B 100 (92.5)A 99.3 (84.7)A Rinfidor 20%SL 35ml (7g ai) 16.6 (24.1) 91.5 (73)A 100 (90.9)AB 100 (99.5)A 100 (99.5)A 100 (92.5)A Comodor 20%SL 35ml (7g ai) 18.3 (25.3) 90.8 (72.3)A 100 (99.7)A 100 (99.7)A 100 (99.7)A 100 (99.6)A Confidor 200SL 35ml (7g ai) 25.6 (3.4) 96.5 (79.2)A 100 (99.7)A 100 (99.6)A 100 (99.7)A 100 (99.7)A Untreated control water only 18.6 (25.6) 16.5 (24.B 21.9 (27.6)C 22.4 (28.3)C 24.3 (29.5)B 24.4 (29.6)B

SE± 1.75 3.57 4.27 1.4 3.31 5.19 C.V% 11.5 9.7 9.4 3.0 6.8 11.1 -Data in brackets were arcsine transformed. -Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

Table (6) Mean biweekly percentage mortality of immature stages of green pit scale insect from trees treated with different insecticides (using soil application method) at El Golid, 2004/2005 (Location 1 and 2). A: Location 1 (at the bank of Nile) %Mortality at weeks after application Insecticides Dosage rate/palm 0 2 4 6 8 12 Actara 25WG 18g (4.5g a.i) 13.2 (21.3) 100 (99.5)A 100 (94.2)A 100 (98.7)A 100 (99)A 100 (98.6)AB Actara 25WG 15g (3.75g a.i) 12.1 (20.4) 100 (99.5)A 100 (93.7)A 100 (98.2)A 100 (96)AB 100 (90)BC Actara 25WG 12g (3 g a.i) 11.9 (20.2) 89.3 (71)B 100 (94.1)A 100 (91)AB 99.7 (87)B 99.9 (88.6)C Rinfidor 20%SL 35ml (7g ai) 9.9 (18.3) 100 (99.5)A 100 (98)A 100 (99.9)A 100 (95)AB 100 (96)AB Rinfidor 20%SL 25mi (5g ai) 11.7 (20) 100 (99.5)A 100 (96.1)A 100 (96 )AB 100 (95)AB 100 (91.9)ABC Rinfidor 20%SL 20ml (4g ai) 9.6 (18) 72.7 (58.5)D 100 (98.1)A 89 (70)C 100 (93)AB 99.1 (84)C Comodor 20%SL 35ml (7g ai) 14 (21.9 100 (99.5)A 100 (95)A 100 (98)A 100 (94)AB 100 (99)A Comodor 20%SL 25mi (5g ai) 9.1 (17.5) 100 (99.5)A 100 (95)A 100 (94)AB 100 (91)AB 99.2 (85)C Comodor 20%SL 20ml (4g ai) 10.5 (18.9) 80 (68.5)C 100 (97)A 100 (92)AB 99.9 (89)AB 99.3 (84)C Confidor200SL 35ml (7g ai) 18.3 (25.3) 100 (99.5)A 100 (97)A 100 (98)A 100 (97)AB 100 (98)AB Untreated control water only 17.8 (24.9) 25.7 (30.5)E 23.5 (29.2)B 18.9 (25.8)D 3.4 (10.7)C 15 (7.2)D

SE± 4.36 1.41 1.53 3.55 3.20 2.41 C.V% 42.3 3.4 3.7 8.2 7.4 5.7 B: Location 2 (three km from theNile) Actara 25WG 18g (4.5g a.i) 22.9 (28.7) 93.1 (74.8)A 99.9 (89.6)A 84.2 (66.6)AB 100 (99.5)A 100 (99.2)A Rinfidor 20%SL 35ml (7g ai) 22.9 (28.6) 99 (84.3)A 100 (99.4)A 100 (99.4)A 100 (99.6)A 100 (99.5)A Comodor 20%SL 35ml (7g ai) 24.9 (29.9) 99.9 (89)A 100 (99.5)A 100 (99.4)A 100 (99.4)A 100 (99.5)A Confidor 200SL 35ml (7g ai) 26.6 (31.1) 99.8 (87.7)A 100 (99.6)A 100 (99.5)A 100 (99.5)A 100 (99.6)A Untreated control water only 24.9 (29.9) 24.7 (29.8)B 27.6 (31.7)B 22.4 (28.3)B 23.1 (28.7)B 25.6 (30.4)B

SE± 1.4 6.28 2.55 14.54 0.37 0.88 C.V% 8.2 14.9 5.3 32 0.75 1.8 -Data in brackets were arcsine transformed. -Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Te

Table (7) Yield and yield components of date fruits from trees treated with different insecticides (using soil application method) at Elgaba scheme, Season 2003/2004. Insecticide Dosage rate/palm %ripe fruit Fruit weight Fruit length Fruit diameter L/D ratio %seed/ Yield (g) (cm) L (cm) D Fruit wt. kg/palm Actara25WG 18g (4.5g a.i) 100A 8.5AB 4.9A 1.6 3.0 9.8B 90.0A Actara 25WG 15g (3.75g a.i) 90B 7.4BC 4.6A 1.6 2.9 10.5B 59.5B Actara 25WG 12g (3g a.i) 80C 7.2C 4.5A 1.6 2.8 13.5A 57.7B Actara 25WG 9g (2.25g a.i) 72.5C 6.7CD 4.4A 1.5 2.8 12.8A 47.0B Confidor200SL 35ml (7g a.i) 100A 8.2A 4.7A 1.7 2.9 10.0B 108.3A Untreated control water only 48.6D 6D 3.8B 1.6 2.5 14.5A 22.5C

SE± 2.35 0.21 0.12 0.07 0.13 0.52 5.6 C.V% 5.8 5.7 5.3 9 9.1 8.9 17.5 Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

4.1.2.2 Season 2004/2005 All insecticides with higher doses allow full maturity of fruits. Physical characteristics of fruits (fruit weight, fruit length (L), fruit diameter (D), L/D ratio and % seed/fruit weight) confirm the effectiveness of the high insecticide doses at the two locations (Table 8). Physical fruit characteristics and yields in the two locations confirmed results obtained in the first season where the highest yields were obtained in the higher doses treatments; Actara (18g), Rinfidor (35ml), Comodor (35ml) and Confidor (35ml).

4.2 Trunk injection method. 4.2.1 Insects count The mean biweekly total death (adult females and immature stages/ cm² of leaflet) for the first season 2003 / 2004 (Table 9) was significantly increased for all insecticides used compared with untreated control throughout the experimental period. The higher doses of insecticides resulted in the higher number of dead insects. Similar results were obtained in the second season (2004 /2005) in El Golid (Table 11) when Actara and Confidor as well as Rinfidor 20%SL and Comodor 20%SL were used. The higher doses were superior to the lower doses and the untreated control in number of total dead insects even 12 weeks after application (the last count).

Results of percentage mortality of adult females and immature stages in the first season in 2003 / 2004 season (Table 10 and Appendix: 7-4) showed the high efficacy of insecticides as reflected by the hundred percent mortality of adult female and immature stages during the second week after injection throughout the rest of counts. Similar results were obtained in the second season (2004 / 2005) as show in Table 12, Table 13 and Appendix: 7-5 The new imidacloprid commercial compounds, Rinfidor and Comodor, showed an effective performance similar to Confidor.

Table (8) .Yield and yield components of date fruits from trees treated with different insecticides, (using soil application method) at El Golid, season 2004/2005. A: Location 1 (at the bank of Nile) Insecticide Dosage /palm % Ripe fruit Fruit wt. (g) Fruit length, L Fruit diameter, D L/D ratio % seed/ Yield (cm) (cm) fruit wt. (kg/palm) Actara 25WG 18g (4.5g a.i) 100 A 5.7ABCD 4.5A 1.6 3.0ABC 10.8C 82.5A Actara 25WG 15g (3.75g a.i) 92.5AB 5.0ABCDE 3.5B 1.6 2.3D 14.8BC 59.5CD Actara 25WG 12g (3 g a.i) 75C 4.0 EF 3.7B 1.6 2.3D 17B 50D Rinfidor 20%SL 35ml (7g ai) 97.5A 5.7 ABC 4.5A 1.5 3.03AB 12.8BC 78.5AB Rinfidor 20%SL 25mi (5g ai) 97.5A 5.1 ABCDE 3.8B 1.6 2.5BCD 15BC 59.3CD Rinfidor 20%SL 20ml (4g ai) 85BC 4.6 BCDEF 3.5B 1.5 2.4D 15.5BC 55.8CD Comodor 20%SL 35ml (7g ai) 100A 6.3A 4.6A 1.5 3.1A 11.5BC 72.5B Comodor 20%SL 25mi (5g ai) 93AB 4.2CDEF 3.7B 1.4 2.7ABC 13.5BC 61.5C Comodor 20%SL 20ml (4g ai) 75C 4.1DEF 3.6B 1.5 2.4CD 12.5BC 54.3CD Confidor200SL 35ml (7g ai) 100A 5.9AB 4.6A 1.5 3.0ABC 12.5BC 83.5A Untreated control water only 45D 3.1F 2.8C 1.3 2.1D 22.8A 12.3E

SE± 3.42 0.45 0.19 0.07 0.18 1.68 2.87 C.V% 7.8 18.4 9.7 9.4 13.6 23.3 9.4 B: Location 2 (three km from the Nile) Actara 25WG 18g (4.5g a.i) 100A 8.6A 4.6A 1.6 4.5A 9.0B 103.7A Rinfidor 20%SL 35ml (7g ai) 100A 6.4BC 4.6A 1.7 4.0AB 10.0B 96.7A Comodor 20%SL 35ml (7g ai) 100A 6.4BC 4.4A 1.6 2.8BC 11.0B 96.3A Confidor 200SL 35ml (7g ai) 100A 8.4AB 4.4A 1.7 2.6C 9.0B 103.3A Untreated control water only 53.3B 5.1C 3.3B 1.5 2.3C 19.0A 30.0B

SE± 1.49 0.55 0.16 0.06 0.34 0.59 4.13 C.V% 2.9 13.6 6.4 6.8 18.2 8.83 8.3 Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Tes

4.2.2 Yield and yield components Results in Table 14 indicate that, all doses of different insecticides significantly affected yield and physical characters of date’s fruits compared to the untreated control. The higher doses of Actara (10g) and Confidor (20ml) resulted in higher fruit weight, fruit length and a lower seed/ fruit weight percentage indicating a higher yield. An increase in yield (75%) was observed relative to the untreated control.

