ECOLOGICAL STUDIES ON LACE BUGS (: ) ON THEIR MAJOR HOST PLANTS IN KHARTOUM STATE

BY Abd alla Abdel rahim Satti

B.Sc. (Agric.) Hons., University of Gezira M.Sc. (Agric.), University of Khartoum

A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy

Supervisor Prof. El-Imam El-Khidir

Department of Crop Protection Faculty of Agriculture University of Khartoum

December – 2003

1 TABLE OF CONTENTS

Page ACKNOWLEDGEMENTS …………………………………….. iv ABSTRACT ……………………………………………………. v ARABIC ABSTRACT …………………………………………. Vi 1. INTRODUCTION …………………………………………… 1 2. REVIEW OF LITERATURE ……………………………….. 5 2.1. Lace bugs (= tinged bugs) ……………………………….. 5 2.1.1. Classification ………………………………………… 5 2.1.2. Description …………………………………………… 8 2.1.3. Life history and ecology ……………………………... 9 2.1.4. Distribution and damage ……………………………... 10 2.1.5. Natural enemies ……………………………………… 12 2.1.5.1. Parasites………………………………………….. 12 2.1.5.2. Predators………………………………………….. 12 2.1.6. General control measures ……………………………. 18 2.1.6.1. Cultural methods …………………………………. 18 2.1.6.2. Insecticidal control ………………………………. 19 2.2. Eggplant lace bug (= eggplant tingid bug) ………………. 19 2.2.1. ……………………………………………. 19 2.2.2. Description …………………………………………… 20 2.2.3. Life history and bionomics …………………………... 21 2.2.4. Ecology ………………………………………………. 22 2.2.5. Distribution …………………………………………... 23 2.2.6. Host plants …………………………………………… 23 2.2.7. Damage and economic importance ………………….. 24 2.2.8. Natural enemies …………………………………….. 25 2.2.9. Control ……………………………………………….. 25 2.3 "Adasi" lace bug ………………………………………….. 26 2.3.1. Taxonomy ……………………………………………. 26 2.3.2. Distribution …………………………………………... 26 2.3.3. Host plants …………………………………………… 27 2.4. Sunflower lace bug ………………………………………. 27 2.4.1. Taxonomy ……………………………………………. 27 2.4.2. Description …………………………………………… 27 2.4.3. Life history …………………………………………… 28 2.4.4. Ecology ………………………………………………. 28 2.4.5. Distribution …………………………………………... 29 2.4.6. Host plants …………………………………………… 29 2.4.7. Damage ………………………………………………. 30 2.4.8. Control ……………………………………………….. 30

2 3. MATERIALS AND METHODS ……………………………. 31 3.1. Field experiments ………………………………………… 31 3.1.1. Eggplant ……………………………………………… 31 3.1.2. Pigeon pea …………………………………………… 32 3.1.3. Sunflower …………………………………………….. 32 3.2. Field surveys ……………………………………………... 33 3.2.1. Lace bugs and their hosts plants ……………………... 33 3.2.2. Predators and their hosts plants ……………………… 33 3.3. Laboratory work …………………………………………. 34 3.3.1. Monitoring of lace bug parasites …………………….. 34 3.3.2. Morphological presentation of important lace bug ………………………………………………... 34 3.3.3. Durations of the pre-adult stages of important lace bug species on some of their major host plants .……... 35 4. RESULTS ……………………………………………………. 39 4.1. Encountered lace bugs and their host plants ……………... 39 4.2. General morphological and behavioural observations …… 65 4.3. Seasonality of lace bugs and their distribution within host plants ………………………………………………... 67 4.4. Damage inflicted by the different lace bug species ……… 92 4.5. Duration of the pre-adult stages of some important species on their major host plants ………………………... 97 4.6. Natural enemies of lace bugs and their seasonal abundance ………………………………………………... 103 5. DISCUSSION ………………………………………………... 137 REFERENCES……………………………………………… 151

3 ACKNOWLEDGEMENTS Firstly, praise and thanks be to Allah, Lord of the world, who gave me strength and ability to conclude my research work. Secondly, I am very grateful and deeply indebted to my supervisor, Prof. El Imam El Khidir, for his thorough knowledge that makes us love and enjoy the science of ecology, not merely of our , but of our , plants, peoples and planet too. Through continuous investigations and invaluable dialogues he offers, the research time has passed unfelt. Also, it is a pleasure to acknowledge that kind helps I have received from the staff members and technicians of the Department of Crop Protection, Faculty of Agriculture, University of Khartoum (U. of K.), throughout the study period. I appreciate the cooperation provided between the National Centre for Research (NCR), University of Sudan (U. of S.), particularly the Faculty of Agricultural Studies, and the Faculty of Agriculture, U. of K., which facilitated the performance of the field experiments at Shambat. Special thanks are due to Dr. Seifel Din M. Khair and the staff members of the Department of Crop Protection, U. of S., for their fruitful cooperation. Thanks are also due to Dr. Sami A. Hamid, for permitting using his valuable Canon Camera during the field surveys, and to Dr. Abdel Wahab Hassan, for providing sunflower seeds. Finally, I deeply acknowledged the fund executed to this study by the Ministry of Sc. and Tech., and the help rendered to me by the Environment and Natural Resources Research Institute (ENRRI), NCR. I am grateful in particular to Dr. Osman E. Nasr, Head of the Department of Biocontrol and Alternatives to Pesticides, ENRRI, for encouragement, and to my colleaques Seifel Din, Mogbil and Abdel Muniem for their helps in various ways. The real assistant of Mogbil A. El Nuari made the difficulties of surveys and recognition of some new insects in the field, more possible and fruitful. Thanks are lastly extended to Ikhlas Y., for patience in typing this thesis.

4 ABSTRACT Ecological studies on lace bugs (Hemiptera: Tingidae) were carried out during three consecutive years (2000 – 2002) in Khartoum State, where these pests were investigated in their natural habitats. The research work was executed through field experiments, extensive field surveys on cultivated and wild hosts plants, and was supported by some laboratory work. Species present in the area with new ones, together with their host plants were recorded. Some essential features of the detected lace bugs were drawn. The seasonality of important species, their distribution on host plants, and the characteristics of damage inflicted were closely followed under field conditions. The duration of immature stages were also studied in the laboratory. Moreover, natural enemies were evaluated in various habitats. A total of nine lace bug species and nineteen host plants were found, from which six pests and thirteen hosts were new records. Urentius spp. were never found infesting the same host plants together, as believed. These species revealed an increase in their population build up twice a year, both at the end of rainy and winter seasons. On the other hand, scrophicus Saunders and most of the newly encountered lace bugs peaked once, only during winter season. Some species with camouflaging habits were discussed. Different feeding patterns exhibited on leaves by the various lace bugs were explained. Various groups of general predators were found. Spiders (various species) were the dominant group associated with lace bugs during all seasons, followed by chrysopids and lastly, coccinellids. Prevalence of these predators on the bug host plants and other plants not attacked by the bugs were thoroughly discussed. Field management to preserve such natural enemies was thought essential.