Results of the second season 2004 / 2005 at El Golid (Table 15) confirmed the above mentioned results. All treatments were superior to the untreated control in yield and yield components except the fruit diameter and percentage seed / fruit weight. The higher yields (kg / tree) were observed in the higher doses of different insecticides.

4.3 Results of residue analysis Rinfidor 20% SL, Comodor 20% SL and Confidor 200 SL are formulation of imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazoldin-2-ylideneamine)]. Results of residue analysis indicated that, the residues of imidacloprid and its metabolites were below the detection limit (0.09 µg) in all samples analyzed. The Rf of imidacloprid was 0.53. This result indicated that the usage of Rinfidor 20 % SL, Comodor 20 % SL and Confidor 200 SL at the rate of 35 ml/ tree on the date palms are safe for human consumption.

According to the TLC results the Rf value for thiamethoxam standard was 0.56. The minimum detectable amount of Thiamethoxam standard was 0.1 µ g . The recovery of the method was 85 % No residues of Thiamethoxam and metabolites were detected in all samples examined.

Table (9) Mean biweekly total mortality of green pit scale insect from trees treated with different insecticides (using trunk injection method) at Elgaba scheme season 2003/2004. Insecticide Dosage rate per Mean no.of dead scales at weeks after injection palm 0 2 4 6 8 12 Actara 25WG 10g.p (2.5g.a.i) 0.4 (0.9) 6.2 (2.6)AB 9.3 (2.5)AB 9.1 (2.7)A 4.6 92.6)A 4.7 (2.3)AB Actara 25WG 8g.p (2g.a.i.) 0.94 (1.2) 5.6 (2.5)AB 4.0 (2.1)ABC 5.4 (2.5)AB 3.9 (2.1)AB 3.8 (2.1)BC Actara 25WG 6g p (1.5g. a.i) 0.97 (1.1) 4.1 (2.1) BC 2.9 (1.8)C 4.4 (2.2)AB 3.1 (1.9)AB 1.9 (1.5)CD Confidor 200SL 20ml (4g. a.i) 1.6 (1.5) 8.8 (3.1)A 6.6 (2.7)A 5.9 (2.5)AB 4.0 (2.1)AB 6.7 (2.7)A Confidor 200SL 15ml (3g. a.i) 0.6 (1.0) 2.9 (1.9)BCD 4.1 (2.1)ABC 4.7 (2.3)AB 1.2 (1.3)AB 3.4 (2.1)BC Confidor 200SL 10ml (2g. a.i) 1.0 (1.2) 1.4 (1.0)D 3.2 (1.9)BC 3.2 (1.9)B 3.2 (1.9)BC 1.7 (1.5) CD Untreated control water only 0.9 (1.2) 1.4 (1.3)D 0.95 (1.2)D 0.73 (1.1)C 0.5 (1.0)C 1.3 (1.3)D

SE± 0.16 0.22 0.17 0.19 0.24 0.17 C.V% 23.3 18 14.4 15.04 22.0 15.5 -Data in brackets were √x+0.5. -Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

Table (10) Mean biweekly percentage mortality of adult females and immature stages of green pit scale insect from trees treated with different insecticides (using trunk injection method) at Elgaba scheme season 2003/2004. A: Adult Females % Mortality of scales at weeks after injection Insecticide Dosage rate/ palm 0 2 4 6 8 12 Actara 25WG 10g.p (2.5g.a.i) 9.6 (18.1) 100 (95.6)AB 100 (99.2)A 100 (97.2)A 100 (97.9)A 100 (92.4)A Actara 25WG 8g.p (2g.a.i.) 13.3 (21.4) 100 (91.2)AB 99.3 (85.2)BC 100 (91.3)AB 99.3 (85.3)B 98.5 (82.8)BC Actara 25WG 6g p (1.5g. a.i) 14.3 (22.2) 98.3 (82.5)BC 93.6 (75.3)CD 94.6 (76.5)C 86.8 (68.7)C 92.7 (74.3)CD Confidor 200SL 20ml (4g. a.i) 11.4(19.7) 100 (99.6)A 100 (99.6)A 100 (99.8)A 100 (92.9)AB 100 (99.2)A Confidor 200SL 15ml (3g. a.i) 13 (21.1) 94.6 (76.4)C 99.9 (89.9)AB 100 (90.1)AB 90.7 (72.3)C 100 (90.0)AB Confidor 200SL 10ml (2g. a.i) 12 (21) 91.9 (73.5)C 90.4 (72)D 95.9 (78.3)BC 79.8 (63.3)C 88.3 (70)D Untreated control water only 11 (20.2) 8.3 (16.7)D 10.7 (19.1)E 14 (22.0)D 23.9 (29.3)D 25.1 (30.1)E

SE± 1.99 3.77 2.89 3.72 3.34 2.62 C.V% 16.8 8.5 6.5 8.1 8 5.9 B: Immature stages Actara 25WG 10g.p (2.5g.a.i) 14.4 (22) 100 (99.6)A 100 (99.7)A 100 (99.4)A 100 (95.6)AB 100 (98.1)AB Actara 25WG 8g.p (2g.a.i.) 16.5 (24.1) 100 (96.8)A 100 (92.5)AB 100 (92.4)B 99.8 (88)AB 99.6(86.6)ABC Actara 25WG 6g p (1.5g. a.i) 15.3 (23) 100 )93.8)AB 100 (91.3)B 99.9 (88.7)B 91.2 (72.7)CD 99.2(85)C Confidor 200SL 20ml (4g. a.i) 13.4 (21.5) 100 (99.2)A 100 (99.6)A 100 (99.7)A 100 (99.7)A 100 (99.1)A Confidor 200SL 15ml (3g. a.i) 17 (24.4) 99.2 (85.2)BC 100 (92.7)AB 95.4 (77.7)C 98.4 (82.7)BC 99.4 (85.7)BC Confidor 200SL 10ml (2g. a.i) 15.4 (23.1) 97.9 (81.7)C 96.7 (79.6)C 87.2 (69)D 78.4 (62.3)D 94.4 (76.3)C Untreated control water only 9.3 (17.8) 19.9 (26.5)D 21.4 (27.6)D 21.6 (27.7)E 22.8 (28.5)E 25.5 (30.3)D

SE± 1.46 2.57 2.12 1.45 3.93 3.56 C.V% 11.3 5.4 4.4 3.2 9.0 7.7 -Data in brackets were arcsine transformed. -Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

Table (11) Mean biweekly total mortality of green pit scale insect from tree treated with different insecticides (using trunk injection method), at El Golid, season 2004/2005. Insecticides Dosage No. of dead scales at weeks after injection rate/palm 0 2 4 6 8 12 Actara 25WG 10g.p (2.5g.a.i) 0.51(1.0) 7.7 (2.8)A 8.5 (3.0)A 5.7 (2.5)A 3.7 (2.0)AB 5.3 (2.4)A Actara 25WG 8g.p (2g.a.i.) 0.71 (1.1) 3.5 (2.0)B 4.3 (2.2)BC 3.1 (1.9)CD 2.4 (1.7)BC 3.4 (1.9)BC Actara 25WG 6g p (1.5g. a.i) 0.6 (1.1) 2.7 (1.8)BCD 3.1 (1.9)C 2.4 (1.7)DE 1.3 (1.3)CD 2.3 (1.7)CD Rinfidor 20%SL 20ml (5g. a.i) 0.7 (1.1) 6.3 (2.6)A 5.8 (2.5)B 4.3 (2.2)AB 3.5 (2.0)AB 3.9 (2.1)AB Rinfidor20%SL 15ml (4g.a.i) 0.9 (1.2) 3.3 (1.9)BC 3.1 (1.9)C 2.4 (1.7)DE 2.5 (1.7)BC 3.1 (1.9)BC Rinfidor20%SL 10ml (3g.a.i) 0.9 (1.2) 1.8 (1.5)D 1.5 (1.4)D 1.7 (1.3)E 1.2 (1.3)CD 2.3 (1.7)CD Comodor20%SL 20ml (5g.a.i) 1.1 (1.3) 6.8 (2.7)A 5.4 (2.4)B 4.8 (2.3)AB 4.3 (2.2)A 4.3 (2.2)AB Comodor20%SL 15ml (4g.a.i) 0.9 (1.1) 3.9 (2.1)B 3.5 (2.1)C 2.9 (1.8)D 2.6 (1.8)ABC 3.1 (1.9)BC Comodor20%SL 10ml (3g.a.i) 1.1 (1.2) 2.1 (1.6)CD 1.8 (1.5)D 2.4 (1.7) DE 1.9 (1.5)CD 2.4 (1.7)CD Confidor 200SL 20ml (5g.a.i) 1.1 (1.3) 7.3 (2.8)A 7.9 (2.9)A 4.2 (2.2)AB 3.9 (2.1)AB 3.1 (1.9)BC Confidor 200SL 15ml (4g.a.i) 0.9 (1.1) 3.5 (2.0)B 4.3 (2.2)BC 1.9 (1.5)E 1.4 (1.4)CD 2.1 (1.6)CD Confidor 200SL 10ml (3g.a.i) 1.0 (1.2) 2.1 (1.0)D 3.1 (1.9)C 1.7 (1.5)E 1.0 (1.2)D 1.5 (1.4)DE Untreated control water only 0.9 (1.1 0.5 (1.0)E 0.7 (1.1)E 0.5 (1.0)F 1.0 (1.2)D 0.5 (1.0)E