5 ﺍﻟﺨﻼﺼﺔ

ﺃﺠﺭﻴﺕ ﺩﺭﺍﺴﺎﺕ ﺒﻴﺌﻴﺔ ﻋﻠﻰ ﺤﺸﺭﺍﺕ ﺒﻕ ﺍﻟﺘﻨﺠﺩ (Lace bugs) ﺍﻟﺘﻲ ﺘﺘﺒﻊ ﻟﻠﻌﺎﺌﻠﺔ Tingidae ﺘﺤﺕ ﺭﺘﺒﺔ ﻨﺼﻔﻴﺔ ﺍﻷﺠﻨﺤﺔ (Hemiptera) ﻋﻠﻰ ﻋﻭﺍﺌﻠﻬﺎ ﺍﻟﻤﺨﺘﻠﻔﺔ ﺒﻭﻻﻴﺔ ﺍﻟﺨﺭﻁﻭﻡ ﻓﻲ ﺍﻟﻔﺘﺭﺓ ﻤﻥ 2000 ﺇﻟﻰ 2002 ، ﻭﺫﻟﻙ ﻤﻥ ﺨﻼل ﺇﺠﺭﺍﺀ ﺍﻟﻌﺩﻴﺩ ﻤﻥ ﺍﻟﺘﺠﺎﺭﺏ ﺍﻟﺤﻘﻠﻴﺔ ﻭﺍﻟﻤﺴﻭﺤﺎﺕ ﺍﻟﻤﻴﺩﺍﻨﻴﺔ ﻋﻠﻰ ﺍﻟﻌﻭﺍﺌل ﺍﻟﻤﺨﺘﻠﻔﺔ ﺒﺎﻹﻀﺎﻓﺔ ﻟﺒﻌﺽ ﺍﻟﺘﺠﺎﺭﺏ ﺍﻟﻤﻌﻤﻠﻴﺔ. ﻫﺩﻓﺕ ﺍﻟﺩﺭﺍﺴﺔ ﺇﻟﻰ ﺍﻟﺘﻌﺭﻑ ﻋﻠﻰ ﺍﻷﻨﻭﺍﻉ ﺍﻟﻤﻭﺠﻭﺩﺓ ﻭﺒﻌﺽ ﻤﻼﻤﺢ ﺼﻔﺎﺘﻬﺎ ﻭﺴﻠﻭﻜﻴﺎﺘﻬﺎ ﻭﻋﻭﺍﺌﻠﻬﺎ ﺍﻟﻬﺎﻤﺔ. ﻫﺫﺍ ﺒﺎﻹﻀﺎﻓﺔ ﻟﺩﺭﺍﺴﺔ ﺍﻟﺘﻌﺩﺍﺩ ﺍﻟﻤﻭﺴﻤﻲ ﻟﻸﻨﻭﺍﻉ ﺍﻟﻬﺎﻤﺔ ﻭﺘﺤﺩﻴﺩ ﻜﻴﻔﻴﺔ ﺘﻭﺯﻴﻌﻬﺎ ﻋﻠﻰ ﺍﻟﻨﺒﺎﺕ ﻭﻤﻥ ﺜﻡ ﻁﺒﻴﻌﺔ ﺍﻟﻀﺭﺭ ﺍﻟﻨﺎﺠﻡ ﻋﻥ ﺍﻟﺘﻐﺫﻴﺔ. ﺍﺸﺘﻤﻠﺕ ﺍﻟﺩﺭﺍﺴﺔ ﺍﻟﻤﻌﻤﻠﻴﺔ ﻋﻠﻰ ﺘﺤﺩﻴﺩ ﻁﻭل ﻓﺘﺭﺓ ﺍﻷﻁﻭﺍﺭ ﻏﻴﺭ ﺍﻟﻜﺎﻤﻠﺔ ﻭﺫﻟﻙ ﺨﻼل ﻤﻭﺴﻤﻲ ﺍﻟﺨﺭﻴﻑ ﻭﺍﻟﺸﺘﺎﺀ. ﻤﻥ ﻨﺎﺤﻴﺔ ﺃﺨﺭﻯ ﺘﻀﻤﻨﺕ ﺍﻟﺩﺭﺍﺴﺎﺕ ﻭﺍﻟﻤﺴﻭﺤﺎﺕ ﺍﻟﺤﻘﻠﻴﺔ ﺍﻟﺘﻌﺭﻑ ﻋﻠﻰ ﺍﻷﻋﺩﺍﺀ ﺍﻟﺤﻴﻭﻴﺔ ﺍﻟﻤﺘﻭﺍﺠﺩﺓ (ﺨﺎﺼﺔ ﺍﻟﻤﻔﺘﺭﺴﺎﺕ) ﻭﻤﺴﺘﻭﻴﺎﺕ ﺘﻌﺩﺍﺩﻫﺎ ﺍﻟﻤﻭﺴﻤﻲ ﻭﺘﻭﺯﻴﻌﻬﺎ ﻋﻠﻰ ﻤﺨﺘﻠﻑ ﺍﻟﻌﻭﺍﺌل.

ﻟﻘﺩ ﺘﻡ ﺍﻟﺘﻌﺭﻑ ﻋﻠﻲ ﻋﺩﺩ ﺘﺴﻌﺔ ﺃﻨﻭﺍﻉ ﺤﺸﺭﻴﺔ ﻤﻥ ﺒﻕ ﺍﻟﺘﻨﺠﺩ ﻭﺘﺴﻌﺔ ﻋﺸﺭ ﻨ ﻭ ﻋ ﺎﹰ ﻤﻥ ﺍﻟﻌﻭﺍﺌل ﺍﻟﻨﺒﺎﺘﻴﺔ ، ﺒﻴﻨﻬﺎ ﺴﺘﺔ ﺃﻨﻭﺍﻉ ﻤﻥ ﺍﻟﺤﺸﺭﺍﺕ ﻭﺜﻼﺜﺔ ﻋﺸﺭ ﻨ ﻭ ﻋ ﺎﹰ ﻤﻥ ﺍﻟﻌﻭﺍﺌل ﺘﺴﺠل ﻷﻭل ﻤﺭﺓ. ﺘﺅﻜﺩ ﺍﻟﻨﺘﺎﺌﺞ ﻋﻠﻲ ﻭﺠﻭﺩ ﻋﻭﺍﺌل ﻤﻨﻔﺼﻠﺔ ﻟﻜل ﻤﻥ ﺒﻕ ﺍﻟﺒﺎﺫﻨﺠﺎﻥ ( Urentius hystricellus) ﻭﺒﻕ ﺍﻟﻌﺩﺴـﻲ (U. euonymus). ﺃﻭﻀـﺢ ﺍﻟﺘﻌـﺩﺍﺩ ﺍﻟﻤﻭﺴﻤﻲ ﺒﺄﻥ ﻤﺠﺎﻤﻴﻊ ﻫﺫﻩ ﺍﻵﻓﺎﺕ (.Urentius spp) ﺘﺯﺩﺍﺩ ﺒﺩﺭﺠﺔ ﻜﺒﻴﺭﺓ ﺨﻼل ﻓﺘﺭﺘﻴﻥ ﻓﻲ ﺍﻟﻌﺎﻡ، ﻋﻨﺩ ﻨﻬﺎﻴﺔ ﻜل ﻤﻥ ﻤﻭﺴﻤﻲ ﺍﻟﺨﺭﻴﻑ ﻭﺍﻟﺸﺘﺎﺀ. ﺩﺭﺠﺔ ﺍﻹﺼﺎﺒﺔ ﺒﺘﻨﺠﺩ ﺯﻫﺭﺓ ﺍﻟﺸﻤﺱ (Galeatus scrophicus) ﻭﻤﻌﻅﻡ ﺍﻷﻨﻭﺍﻉ ﺍﻷﺨﺭﻯ ﺘﺯﺩﺍﺩ ﺒﺼﻭﺭﺓ ﻭﺍﻀﺤﺔ ﺨﻼل ﻤﻭﺴﻡ ﺍﻟﺸﺘﺎﺀ. ﻟﻘﺩ ﺍﺸﺘﻤﻠﺕ ﺍﻟﻨﺘﺎﺌﺞ ﺃﻴﻀﺎ ﻋﻠﻲ ﻤﻨﺎﻗﺸﺔ ﺒﻌﺽ ﺍﻟﻤﻼﺤﻅﺎﺕ ﺍﻟﺴﻠﻭﻜﻴﺔ ﻟﺒﻌﺽ ﺃﻨﻭﺍﻉ ﺍﻟﺘﻨﺠﺩ ﻤﺜل ﺍﻟﻤﻤﺎﺘﻨﺔ (ﺍﻟﺘﺨﻔﻲ) ﺒﻐﺭﺽ ﺍﻟﺤﻤﺎﻴﺔ ﻤﻥ ﺃﻋﺩﺍﺌﻬﺎ ﺍﻟﻁﺒﻴﻌﻴﺔ. ﻭﺃﺒﺎﻨﺕ ﺍﻟﺩﺭﺍﺴﺔ ﻭﺠﻭﺩ ﺍﺨﺘﻼﻓﺎﺕ ﻫﺎﻤﺔ ﻓﻲ ﻜﻴﻔﻴﺔ ﻭﻤﻭﻀﻊ ﺃﺤﺩﺍﺙ ﺍﻟﻀﺭﺭ ﺒﺄﻭﺭﺍﻕ ﺍﻟﻌﺎﺌل ﺘﻡ ﺘﺩﻭﻴﻨﻬﺎ ﻟﻤﻌﻅﻡ ﺍﻷﻨﻭﺍﻉ. ﻜﺫﻟﻙ ﺃﻅﻬﺭﺕ ﺩﺭﺍﺴﺔ ﺍﻷﻋﺩﺍﺀ ﺍﻟﺤﻴﻭﻴﺔ ﻭﺠﻭﺩ ﺃﻋﺩﺍﺩ ﻜﺒﻴﺭﺓ ﻤﻥ ﺍﻟﻤﻔﺘﺭﺴﺎﺕ ﺍﻟﻌﺎﻤﺔ ﺍﻟﺘﻲ ﺘﺘﻐﺫﻯ ﻋﻠﻲ ﺍﻟﺘﻨﺠﺩ ﻭﻏﻴﺭﻫﺎ ﻤﻥ ﺍﻟﺤﺸﺭﺍﺕ. ﻤﻥ ﺃﻫﻡ ﻤﺠﻤﻭﻋﺎﺕ ﻫﺫﻩ ﺍﻟﻤﻔﺘﺭﺴﺎﺕ ﺒﺎﻟﻨﺴﺒﺔ ﻟﺒﻕ ﺍﻟﺘﻨﺠﺩ، ﻤﺠﻤﻭﻋﺔ ﺍﻟﻌﻨﺎﻜﺏ – Spiders (ﺃﻨﻭﺍﻉ ﻤﺨﺘﻠﻔﺔ)، ﺘﻠﻴﻬﺎ ﻤﺠﻤﻭﻋﺔ ﺃﺴﺩ ﺍﻟﻤﻥ (chrysopids)، ﻭﺃ ﺨ ﻴ ﺭ ﺍﹰ ﻤﺠﻤﻭﻋﺔ ﺃﺒﻭ ﺍﻟﻌﻴﺩ (coccinellids)، ﻭﺍﻟﺘﻲ ﺘﻡ ﻓﺤﺼﻬﺎ ﻓ ﺤ ﺼ ﺎﹰ ﻤﺴﺘﻔﻴﻀﺎ ﻤﻥ ﺤﻴﺙ ﺘﻭﺯﻴﻌﻬﺎ ﻋﻠﻲ ﺍﻟﻨﺒﺎﺘﺎﺕ ﺍﻟﻌﺎﺌﻠﺔ ﻟﻠﺘﻨﺠﺩ ﻭﻏﻴﺭﻫﺎ ﻤﻥ ﺍﻟﻨﺒﺎﺘﺎﺕ ﺍﻻﺨﺭﻱ ﺒﺎﻟﺤﻘل ﻟﻤﻌﺭﻓﺔ ﺃﻭﺴﻊ ﻻﺩﺍﺀ ﺩﻭﺭﻫﺎ ﻓﻲ ﺍﻟﺘﻭﺍﺯﻥ ﺍﻟﺒﻴﺌﻲ.