SE± 0.14 0.10 0.11 0.1 0.13 0.12 C.V% 24.6 8.7 9.2 8.4 14.1 11.7 -Data in brackets were √x+0.5. -Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

Table (12) Mean biweekly percentage of adult females of green pit scale insect from trees treated with different insecticides (using trunk injection method) at El Golid, season 2004/2005. Insecticides Dosage % Mortality of scales at weeks after injection rate/palm 0 2 4 6 8 12 Actara 25WG 10g.p(2.5g.a.i) 23.1 (28.7) 91 (72.8)A 98.6 (88.4)A 95.8 (76.6)ABC 100 (98.5)A 99.6 (86.5)A Actara 25WG 8g.p (2g.a.i.) 22.9 (28.5) 89.0 (70.8)A 91.5 (73.4)ABCD 87.2 (69.0)ABC 100 (98.6)A 100 (95.7)A Actara 25WG 6g p (1.5g. a.i) 27.0 (31.3) 69.4 (56.4)BC 87.7 (69.5)ABCD 65.3 (53.9)CD 100 (97.9)AB 99.8 (87.2)A Rinfidor 20%SL 20ml (5g. a.i) 13.6 (21.7) 89.2 (70.8)A 80.0 (97.0)ABC 100 (98.0)A 100 (99)A 100 (97.7)A Rinfidor20%SL 15ml (4g.a.i) 12.3 (20.5) 61.4 (51.6)C 77.2 (61.5)BCD 100 (99.0)A 98.9 (84.4)AB 100 (99.2)A Rinfidor20%SL 10ml (3g.a.i) 20.7 (27.1) 51.6 (45.9)C 72.4 (58.0)CD 98.7 (83.7)ABC 91.2(80.5)AB 97 (80)A Comodor20%SL 20ml (5g.a.i) 23.2 (28.8) 88.7 (70.4)A 97.6 (81.2)ABC 100 (94)AB 100 (99.2)AB 100 (99.5)A Comodor20%SL 15ml (4g.a.i) 14.7 (22.6) 66.8 (54.8)C 85.3 (67.3)ABCD 100 (91)AB 96 (78)BC 100 (98)A Comodor20%SL 10ml (3g.a.i) 13.7 (21.7) 50.9 (45.5)C 67.0( 54.0)D 78 (62.0)BC 92 (74.7)AB 100 (91.9)A Confidor 200SL 20ml (5g.a.i) 19.9 (26.3) 86.6 (67.7)AB 100 (91.0)A 100 (99)A 100 (99.4)A 100 (99.7)A Confidor 200SL 15ml (4g.a.i) 27.9 (31.9) 70.4 (57.0)BC 99.5 (86.0)AB 98.7 (83)ABC 100 (99.5)A 100 (98)A Confidor 200SL 10ml (3g.a.i) 11.9 (20) 70.6 (57.2)BC 84.8 (67.1)ABCD 89.1 (71.9)ABC 89.2 (71)B 100 (91)A Untreated control water only 17.3 (24.6) 15.0 (22.0)D 19.0 (24.9)E 25.7 (30.6)D 19.2 (26)C 13.3 (21.4)B

SE± 3.76 3.47 7.13 9.75 6.32 6.26 C.V% 25.4 10.5 17.8 21.6 12.8 12.3 -Data in brackets were arcsine transformed. -Means with letter(s)} in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

Table (13) Mean biweekly percentage mortality of immature stages of green pit scale insect from trees treated with different insecticides (using trunk injection) at El Golid, season 2004/2005. Insecticides Dosage % Mortality of scales at weeks after injection rate/palm 0 2 4 6 8 12 Actara 25WG 10g.p (2.5g.a.i) 8.2 (16.6) 100(99.3)A 100(98.4)A 100(99.6)A 100(98.1)A 100(98)A Actara 25WG 8g.p (2g.a.i.) 20.8 (27.1) 97.8 (81.4)ABC 100(95.2)A 100(99.6)A 100(96.3)A 100(96.2)A Actara 25WG 6g p (1.5g. a.i) 2.5 (9.1) 96.3(78.9)BC 100..(92.1)A 100(99.1)A 98.6(83.3)B 99.7(86.9)A Rinfidor 20%SL 20ml (5g. a.i) 23.2 (28.8) 100(99)A 100(95.4)A 100(98.2)A 100(99.2)A 100(97.5)A Rinfidor20%SL 15ml (4g.a.i) 9.9 (18.3) 99.9(88.3)AB 100(97.7)A 100(98.9)A 100(97.8)A 100(99.2)A Rinfidor20%SL 10ml (3g.a.i) 4.5 (12.3) 85.5(67.6)C 100(90.7)A 98.2(82.3)B 100(99.3)A 100(97.2)A Comodor20%SL 20ml (5g.a.i) 25.6 (30.4) 100(99.5)A 100(98.5)A 100(99.3)A 100(99.2)A 100(98.5)A Comodor20%SL 15ml (4g.a.i) 1.5 (1.4) 100(99.4)A 100(98.4)A 100(96.2)A 100(98.6)A 100(99.1)A Comodor20%SL 10ml (3g.a.i) 0.4 (1.0) 97.9(81.6)ABC 100(95.2)A 100(90.9)A 100(98.7)A 100(99.5)A Confidor 200SL 20ml (5g.a.i) 25.2 (30.1) 100(99.3)A 100(99.3) A 100(99.6)A 100(99.4)A 100(98.A Confidor 200SL 15ml (4g.a.i) 11.7 (20.0) 100(98.9)A 100(98.8)A 100(99.4)A 100(99.4)A 100(99.4)A Confidor 200SL 10ml (3g.a.i) 12.4 (20.6) 100(97.3)A 100(98.1) A 100(95.3)A 100(99.2)A 63.5(52.8)B Untreated control water only 17.5 (24.8) 22.3(28.2)D 24.4(29.6)B 24(29.3)C 23.2(28.8)C 24.3(29.5)C

SE± 5.23 3.47 2.73 2.66 7.22 4.8 C.V% 10.5 6.6 5.2 5.0 14.1 45.3 -Data in brackets were arcsine transformed. -Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

Table (14) Yield and yield components of date fruits from trees treated with different insectices (using trunk injection) at Elgaba scheme, season 2003/2004. Insecticide Dosage rate/palm % ripe Fruit weight Fruit length Fruit diameter L/D ratio % seed/ Yield fruit (g) (cm) L (cm) D Fruit wt. kg/palm Actara 25WG 10g.p (2.5g.a.i) 100A 7.2A 4.9A 1.6 3.0 9.3D 109A Actara 25WG 8g.p (2g.a.i.) 93.3AB 6.8AB 4.9A 1.5 2.9 11.3BC 85.5ABC Actara 25WG 6g p (1.5g. a.i) 85BC 6.2B 4.3BC 1.7 2.8 12.7B 81.77ABC Confidor 200SL 20ml (4g. a.i) 100A 7.6A 4.7AB 1.6 3.0 10CD 103.67AB Confidor 200SL 15ml (3g. a.i) 86.7BC 7.4AB 4.6AB 1.6 2.9 11.7BC 63.67BCD Confidor 200SL 10ml (2g. a.i) 80C 7.0AB 4.5AB 1.5 2.8 12.3B 57.77CD Untreated control water only 48.3D 4.9C 3.9C 1.5 2.6 15.7A 28.3D

SE± 2.47 0.37 0.14 0.06 0.17 0.56 11 C.V% 5.0 9.5 5.6 6.5 9.9 8.1 25.1 Means with letter(s) in common are not significantly different at 5% level according to Duncan’s Multiple Range Test.

Table (15) Yield and yield components on date fruits from trees treated with different insecticides (using trunk injection method) at El Golid, season 2004/2005. Insecticides Dosage rate/palm %ripe fruit Fruit wt. (g) Fruit length Fruit L/D Ratio %seed per Yield (cm) L diameter. fruit wt. kg/palm (cm) D Actara 25WG 10g.p (2.5g.a.i) 100A 7.3A 4.6A 1.6A 3.0A 9.3FG 97.3AB Actara 25WG 8g.p (2g.a.i.) 86.7BCD 7.1AB 4.1ABCD 1.6A 2.6ABCD 12.7BCDEF 87.3BC Actara 25WG 6g p (1.5g. a.i) 70EF 6.9ABC 3.4EF 1.6A 2.1CD 8.3G 79 CDE Rinfidor 20%SL 20ml (5g. a.i) 90ABC 5.7ABCD 4.2ABC 1.4AB 3.0A 11.3DEFG 96 AB Rinfidor20%SL 15ml (4g.a.i) 83.3CD 5.4BCD 3.7BCDE 1.6A 2.3ABCD 14.7ABCD 86 BCD Rinfidor20%SL 10ml (3g.a.i) 65.1F 5.1CD 3.5DEF 1.4AB 2.6ABCD 16.3AB 72.7E Comodor20%SL 20ml (5g.a.i) 96.7AB 5.9ABCD 4.1ABCD 1.6A 2.6ABCD 9.7EFG 96.7AB Comodor20%SL 15ml (4g.a.i) 80CDE 5.1CD 3.7CDE 1.4AB 2.5ABCD 13.3BCDE 75.7DE Comodor20%SL 10ml (3g.a.i) 60F 4.7D 3.4EF 1.3B 2.8ABC 14.7ABCD 68E Confidor 200SL 20ml (5g.a.i) 100A 5.9ABCD 4.3AB 1.5AB 3.1AB 10EFG 99.7A Confidor 200SL 15ml (4g.a.i) 83.3CD 5.3BCD 3.6DE 1.6A 2.2BCD 11.7CDEFG 86.3BCD Confidor 200SL 10ml (3g.a.i) 78.6DE 4.2D 3.2DEF 1.4AB 2.2BCD 15.3ABD 68.7E Untreated control water only 50G 4.3D 3.1F 1.4AB 1.9D 18.3A 24.7F

SE± 3.15 0.51 0.18 0.07 0.21 1.13 3.28 C.V% 6.8 15.8 8.4 8.2 14.5 15.4 7.1 Means with letter(s) in common are not significantly different at 5 % level according to Duncan’s Multiple Range Test.

4.4 Economic feasibility of controlling the green pit scale insect with imidacloprid as Confidor 200SL. The partial budget analysis of using Confidor 200 SL in Northern Sudan is summarized in Table 16. Profitability of control of the green scale insect using Confidor gave marginal rate of return of 364 %. This indicates that every Sudanese pound (SDG) spent to control the insect may generate an extra net benefit of 3.64 indicating positive profitability of the package.

4.5.Varietal susceptibility The four Dates palm varieties under test showed different levels of infestation.Result in Fig.14; indicate that Gondeilla variety was the most susceptible.The infestation of Barakawi and Jaw were moderate, and the least affected variety was Waddlagi. The results were constant over months and in the four locations.

The number of living insects (female and immature stages) was not affected by inter cropping or without inter cropping although the least susceptible variety Wadlagi showed less number of living insects in date palm farms with inter cropping (less than 100 scale inset per leaf) compared with without intercropping during the four months which recorded more than 300 scale per leaf .The results showed that the infestation is not affected with the direction or the position of the leaves on the tree, although the highest population of the scales were found on the lowest leaves and on the south west direction of the tree.

Table (16): Economic analysis using confidor 200 SL to control the green scale insect in the Northern State (Based on survey conducted in 2007) Chemical Non- Difference control Control Cost of Irrigation (SDG/tree) 2.66 2.22 0.44**

(33) (34) Cost of Cleaning (SDG/tree) 1.16 1.09 0.07*

(14) (19) Cost of Harvesting (SDG/tree) 0.08 0.05 0.03**

(28) (39) Cost of Chemical (SDG/tree) 6. 25 0.00 6,25 Total cost (SDG/tree) 10.15 3.36 6.79 Productivity{Sack (100 kg)/tree} 1.29 0.84 0.45***

(31) (23) Average dates price (SDG/Sack) 70 70 70 Gross Benefits (SDG/tree) 90.3 58. 8 31.5 Net Benefits (SDG/tree) 80.15 55.44 24.71 MRR% 364

Figures between bracketsare the number of cases

*, ** and ***, symbols indicate the variable is statistically significant at 1%, 5% and 1% level of significance, respectively.

4.6. Natural enemies’ assoicated with the green pit scale insect in the Northern State, Sudan.

Monthly counts were conducted over a period of five months (April – December), 2006, covering the four mentioned varieties in the four infested locations.

The results showed that there were two species of predatory Coccinellids associated with date palm green pit scale insect in the different locations. The first was Cybocephalus dudichi and the second was Pharocymnus numidicus (plate 5 d). They were known as predators of white scale insects but their abundance with this insect show that they are general predators. The monthly mean total number of the adults of the two species was recorded as shown in Fig. (1) and Fig. (2) for Cybocephalus dudichi and Pharocymnus numidicus, respectively. The higher numbers were observed in months when the green pit scale was active (Fig. 3). The number of these species was low in winter (November – December); it was affected by the low number of the green pit scale insect. Fig. (4) Shows that the number was not affected in date palms orchards with or without intercropping. Other species were recorded like Chrysopa spp. and a predatory mite. Some adult females were attacked by a parasite because exit holes were found in the covers of the scales. Also some adult females became black with a black liquid like polyhydrosis.

2.5 2.5

2 2

Barakawe 1.5 Barakaw e 1.5 Gondeila Gondeila Jaw Jaw Wadlagai 1 Wadlagai 1

0.5 0.5

Meannumberofpredator/leaf 0 0 August September October November December August September October November December

With inter cropping Without intercropping

Fig.1: Mean number of Cybocephalus dudichi on four date palm varieties (with and without intercropping) at the study sites.

2.5 2.5

2 2

Barakawe 1.5 1.5 Barakaw e Gondeila Gondeila Jaw 1 Jaw Wadlagai 1 Wadlagai 0.5 0.5

0 0 August September October November December August September October November December Meannumberofpredator/leaf

With inter cropping Without intercropping

Fig.2: Mean number of Pharocymnus numidicus on four date palm varieties (with and without intercropping) at the study sites.

800 800

700 700 Barakawe Barakawe

600 Gondeila 600 Gondeila

500 Jaw 500 Jaw

Wadlagai Wadlagai 400 400

300 300

200 200

100 100 umber of living green scale insect/leaf

0 0 August September October November December August September October November December Mean n

With intercropping Without intercropping

Fig.3: Mean number of the living adults of the green pit scale insect on four date palm varieties (with and without intercropping ) at the study sites.

160 160

140 140 Barakawe Barakawe 120 120 Gondeila Gondeila

100 Jaw 100 Jaw

80 Wadlagai 80 Wadlagai

60 60

40 40

20 20

0 0 August September October November December August September October November December

Mean number of dead green scale insect /leaf With intercropping Without intercropping

Fig.4: Mean number of the dead adults of the green pit scale insect on four date palm varieties (with and without intercropping) at the study sites.

C. P. (P.P.D) in Algaba (2004) Treated trees (200,000) IPM package. Excellenent Results a. Results of ripe and unripe fruits collected b. Results of comperehenseve control from treated and untreated date palm trees. program at Elgaba Scheme using Confidor during April-June , 2004 (200,000 date palm were treated )

Yield and yield components: %Ripe fruit, F. wt., F.L, F.D., L/D ratio and % Seed/fruit wt. Yield kg/palm

Pharosymnus sp.

c. Yield and Yield components d. Expected natural enemies

Plate 5. Results of insecticides application and natural enemies’ Survey

5: DISCUSSION

5.1 The date palm tree

Palm tree is a sacred tree which plays an important role in the life of Sudanese and Arabs throughout the history. People not only benefited from dates fruits, but they benefited from all parts of that tree, including trunk, rachis, leaves, rachis base and fiber sheath as well as pits for animal nutrition.

In the last 20 years, this important tree however, did not receive attention by farmers as far as agricultural practices which resulted in low production and thus low income for farmers. This lead to the abandon of this important tree for economical reasons. It should be noted that date palm grown along river Nile in North Sudan, was impaired by close spacing, lack of proper and regular pruning, no fertilization, improper irrigation, water stress and water logging. This was due to drought spells which wiped out the region early in 1980 's followed by effects of flooding for prolonged time (1-2 months in 1985-1988-1998) and this might have changed the ecosystem of plant growth and rendered them to be sensitive to different pests and diseases as appeared now. In Sudan, the date palm green pit scale insect is consider as a key pest, Infestation has aggravated during the past two decades and crossed the natural barrier of Albaja desert northwards to affect large areas in Elgaba, and Old Dongola (450 km north of Khartoum) and recently spread to Artigasha island and Elburgaig scheme (600 km north of Khartoum) and the estimated number of infested palm trees is around one million. (Ahmed, 2007).

5.2 Control measures In recent decades, research centers world wide have made considerable progress in developing both fundamental and applied Integrated Pest Management (IPM). The fundamental aspects related to pest crop interactions, mathematical models and the population dynamics of pest organisms. Applied aspects include,

94 control measures, such as cultivation practices, plant resistance, biological control and the judicious use of agro-chemicals. The modern agricultural production in high yield and high quality significantly depends on the use of agrochemicals to control growth and pests.