6 1. INTRODUCTION

The Sudan is considered as one of the twelve largest countries in the world, with its area account for 967,500 square miles, lies wholly within the tropics, between latitudes 22º and 3º North and longitudes 38º and 22º East. Topographically, the country is more or less a uniform plains, except for few altitudes such as Marra and Nuba Mountains in the west and the Red Sea Hills in the east, which have limited effect on the climate of these areas. Most of this large area is a fertile land of potential agricultural value. There is a sudd region in the south where extensive swamps spreading over a large area , and the River Nile with its tributaries traversed the country along 1,300 miles from the southern to the northern borders (Ireland, 1948, and Rath, 1954). The climatic features of the Sudan were concisely dictated by Ireland (1948) since the colonial period. Except for the maritime characteristics shown in the eastern side of the Red Sea Hills, Sudan can be divided into two distinguishable climatic regions. North of about latitude 19º N. is a desert region where dry northerly winds (hot in summer and cold in winter) prevailing throughout the year, while south of this line is a typical tropical continental climate dominated by the annual movement of the Intertropical Front between the dry northerlies and the moist southerlies. Considerably lower temperatures and higher air humidity are the characteristics of the southern part of the country as opposite to that of the northern part. Convectional rain is associated with the southerly winds in a zone extending about 500 miles south from the intertropical boundary. The rainfall increases gradually from an average of about 75 mm in latitude 19ºN. to well over 1250 mm in the extreme south. Such variability in climatic conditions from the north to the south have shown its greatest manifestation in biological diversity (flora and

7 fauna) of this region. Therefore, the type and density of the vegetation present varies from practically complete desert in the north through the savanna in the centre to the forest and tropical swamps in the south. The Khartoum State lies within the semi-desert region of the central Sudan, between the latitudes 15º 15َ - 16ºN. and longitudes 32º 32º 45َ E., occupies an area of about 1,020 square miles. As described 15َ- above, this region witnesses a mild winter season (November – March) dominated by the dry northerly winds, and a hot summer period (April – June), followed by the rainy autumn season (July – October) dominated by the hot moist southerly winds. Dust-storms are common during the autumn months just before and during the rains, which can reach a height of 2,400m and have a frontage between 80 – 160km. The mean maximum and minimum temperatures at Khartoum were recorded to be as 41.7ºC. and 15.6ºC, respectively. It was found that May and June are the hottest months of the year, while January is the coldest month. The mean annual rainfall was 163 mm and, the mean relative humidity at 0800 and 1400 hours were 38% and 21%, respectively. Accordingly, August is the most humid month in the year, and corresponds to the peak of rainfall. Many types of natural vegetations (shrubs and trees) are grown widely in the State, especially along the two banks of the Nile (White, Blue and River Nile), sides of irrigation canals, drainage and depressions. The whole area turns green during the rainy season as numerous herbaceous weeds germinate annually, of which more than 320 species were identified (Abd alla, 1968, and Bebawi and Neugebohrn, 1991). The State is considered as one of the important agricultural areas where orchards, forage and vegetable crops are cultivated extensively to cover some needs of the fast growing population in the capital. Some of these