In the past, and due to lack of indigenous knowledge of appropriate control measures adopted to control the date palm green pit scale insect, in Sudan , the treatment control efforts were not successful; hence the level of infestation steadily increased. Following intensive research efforts since the year 2000, this study identified a systemic insecticides of new generation, Neonicotinoid insecticides (thiamethoxam & imidacloprid) such as Confidor 200 SL and Actara 25 WG which proved high effectiveness in controlling the green pit scale insect in the infested trees, through integrated pest management starting with cultural practices or sanitary measures, supplemented with chemical control and impact of natural enemies together with plant quarantine legislations. A series of small scale experiments were undertaken in Elgaba scheme and El Golid area during seasons (2003/2004 -2004/2005) to evaluate the effectiveness of three systemic insecticides using two application techniques against the green date palm pit scale insect. A comprehensive program by Plant Protection Directorate (PPD) has been conducted in Elgaba scheme (April-June 2004) resulted in treatment of 200,000 date palm trees using the recommended package and gave very good results. By now (2008) large scale trials have been conducted in the other five locations El Golid area, Old Dongola, Elburgaig scheme, River Nile state and Elgaba Scheme

5.2.1 Soil application method The results of soil application experiments against the pit scale insect proved that both tested imidacloprid and thiamethoxam compounds reduced the number of the scale pest and they were significantly different from the control (untreated) through out the test period (12 weeks after application). The higher doses of thiamethoxam as Actara 18 g product / palm and imidacloprid as Rinfidor 200SL 95 and Comodor 200SL (35 ml product/palm) were similar in efficacy to standard insecticide Imidacloprid as Confidor 200SL. Resuts of this study confirmed the finding of Ahmed (2003) who evaluate the efficacy of Confidor 200SL and Furadan against the same pest in Elgaba scheme during (1999-2001). Results indicated that dead insect, % mortality (adults and immature stages) were significantly higher than in untreated control after two weeks. All insecticides lost their effectiveness after 12 weeks.The insecticides effectiveness were Confidor (35ml/palm), Furadan 5G (60g/palm) and Confidor (25ml/palm).

Date palms treated with higher doses imidacloprid (35ml) and thiamethoxam (18g) showed a high percentage of ripe fruits with no losses. They also showed the highest fruit weight (g) and the lowest percentage of seed/ fruit weight resulting in a higher yield compared to the untreated control. Fageer and Ahmed (2008) studied the impact of infestation of the green pit scale insect on production costs and productivity their finding revealed that, the proportion of farmers who produce less than half a sack/ tree/ year (about 50 kg) is 68% of the total farmers in the study area due to the infestation by the green scale insect and weak palm care.

The date palm treated with the high doses of thiamethoxam and imidacloprid, started re-growing, which was a clear indication that the pests damage had stopped and the palms were no longer under stress. This phenomenon was independent of the pesticide formulation applied to the palm. The increase in number of the scale pest on control and treated trees was slower in the trees treated with the higher doses compared with the lower doses, and these agreed with results obtained by Kehat et.al (1967) which stated that the chemicals that injured the females of the green date palm pit scale insect had a prolonged effect in preventing the reappearance of the young nymphal insars and thus scale insect population were renewed only at a much slower pace. It was observed that the treated trees remained free from termites, white scale insects and ant infestation. However, the two

96 insecticides had no effect against mites. The results were consistent over years and locations.

The date palm is also attacked by may other pests. The red palm weevil, the stem borer beetles and their larvae such as Orycet eleans, Phonopate frontalis, and Pseudophilus testaces and the principal sucking pest is the date palm cicada (Ommatissus binotatus libycus). All the above mentioned pests can be controlled with imidacloprid as confidor 5 GR or 200 SL. Two treatments with 60-100 g/palm or 15-20 ml in 10 L water /palm, applied to the soil around the trunk give adequate protection and it also proved to be very effective as a protective measure against new infestations for a period of more than six moths (Sherif, 1994).

Experiments were undertaken in Sao Paulo, Brazil, (Filippe et. al., 2005) to evaluate the efficiency of systemic insecticides, including imidacloprid, to control aphids and leafhoppers on young citrus plants after drench application of imidacloprid compared with thiamethoxam. The insecticides were found efficient control leafhopper Oncometopia facialis and the brown aphid Toxoptera citricida [T. citricidus] for 155 and 90 days, respectively. In a second experiment, the insecticides were applied in the field, by soil (granulated) and by drench (50 ml solution/plant). The control periods of O. facialis by aldicarb+imidacloprid was longer than aldicarb alone (15 g CP/nursery plant) which presented a shorter control period. For aphids, until 61 days, the control was over 95% for all treatments. There was no occurrence of this pest in further evaluations.

The efficiency of imidacloprid (0.35, 0.70 and 1.05 g a.i./plant) in controlling citrus leaf miner (P. citrella) infesting lemons was determined in a field experiment conductedinArgentina.Application of 0.35g a.i. imidacloprid /plant controlled citrus leaf miner up to 100 days after planting (Salas and Goane, 2003).

The principal sucking pest is the date palm cicada (Ommatissus binotatus Fieb.). The plant is damaged not only by the insect‘s feeding activity but also by its honeydew, which is colonized by fungi, and traps dust, thus reducing the tree capacity for Photosynthesis. The yield was also reduced by varies species of scales and mealy bugs. Very good control can be achieved with soil application of imidacloprid or thiamethoxam (Al-Jboory et.al, 2001). On the other hand, Askari and Bagheri (2006) attempted to control the same pest (Ommatissus binotatus Fieb.) using soil application of Imidacloprid 10% in three doses,12.5,15 and 20 ml per 10 liter of water .Sampling were done three,seven and 14 days after application Analytical study show that there is no difference between treatments and control .Results of this study matched with our finding .The lower doses of imidacloprid 20 and 25 ml/palm were not effective and the time for sampling for that study (≥14days) is not enough for insecticide transilocation in the tree.The same study indicate that, effective control obtained when imidaclprid injected with a dosage rate 12.5 ml /palm .

5.2.2 Trunk injection method Results of insect mortality, yield and yield components obtained from the two seasons (2003/2004 and 2004/2005) indicated that, trunk injection was an effective and reliable method for controlling the green pit scale insect. The higher doses treatments; Actara (10g), Rinfidor (20ml), Comodor (20ml) and Confidor (20ml) were superior to the lower doses and the untreated control in number of total dead insects and percentage mortality, even 12 weeks after application (the last count). Results of percentage mortality of adult females and immature stages showed the high efficacy of insecticides as reflected by the hundred percent mortality of adult female and immature stages during the second week after injection.

The same finding were obtained by Joseph et.al (2003 and 2007) when they test a trunk Micro-infussion of IMA-jet (imidacloprid) for control the Hemolock Woolly Adelgid (a tiny, piercing and sucking insect) that feed on Hemolock twings.Results indicate that, Adelgid mortality may occur with 14-28 days and continue for up to 2 years.Hemolocks respond to treatment with a resumption of growth. On the other hand, Smitly et.al (2006) success in controlling Emerald Ash Borer (Agrilus planipennis Fairmaire) infesting green Ash trees (Fraxinus pennsylvanica Marsh) with trunk injection using either imidacloprid (Mauget imidide and Arborjet IMA- jet), or orthen (Acecaps).Resluts indicate that the Arborjet trunk injection treatments with imidacloprid provided a high level of control (92-100%).Acecaps trunk injection containing acephate, gave 76% control.

Fernandes Cordova and Gallego (1997) found that oaks infested by oak scale insect were cured by injection with prepared capsules of 225ml Acephate or imidacloprid solution, these insecticides were effective in controlling the scale pest, moreover, they pointed out that grater than 79% control of oak scale was obtained when acephate and imidocloprid were injected at rates of 7.5g a.i. and 0.8ml per tree respectively. Mathen and Kurian (1977) pointed out that sevin at a concentration of 1% injected in coconut trunk cased 93% reduction in the infestation level of red palm weevil.

The distribution rates of the thiamethoxam as Actara 25 WG 24 h. post injection of 1 and 2 g a.i./palm (Al-Sammariae et.al,2006) showed that it distributed into the sap and it was detect in the injection side and also in the opposite side at different heights. The result indicated that thiamethoxam translocate rapidly into date palm trunk and reaches the leaves in a short time so it can be drown out of the findings that it can be employs as a fast chemical remedy against most palm insect pests.

As mentioned before, trunk injection requires the use of a systemic insecticide. It is a safe method wich affects the pest only without any side effect on natural enemies. Thus the method causes little adverse effects on the environment, when wide spray application with contact insecticides using aircrafts and heavy machinery had been conducted in areas like El Golid the pest recovered with in one year and spread from the target area to infest Elgaba scheme and Old Dongola (El Fahal et.al., 1993, Obied, 1997 and Ahmed, 2003). Furthermore, trunk injection protects the insecticide from adverse climatic factors. If we take into consideration that more than 60% of date palm trees in the Sudan are not irrigated, the use of trunk injection is very useful as an alternative solution to soil application method.

This method not only increases user’s safety, it also allows the work to be carried out in an extremely economical manner. The dose used is decreased to less than 50% compared to soil application. On the other hand, a three- man team can do the work, one man boring the hole, the second inserting the tube into the holes and the third inject insecticides and close tubes. Date palms treated by trunk injection, continued to develop normally during the past four seasons. No phytotoxicity had been observed till now in the treated trees. No insecticide residues have been detected either in dates, soil or grasses.

Insecticides are applied through direct injection into the trunk of the date palm to control the red palm weevil (Oihabi, 2003). The influence of injector size, tree species, and season on uptake of injected solution, uptake volume varied among species and injector size, but it usually increased with time. Uptake volume usually decreased as injector diameter decreased. In nonresinous species, the 6 mm (0.24 in.) injector gave the best results, but the 4 mm (0.16 in.) and the 3 mm (0.12 in.) injectors also gave acceptable results. Rubidium content increased over time in sampled needles. One day after injection, Rb+ was recovered in all tree sections, indicating a homogeneous distribution throughout the tree (Al-Jboory et.al 2001).