8 vegetables such as muskmelon and eggplant are produced by certain companies for export. Therefore, such diversity in natural flora coupled with the extensive farming system, had provided suitable habitat which enriched the biotic fauna in the area, especially those of direct agricultural concern like insects. Different species of pests were reported to cause an economic damage on various field and horticultural crops (Venkatraman and El Khidir, 1967; Schmutterer, 1969; Guddoura, 1977; Guddoura et al., 1984). The population of these pests were found to be affected by different biotic (e.g. natural enemies and host plants) as well as abiotic (e.g. weather conditions) factors. Although, very meagre research is available in this field, few studies carried out in Khartoum, showed a clear impact of some ecological and climatic conditions on the behaviour and population abundance of some major pests (e.g. El Khidir, 1960). Numerous species of entomophagous insects especially predators and parasites with reference to their role as important suppressive factors for many insect pests were reported by some scientists (Bashir, 1968, and Satti et al., 1998). Among various insect pests, the lace bugs (Hemiptera) were recorded as one of the important economic pests in Khartoum and other parts of the Sudan. Although, lace bugs are very numerous worldwide, only three species were known so far in this country. The most important one is the eggplant lace bug, Urentius hystricellus Richter. The other species are Urentius euonymus Distant, attacking pigeon pea (Cajanus cajan (L.) Mill sp.) and other wild host plants, and Galeatus scrophicus Saunders, a pest of sunflower (Helianthus annus L.). Few studies were conducted concerning U. hystricellus, but nothing was done on the other two pests. There is a shortage of good scientific research on different aspects of the lace bugs in general. There seems to be, for instance, some

9 confusion as with regard to the host range between U. hystricellus and U. euonymus. Information on biology, ecology and control is lacking especially on U. euonymus and G. scrophicus. Therefore, an attempt was put forward in this study to fill some research gaps on lace bugs in general with special emphasis on the above mentioned three species, as summarized in the following objectives: • To verify the host plants of U. hystricellus and U. euonymus and, to distinguish between the two species depending on some morphological characters. • Survey and monitoring of the different species of lace bugs and their damage characteristics and host range in Khartoum area. • Seasonality of the three recorded lace bug species and their main natural enemies (predators) on some major hosts among cultivated and wild plants. • Seasonality of the above predators on other selected plants not serving as hosts for the lace bugs. • Distribution of adult and nymphal stages of the lace bugs and their predators between the upper and the lower surfaces of plant leaves. • Comparative studies on the duration of life cycle of the immature stages of some important lace bugs on cultivated and wild host plants during autumn and winter seasons.

10 2. REVIEW OF LITERATURE

2.1. Lace bugs (= tingid bugs)

2.1.1. Classification Class : Insecta Order : Hemiptera Suborder : Geocorizae Family : Tingidae Laporte = Tingididae Fieber = Tingitidae Stal Subfamilies (three) (1) Vianaidinae Kormilev (2) Stal (3) Laporte The family Tingidae includes terrestrial bugs (gymnocerata in part) under suborder, Geocorizae, one of the three suborders belonging to the order Hemiptera. Such three suborders are separated principally by antennal structure and habits (Borror et al., 1976). As catalogued by Drake and Ruhoff (1965), the family consists of 1820 species (include both living and extinct forms) arranged in three subfamilies and 236 genera. However, according to Hill (1983), only about 700 species of lace bugs were reported. Consequently, the classification of tribes, genera and species is based mainly upon the lacy outgrowths, especially the formations of the pronotum and the elytra, and to some extent upon the features of the buccal, sternal and hypocostal laminae. The lace work of the forewings and upper surface in adults is peculiar to each species of lace bugs (Drake and Ruhoff, 1965). Examples of some common species of lace bugs in a world wide level are summarized in the following list:

11

Description The members of the family Tingidae are very characteristic and easily recognized, especially adults, by their densely reticulated body surface (upper side) and hemelytra, hence, the name lace bugs. Sometimes, such insects are also called tingid bugs (Pollard, 1955, and Schmutterer, 1969). According to Drake and Ruhoff (1965), the lace work is original and specific to each species, and only adults of the same species that are dressed identical. Lace bugs are relatively small insects (5 – 6 mm in length), some are nearly miniature in size. They exhibit a great diversity of forms, varies from long and very slender to extremely wide body form. The pronotum has a triangular process that extends backward over the scutellum, with some species owing an additional hoodlike pattern of the pronotum extending forward over the head. Moreover, the head, lateral expansions of the thorax and wings usually show a pattern of elevated ridges and sunken membranous oval areas (Drake and Ruhoff, 1965, and Borror and White, 1970). Most adults of the lace bugs are more or less grayish, brownish or whitish and somewhat rectangular in outline. There are scarcely any differences in the outward appearances (e.g. size, colour and markings) between the sexes. Members of most species move rather slowly when disturbed, but adults of some species tend to drop from the plant parts that are touched. On the other hand, nymphs are usually spiny, somewhat dark brown or blackish in colour, and oval in outline. However, lace bugs have antennae and beak four segmented, tarsi one or two segmented, and ocelli are lacking (Drake and Ruhoff, 1965; Borror and White, 1970; Borror et al., 1976; Hill, 1983, and Shetlar, 1991).

79 2.1.3. Life history and ecology The female lace bug generally lays its eggs on the undersides of the leaves, thrust deeply into the plant tissues almost up to the operculum, and coated with a dark brownish adhesive material that soon hardens and forms a protective coating. The eggs are usually inserted in new leaves along the midvein or near it. Upon hatching, nymphs generally feed in groups on lower leaf surfaces. is gradual, and five nymphal instars are mainly present. However, in very few species, four (e.g. rhododendri) or six nymphal stages are present (Shetlar, 1991; Hanson and Walker, 1999, and Anon., 2002). According to the lace bug species and the prevailing weather conditions in temperate zones, the life cycle requires four to seven weeks, and overwintering stage was recorded either in the imaginal (e.g. ciliata) or egg (e.g. ) stage. Overwintering adults always occur among lace bugs groups that attack deciduous plants, where they hibernate under the plant bark or near the plant in leaf litter. On the other hand, lace bugs overwintering in the egg stage were found among species attacking evergreens, where they attached their eggs to the green leaves. Consequently, most species in such region were active during spring and summer periods. Therefore, they are generally uni-or bi-voltene, though, three to five generations a year were reported in some cases (Shetlar, 1991). However, the duration of the life cycle takes less time in the tropics, and no resting stage in these areas was reported in the literature, except in very few cases (e.g. Singh and Mann, 1986). Most species of lace bugs prefer sunny habitats, and when disturbed, they exhibit a peculiar bouncing movement. Natural control factors, such as natural enemies, usually keep the population of these pests at low levels, but local population flare-ups do occur

80 occasionally (Drees and John, 1999; Hanson and Walker, 1999, and Anon., 2002).

2.1.4. Distribution and damage Lace bugs are distributed allover the world in the torrid and temperate zones. They are found in all continents and many islands, and several species could be detected in one place. For instance, a list of 80 lace bug species found in Turkey was given by Onder and Lodos (1983), and about 160 species have been described in North America (Hoover, 1992). In the Sudan, the actual numbers of lace bug species existed were unknown. However, according to Drake and Ruhoff (1965) seven species were reported in this country. These were; Urentius hystricellus Richter (on eggplant); U. euonymus Distant (on pigeon pea); Galeatus scrophicus Saunders (on sunflower); Cysteochila tarda Drake (on "kitir"); absimilis Drake (unknown hosts); Lasiacantha horvathi Drake (unknown hosts), and Kapiriella polita (Drake) (on millet). In addition to these species two lace bug samples were found preserved in the Insects Collection of the Agricultural Research Corporation, under the names Monanthia sp. and Lambella sp. reported on pigeon pea and "Khash–Khash", respectively. Except for few studies on Urentius hystricellus and Galeatus scrophicus, no information is found as with regard to the all above mentioned species. Lace bugs are purely plant feeding insects. Both adults and nymphs obtain food by piercing the epidermis of the leaf blades of living plants and sucking the sap by means of the protrusible and retractile stylets operating from a freely movable haustellum. As stated by Hill (1983), all plant feeders among have toxic saliva which when injected into a plant , causes necrosis and death of shoots and branches. Therefore, the feeding habit of the lace bugs usually causes a yellow spotting of the