100

Distribution of injected materials throughout the tree is an important factor that may limit the use of the technique because chemicals may accumulate in one part of the tree and not in others. Many factors, including hole depth, injection placement, tree structure, and the number of injections per tree, affect the distribution of solutions (Sachs et al., 1977and Navarro et al., 1992). The injection method also affects distribution.Today, the tendency is to use low-pressure systems comprising individual devices on each injection point in order to control the quantity of material applied on each point (Whiley et. al., 1991; McClure, 1992 and Navarro et. al., 1992).The injector could be reduced in size to 4 mm (0.16 in.) in diameter for use in nonresinous species, but length must be increased to 70 mm (2.8 in.) to inject trees with thick bark and to reach the xylem without damaging the trunk.

Coniferous species are less effectively injected than angiosperms (Sachs et .al., 1977 and Reil, 1979). The difference is explained by the wood structure. Conifer xylem is composed primarily of tracheids with greater resistance to water movement than angiosperms, in which the xylem contains large-diameter, vertical vessels. In addition, some coniferous species produce resin in response to tree wounds, which may affect water uptake. For these reasons, trunk injections in conifers are less frequent than in angiosperms, and less information is available on the factors affecting uptake and distribution of injected solutions in these species.

Joseph et.al (2007) stated that, uptake occurs when trees are transpining.The environmental conditions that favor uptake are modrate temperature, adequate soil moisture and high humidity.Generally hot weather and dry soil conditions will results in a reduced rate of uptake.Micro-infusion time varies depending on the season, time of day, envirnmental conditions and tree health.The average uptake time for hemolock treatment is 30 minutes. So the correct time of injection (April- June) and cultural practices (removal of the dead leaves and the highly infested

101 leaves in the lowest rows and normal irrigation) recommended by our study are conformed by these findings.

Riad et.al (2007) in Irag designed local tunk injector for date palm tree. Many injectors world wide were manufacured for that purpose, such as Arbocap (www.arbocap.net) .The correct use as follows: 1) Preparing the insecticide 2) Charging the containers spring-machanim, aspirate up to the 40ml mark and aspirating will be continue a further 10 ml of air. 3) A hole in the trunk (to a depth of 3 cms approx.) will be drilled using a 3.5 mm drill hit for steal. 4) Arbocap will be inserted to a depth of 0.5 cm using rubber or plastic tipped hammer.5) Pressure will be produce by freeing Arbocaps spring-mechanism. 6) After complete absorption of the chemical Arbocap will be extracted and the hole will be disinfected.

Imidacloprid and thiamethoxam application through trunk injection is highly economical, as indicated that, the best doses of each compounds (20ml / tree and 10g / tree for imidacloprid as Confidor and thiamethoxam as Actara respectively) was lower the dose used in soil application method (35ml / tree and18g/tree ) by 57% and 55% for imidacloprid and thiamethoxam ,respectively.

Therefore the current work support the believes that there is a remarkable opportunities to inject Actara and other systemic pesticides directly in palm trunk and it will translocate in appropriate time and can fit well with date palm pests control program. One hole and one injection at adequate concentration could be enough to distribute Actara in palm tree within less than 24 hours could obtain efficient curing concentration.

5.2.3 Residues analysis of the tested compounds

The pesticide trunk injection technique which looks environmentally sound is widely demonstrated in date palm pest control programs. The success of this

102 technique based on the ability of the injected pesticide to translocate in palm sap (xylem and phloem) and provides an adequate concentration levels within appropriate time to keep the pest infestation intensity below the economic threshold.

Rinfidor 20% SL, Comodor 20% SL and Confidor 200 SL are formulation of imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazoldin-2-ylideneamine)]. Results of residue analysis indicated that, the residues of imidacloprid and its metabolites were below the detection limit (0.09 µg) in all samples analyzed. The Rf of imidacloprid was 0.53. This result indicated that the usage of Rinfidor 20 % SL, Comodor 20 % SL and Confidor 200 SL at the rate of 35 ml/ tree on the date palms are safe for human consumption.

According to the TLC results the Rf value for thiamethoxam standard was 0.56. The minimum detectable amount of thiamethoxam standard was 0.1 µ g . The recovery of the method was 85 % No residues of Thiamethoxam and metabolites were detected in all samples examined. Therefore, it is concluded that the use of Actara 25 WG on date palms may be safe if used at the recommended dose. It is known that rapid metabolism of thiamethoxam occurs in plants with two main major metabolites, which are of no toxic effect. In the field soil degradation of thiamethoxam is fast with half-life about four weeks. It gives one major metabolite and finally mineraled to carbon dioxide (Albert and Naeun, 2000).

Results of the date samples in Dammam area in Saudi Arabia collected after 6 weeks from treatment with Confidor 5 G at100 g /tree and 20 ml /tree for control the Red Palm Weevil, did not show any Confidor residues (Alawi, 1993). Results of the analysis of that study were illstrated in appendix (8).The study recommend that, these chemicals can be used before six weeks from the date of harvesting of fruits (Sherif, 1994).

103

Speed translocation of the systemic insecticide thiamethoxam (Actara 25GW) was investigated (Al-Sammariae et.al,2006) post injection of 4, 8, and 12g which represent 1, 2 and 3g a.i. (active ingredient) per plant moreover; the concentrations in sap, leaves and dates were monitored at different intervals. The insecticide qualitative and quantitative analysis were determined by employing ELISA and HPLC techniques. The results revealed following the injection of 12g/palm that Actara moved up in palm trunk sap at a rate of 2.8 m/h and the concentrations in pith and sap which been collected from sampling pore (1.4m above injection point) were 0.64 ppm and 2.939 ppm after 30 and 90 minutes respectively, this indicate that actara rapidly moved out of the injection point and diffused into the palm sap. On other hand the insecticide was detect in leaves (0.093ppm) and in dates (0.016ppm) at 240 minutes post injection and being 0.022ppm and 0.008ppm after 33 days respectively.

5.3 Economic feasibility of controlling the green pit scale insect with imidacloprid as Confidor 200SL. Profitability of control of the green scale insect using Confidor gave marginal rate of return of 364 %. This indicates that every Sudanese pound (SDG) spent to control the insect may generate an extra net benefit of 3.64 indicating positive profitability of the package.

The results of the t-test revealed that, there is highly significant difference (1%) in productivity between chemical control and non-control. More over, there is a significant difference at 5 percent level of significance for irrigation and harvesting costs and at 10 percent level of significance for cleaning.It could be concluded that, chemical control is more rewarding compared to non control regarding productivity as well as net benefits.

In addition to the direct benfits from using this package, farmers may increase their yield by cleaning and scheduled irrigation of their gardens (as the package 104 recommended) and by saving irrigation water as a result of changing the traditional method of irrigation (flood method) to direct irrigation (using irrigation basins round the date palm trees) and then reduced the expected diseases which are active in humid conditions.

It becomes clear that date palm production and plantations considerably deteriorated in the last years (Elshibli, 2008). Fluctuation in climatic and environmental conditions had its role in spread of insect pests and plant diseases. Consequently, these factors contributed to poor yield and low productivity of palms in the Northern States of Sudan (Nixon, 1967 and Osman, 1992).

A survey on dates production, storage and marketing was conducted in the Northern States of Sudan (Ali et. al., 1998).Data collected revealed that the system of ownership depends mainly on inheritance, which results in poor cultural practices particulary irrigation. The intercropping of legumes which improve guality and yield was practiced up to 50%.The improper traditionally practiced methods of date’s harvest, handling, drying and storage coupled with the absence of quality standards for the marketing system lowered the quality of dates.

5.4 Varietal susceptibility The four Dates palm varieties under test showed different levels of infestation. Gondeilla variety was the most susceptible. The infestation of Barakawi and Jaw were moderate, and the least affected variety was Waddlagi.

All the variety studies in the Sudan were conducted on white scale.Nasr (1982) reported that, in the Sudan, Medina and Wad-Katib varieties sustained the highest number of white scales per leaflet .The least susceptible variety was found to be Jaw. The susceptible varieties were those having broader leaflets.Osman (1992) reported that Moshrig and Gondiella varieties have comparatively less number of leaflets per frond, followed by barakawi and Jaw, while Tamouda possessed the 105 highest number. Ali (1989) stated that the Gondiella and Moshrig have comparatively larger size of leaflets, followed by Jaw and Barakawi, while Tamouda possessed the smallest size of leaflets .Mohamed (1991) concluded that, the most susceptible varieties were those having comparatively less number of leaflets per frond and a larger size of leaflets. As indicated by Alhafidh et al. (1981) this character may influence the degree of light intensity and other micro- environmental factors.

5.5 Natural enemies’ assoicated with the green pit scale insect in the Northern State, Sudan. The survey revealed the exsistence of two species of predatory Coccinellids associated with date palm green pit scale insect in the different locations. The first was Cybocephalus dudichi and the second was Pharocymnus numidicus. They were known as predators of white scale insects (Schmutterer, 1969., Nasr, 1982 and Ali, 1989) but their abundance with this insect show that they are general predators. The monthly mean total number of the adults of the two species was recorded for the two spiecies. The higher numbers were observed in months when the green pit scale was active. The number of these species was low in winter (November – December); it was affected by the low number of the green pit scale insect.

Other species were recorded like Chrysopa spp. and a predatory mite. Some adult females were attacked by a parasite because exit holes were found in the covers of the scales. Also some adult females became black with a black liquid like polyhydrosis.

None of the natural enemies associated with the scale Asterolecanium phoenicis Rao, was reported before 1967, even in catalogues of parasites and predators (Thompson, 1950; Thompson and Simmonds, 1964). Kehat (1968) reported that females and nymphs of the pit scale, Asterolecanium phoenicis Rao., were highly resistant to attack by the Coccinellid predator, Pharoscvmnus numidicus Pic., due to

106 their hard scale coverings. Yinon (1969) reported that the Asterolecaniids, the soft scales, the mealy bugs in addition to the armored scales, constitute the host range of the Coccinelled predator, Chilocorus bipustulatus L. The intensity of predation on the Asterolecanium phoenicis Rao. was only one-third the intensity of predation on the armored scale insects.

In Sudan, Ali (1989) reported that, no specific natural enemies were observed associated with this pest. However, some females were attacked by an endoparasite which failed to emerge from the scale but the ongoing research in Dongola Research Station succeded to isolate this parasite as a wasp belonging to hymenoptera, Aphytis spp.,and it was send to specialized center for idindification. An unidentified mite was found associated with both the green date scale and the white palm scale.The catalogues of Thompson (1950) and Thompson and Simmonds (1964) reported parasites and predators on other species of the genus Asterolecanium with varying degrees of parasitism and predation in some biological control attempts that were carried out. The majority of the natural enemies reported were considered inefficient and some were reported to have reduced value.

In general, scales are often well controlled by natural enemies, especially when predator and parasite activities are not disrupted by ants or applications of broad- spectrum insecticides such as Carbaryl, Malathion, or pyrethroids applied to control other pests. (Carvalho et al., 2006).

Depending on the extent to which biological control has been disrupted, it may take several months of conservation efforts before scale populations are reduced by biological control. If current levels of scales are intolerable, it is recommended to use a short residual low toxicity compound such as oil or insecticide to reduce scale populations while conserving natural enemies which is the strategy recommened by this study.

107

6: CONCLUSION AND RECOMENDATIONS

Conclusion

1- Soil application and trunk injection of imidacloprid (Confidor 200SL, Rinfidor 20% SL and Comodor 20%SL) and thiamethoxam (Actara 25WG) were highly effective in controlling the green pit scale insect. 2-They proved to be very effective as a protective measure against new infestation. 3-The two methods of application do not require anyexpensive machinery or labour for application. They can be safely applied. 4-Trunk injection truly effective and reliable method for controlling the green pit scale insect, with minimal environmental impact. 5- The two methods of application are highly economical and safe for the user and appear to be safe for the beneficial insects. 6- Date palms treated with different insecticides using the two methods, developed normally during four seasons. No phytotoxicity has been noticed in the treated trees. 7- The tested insecticides checked termites and many other pests, but did not affect mites. 8- Date palms are of major socioeconomic and social importance in the Northern State, but date palm is still grown in Sudan by convential methods without attention to irrigation, fertilization, or other cultivation practices. 9- Date palm production and plantations considerably deteriorated in the last years as a result of biotic and abiotic stresses, among which the green pit scale is the most important.

108

RECOMMENDATIONS

Based on the results, the following insecticides with given dosage rates are recommended for control the date palm green pit scale insect,using two methods of application:

1- Soil application: a) Confidor 200SL (imidacloprid) 35 ml product / tree (7g a.i.) b) Actara25WG (thiamethoxam) 18g product / tree (4.5 g a.i.) c) Rinfidor 20%SL (imidacloprid ) 35 ml product / tree (7g a.i.) d) Comodor 20%SL (imidacloprid) 35 ml product / tree (7g a.i.) The following cultural practices must be conducted before application: a) Pruning; removal of the dead leaves and the highly infested leaves in the lowest rows. b) Raising earth around the date palm trees to facilitate irrigation. c) Pre-watering and normal irrigation after application.

2- Trunk injection: a) Actara25WG (thiamethoxam) 10g product / tree (2.5 g a.i.) b) Rinfidor 20%SL (imidacloprid) 20 ml product / tree (4g a.i.) c) Comodor 20%SL (imidacloprid) 20 ml product / tree (4g a.i.) d) Confidor 200SL (imidacloprid) 20 ml product / tree (4g a.i.) Removal of the dead leaves and the highly infested leaves in the lowest rows and normal irrigation must be applied.

3- Varietals Susceptibility and natural enemies

a) Cultivation of Wadlagi variety is recommended in the infested areas. b) Further studies are needed to confirm the efficacy of the natural enemies

109

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Appendices

Appendix: 1

The Study Area -Northern State 1-Geography, Population and Agriculture Northern State of the Sudan lies in the desert zone between latitudes 16°-22°N and longitudes 24° - 34°E. Bordered by the Arab Republic of Egypt from the north, River Nile State in the east, North Kordofanian State in the south and North Darfur and Libya in the west.

The total area of Northern State is 347 000 square kilometers and it is dominated by the desert climate hot dry summer and cold dry winter. Annual rainfall ranges from zero in the north to 100mm in the southern part of the State and rain is distributed during the months from July to September (MFG, 1999). The summer season extends from April to September with temperature ranging between 30°C and 48°C, whereas the winter season extends from October to March with temperatures ranging from 3°C to 20°C.

The topography of the State is flat in most of its parts, except for some hills in the northern and central parts, and vast plains of sand and stone characterize this area. The River Nile is the main hydrological and geomorphologic feature crossing the Northern State from south to north. Some “Wadis” also exit like wadi Almalk, Wadi Almogaddam and wadi Abusara, which are annually flooded by the Nile (MFG, 1999).

Underground water is abundant where the Nubian Basin runs across the State with annually replenishable fresh water. The depth of water ranges from 30.5 to 91.5 m (100-300 ft). Plant vegetation is very poor or almost absent except for very narrow strip along the banks of the Nile where some grass and some trees (palm and acacia)

125 are found. The most important natural problem facing the State is that of desert creep or desert encroachment, which threatens most of the agricultural fertile lands. Erosion of the Nile banks “hadam” is another problem in the area, which annually cuts areas of fertile land and some sand into the Nile water stream during the flooding season, forming what are known as sand islands in the Nile.

2-Population The total population of the State was 510 463 in 1998 (MFG, 1999 report), and population density was 1.4 persons per square kilometer. About 86% of the total population (446 445 persons) live in rural areas and the remaining 14% live in urban centers mainly Dongola, Merewe and Halfa. There are great variations in the distribution of population among localities. About 47% of the total population is in Dongola province alone (238 780 persons), 25% is in Merewe province, 16% in Debba province and only 12% is in Halfa province (MFG, 1999).

3-Agriculture The Northern State of Sudan is privileged by a very distinct winter season, which extends for seven months. This characteristic in particular has rendered the State one of the most promising regions in the Sudan. The State has a comparative advantage of successfully growing winter and summer crop and vegetables that can be planned to match the peak demand periods in the internal and external markets. Arable land in the Northern and the River State is estimated to be 4.8 million feddans (2.016 million hectares), one feddan is 0.42 hectare. In season 2001/02 the total area cultivated in the Northern was 233 848 feddans (98216.2 ha) and the main crops were wheat (30% of the cultivated area), faba bean 27%, and maize, onion, alfalfa, orchards cereal forage (sorghum), spices, sunflower and fenugreek accounted for 43% of the total area.

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4-Irrigation water Irrigation water is the most expensive single input for agricultural production in the Northern State. It is obtained from the Nile or lifted from underground water using diesel-operated pumps. The most predominant pump size is the small size with discharge pipes having diameter of 7.6 to 10.2 cm (3-4 inches). They are scattered all over the state along the banks of the Nile and in most parts of the state (State Ministry of Agriculture, Northern State, 2002).

5-Soils The soils of Northern state are divided into two main groups, namely, soils of recent flood plain and soils of the high terrace, Izzaldin (1983). Soils of the recent flood plain include the “Gerif” and “Gureir” soils beside the basin soils.

The Gerif soils are distributed along the banks of the Nile and contain high amounts of silt of recent origin, which is renewed annually by inundation from the Nile during its flood seasons. After the subsidence of flood, crops are grown without irrigation, thus making use of the residual moisture. These soils are of high water holding capacity and plants can utilize most of the moisture in the soil profile (Karouri, 1978), reported by Izzaldin (1999).

The Gureir soils, which occur near the banks and adjacent to the Gerif soils, are subjected to flooding by moderately high floods. They are similar to finer texture. They are fertile free working alluvial loams and, when irrigated are one of the most productive soils in the Sudan (Karouri, 1978), reported by Izzaldin et.al (2000).

Basin soils are alluvial deposits. They are characterized by comparatively high clay content, low salinity except the marginal parts, where sodicity is occasionally observed (Izzaldin, 1983).

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The high terrace soils constitute the largest proportion of the land available for future agricultural expansion. These soils suffer to a considerable extend from salinity and /or sodicity.

The soils of Northern State are generally alkaline in reaction having pH values ranging between 7.2 and 8.6. Gerif and Gureir soils are the most fertile whereas, the high terrace soils are the least fertile (Ibrahim, 1995)

6- Dongola - Debba Area 6.1-Climatology: Dongola area is true desert with extremely high temperatures and solar radiation in summer, low temperatures in winter, scarce rainfall, and high wind speed. The diurnal range of temperature is wide all the year round. The mean maximum and mean minimum temperatures are 36.4°C (97.5°F) and 18.2°C (64.8°F), respectively. Temperatures as low as 1°C (33.8°F) have been recorded. The climate is hyper arid with a vapor pressure of only 10.8mb and a relative humidity of less than 20%. The mean bright sunshine duration is 10.5 hours (at 87% of the possible hours). Clouds are generally rare during the day. Solar radiation is as high as 25.9 MJm-2 day-1 in May. Rainfall is scarce with a mean annual amount of 12.3 mm. Wind prevails from the north to the south with a mean speed of 15.7 km hr-1.

6.2- Physiography: In Dongola area, a basement complex of Precambrian metamorphic rock is overlain by the Nubian sandstone, which is known for its abundant under groundwater (Izzaldin, 1983).

Alluvial deposits dominate the flood plains along the Nile banks. Away from these banks, sand dunes rest upon smooth ground sloping gently towards the Nile. The land is flat due to wind erosion and the nature of underlying rocks (Izzaldin, 1999). The sand dunes and wind hammocks characterize the geomorphology of the area.

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Appendix: 2 Trade and common names, toxicity and suppliers of the tested insecticides. Trade Common name Chemical name Toxicity Suppliers name Acute oral Acute dermal Acute Skin Principal Company Local Agent

LD50 (mg / kg ) LD50 (mg/kg) Inhalation irritation

(Rat) (Rat) LC50 4h. (Rat) (Rabbit)

Actara thiamethoxam 3-(2-chloro-thiazol-5- 1563 >2000 3720 Not irritant Syngenta ySyngenta (Sudan) 25WG ym ethyl-[1,3,5] (Switzerland) oxodiazinan-4ylidene- N-nitroamine Rinfidor imidacloprid 1(6-chloro-3-pyridyl 450 >5000 5323 Not irritant Agromen chemical Riham 20%SL meth yl)-N- Co LTD (China) International Co. nitroimidazolidin-2- LTD ylideneamine Comodor imidacloprid 1(6-chloro-3-pyridyl 450 >5000 5323 Not irritant Madmac (Jordan) Green Deel 20%SL meth yl)-N- nitroimidazolidin-2- ylideneamine Confidor imidacloprid 1(6-chloro-3-pyridyl 450 >5000 5323 Not irritant Bayer (Germany) MADCO 200SL meth yl)-N- nitroimidazolidin-2- ylideneamine

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Appendix: 3

Climatologically Normal (1997-2006) for Dongola Station

Element Temperature C° RH Rainfall ETo Month Max. Min. % mm/Month mm/day January 27 8.5 35 0.3 5.8 February 29.4 9.8 30 TR 6.3 March 33.8 13.9 23 TR 8.5 April 38.6 18.5 21 TR 10.8 May 41.8 22.3 18 TR 12 June 43.4 24.7 17 0.5 12.7 July 42.2 25 21 TR 10.8 August 41.8 25.2 22 3.2 11.1 September 39.8 24.7 21 7.7 11.2 October 38.4 20.4 25 0.1 9.9 November 32.1 14.8 32 0.5 7.1 December 28.3 10.2 36 TR 4.9

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Appendix: 4 Climatologically Normal (1997-2006) for Dongola Station Showing both Maximum and Minimum Temperatures Graph

y h t r r c ly e er r une Ju ua April May J tob Ma c emb Jan Augus O February Month ov September N Climatological Norms (1997-2006) for Dongola Station

Temperature Max. Temperature Min. RH % Rainfall mm/Month ETo mm/day

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Appendix: 5

The long term temperature means number versus last two years in Dongola area.

Temperture 2008

Long -term 33 average 95 -04

Average temp. (10 days interval) 2008 28 Average temp. (10 days interval) 2007

Temperature (C) Temperature 18

13 123456789101112131415161718192021 Time (10-day intervals) from 22 October

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Apendix: 6 Other insect pests of date palm Because they are minor pests and/or do not cause damage of economic importance, the following pests are not detailed in the review; - Fig Beetle, also called Green Fruit Beetle, Cotinis texana (Casey); - Indian Meal Moth, Plodia interpunctella (Hbn); -Almond Moth, Ephestia calidella; -Lesser Date Moth also called Hmira, Batrachedra amydraula, Meyr; -Dubas, Ommatissus binotatus var. Lybicus, De Bergevin -Raisin Moth, Cadra figulilella, Greg; -Arenipses sabella Haps; -Stem Borer, Jebusaea hammerschmidtii Reiche -Fruit Stalk Borer, Oryctes elegans; -Frond Borer, Phonopate frontalis, fahraeus; -Date Stone Beetle, Coccotrypes dactyliperda F.; -Apathe monachus Fabricius; -Inflorescences Pest, Carpophillus obseletus, Erichson; -Merchant Grain Beetle, Oryzaephilus mercator (Fauv); -Mealy Bugs, Muconellicoccus hirsutus Green; -Saw-Toothed Grain Beetle, Oryzaephilus surinamensis (L.); -Oriental Wasp, Vespa orientalis L.; -Yellow Wasp, Polistes hebroeus F.; -Spotted Yellow Wasp, Polistes gallicus L.; -Palm Bud Mite, Mackiella phoenicis K.; -Bettle Mite, Mycobatus sp; -Palm False Spider Mite, Tenuipalus eriophyides, Baker; -Leaflet False Spider Mite, Raoiella indica Hirst; -Other pests of stored dates: Tribolium castaneum, Tribolium confusum, Trigoderma granarium and Cryptolestes ferrugineus

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Appendix: 7

Appendix: 7-1: Mean weekly percentage mortality of adult females and immature stages of green pit scale insect from trees treated with soil applied insecticides, Elgaba Scheme, season 2003/4

134

Appendix: 7-2: Mean weekly percentage mortality of adult females of green pit scale insect from trees treated with soil applied insecticides, El Golid, 2004/2005.

River banK (L1) Actara 18g

Actara 15g 120 Actara 12g 100 Rinfidor 35ml

80 Rinfidor 25ml

60 Rinfidor 20ml

Comodor 35ml 40 Percentge mortality Percentge Comodor 25ml 20 Comodor 20ml 0 Confidor 35ml 0246812 weeks after application Untreated control

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Appendix: 7-3: Mean biweekly percentage mortality of immature stages of green pit scale insect from trees treated with soil applied insecticides, El Golid, 2004/2005.

At the bank of the Nile (L 1) Actara18g

120 Actara15g Actara12g 100 Rinfidor35ml

80 Rinfidor25ml Rinfidor 20ml 60 Comodor35ml

Perecentage mortality 40 Comodor25ml Comodor20ml 20 Confidor35ml 0 Untreated control 0246812

Weeks after application

Three km from the Nile (L 2)

120

Actara 18g 100

Rinfidor35ml 80

60 Comodor 35ml Percentage mortality 40 Confidor35ml

20 Untreated control

0 0246812 Weeks after application

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Appendix: 7-4: Mean biweekly percentage mortality of adult females and Immature stages of green pit scale insect from trees treated with trunk injected insecticides in Elgaba scheme season, 2003/2004.

Adult females

120 Actara10g.g

100 Actara8g.g

80 Actara6g g

60 Confidor 20ml

Percentage mortality 40 Confidor 15ml

20 Confidor 10ml

Untreated control 0 0246812

Weeks after application

Immature stages

120 Actara 10g.

100 Actara 8g. Actara 6g 80 Confidor 20ml 60 Confidor 15ml Percentage mortality 40 Confidor 10ml 20 Untreated control 0 0246812

Weeks after application

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Appendix: 7-5: Mean weekly percentage of adult females and immature tages of green pit scale from trees insect treated with trunk injected insecticides, El Golid, season 2004/2005. .

Adult females

120 Actara 10g Actara 8g 100 Actara 6g Rinfidor 20ml 80 Rinfidor 15ml Rinfidor 10ml 60 Comodor 20ml Comodor 15ml Percentage mortality Percentage 40 Comodor 10ml Confidor 20ml 20 Confidor 15ml Confidor 10ml 0 Untreated control 0246812

Weeks after application

Immature stages

Weeks after application

138

Appendix 8

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Appendix 8 (Cont.)

Faculty of Science- University of Jordon

Analysis of date samples Sample Specification Res. data Average Green Fruit Untreated date fruit (small) < 0.01 Sampling:12.5.93 < 0.01 < 0.01 (85 d) < 0.01 ppm Treated date fruits with < 0.01 Confidor 5 GR 2 months before < 0.01 < 0.01 < 0.01 ppm Yellow fruit Treated date fruits (Large) < 0.01 Sampling (26.6.93) treated with Confidor granules < 0.01 < 0.01 (130 d) (10.0 g / tree) < 0.01 ppm Untreated ripe date fruits (*) Ripe fruit Untreated ripe date fruits < 0.01 Sampling: < 0.01 < 0.01 20 Sep 93 < 0.01 ppm (192 d) Date fruit (ripe) treated with < 0.01 100 g Confidor 5GR/tree < 0.01 < 0.01 < 0.01 ppm

(*) No untreated sample was delivered for the yellow fruits The detection limit is 0.05 ppm taken as signal /noise =3 Trees treated with Confidor 5 GR at 10.0 g / tree on 16.2.93

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