81 leaf, which becomes entirely brown and fall off. This results in extensive defoliation when infestation is high. Cast skins and dark brown spots of excrement are mainly deposited on the undersides of leaves. Healthier trees, in some instances, were observed to withstand damage and showed lower incidence of lace bugs compared with old, neglected or badly stressed trees as a result of water shortage and lack of nutrients in certain marginal areas. However, healthier trees and shrubs can also be damaged if heavy feeding occurs over several consecutive years. Newly transplanted seedlings can also be checked if earlier infestation occurs. Some species of lace bugs cause extensive leaf curl on the foliage of their host plants, while others are known as gall-forming insects. Nymphs of lace bugs are also reported to produce honeydew, which covers the leaves and becomes blackened by the development of sooty mold fungi (Gouveia and Ohlendroff, 2002). Some authors reported that, the brown necrotic areas on the leaves caused by the lace bugs are due to the injuries of bug feedings which provided infection court for some pathogens e.g. anthracnose fungus, Colletotrichum sp. and powdery mildew, Oidium sp. (Mead, 1998). Moreover, some lace bug species were also accused of being vectors of certain viral diseases (Nagaraj and Menon, 1956; Shanta et al., 1960, and Mathen, 1960 – as quoted by Drake and Ruhoff, 1965). Lace bugs are highly host specific, feeding primarily on one plant species and in some cases on a few closely related species. However, serious losses are effected by the lace bugs on many cultivated and wild plants, among field and horticultural crops, ornamentals, natural trees, shrubs and herbaceous plants or weeds. Therefore, some species of lace bugs have been exploited as biocontrol agents, such as scrupulosa Stal which was used for controlling the noxious Lantana plant

82 in different areas (Drake and Ruhoff, 1965; Borror and White, 1970; Borror et al., 1976, and Hill, 1983).

2.1.5. Natural enemies Several natural enemies (parasites and predators) were reported elsewhere, which help keep lace bugs in check. However, good research data on these enemies and their actual impact in controlling lace bug species are rather scarce. 2.1.5.1. Parasites A number of hymenopterous and dipterous insects are known as egg – or nymphal-parasites on several species of lace bugs world wide (Anon., 2002). In India, for instance, about 23 species of Tingidae in 20 genera were found parasitized by numerous species of egg parasitoids including e.g. trichogrammatids, Lathromeromyia spp. and Epoligosita sp., and the mymarids, Parallelaptera (=Erythmelus) spp. (Mani, 1972, and Livingstone and Yacoob, 1986). 2.1.5.2. Predators The different predators reported preying on various species of lace bugs are all known as general predators feeding, besides lace bugs, on several insect pests found in the field such as , , thrips, jassids, mealy bugs, lepidopterous eggs and larvae, scale insects and many others. predators include numerous species belonging mainly to the two classes, Insecta and Arachnida. They are found distributed allover the world in different habitats and at variable levels. According to Witcomb and Bell (1964) (quoted by Herrera, 1992) about 600 species of predatory were recorded only from a cotton field in Arkansas, U.S.A. Therefore, such predators generally play an important role in regulating the population levels of various insect pests under field conditions.

83 However, the dependence on synthetic organic chemicals in controlling insect pests, since the World War Π, had killed the natural enemies, tremendously reducing their numbers and levels and, hence, the natural balance of the agro-ecosystem has been disturbed. Therefore, compared with 140 predaceous species (in 26 families) recorded earlier before extensive usage of pesticides on cotton in the Sudan Gezira, only about 30 species representing 17 families could be found nowadays (Herrera, 1986b). In spite of that, it was concluded by some authors that the existing indigenous beneficial fauna in the Sudan, can play a major role in pest control, whenever pesticides are used judiciously (Beije and Ahmed, 1997). However, the major groups of these predators, especially those connected with the lace bugs, are summarized below: Lace wing larvae The green lace wing, Chrysoperla spp. (: Chrysopidae) were considered as one of the important groups of general predators distributed widely almost in all countries around Europe, America, Africa and Asia. In the Sudan Chrysoperla (= Chrysopa) pudica (C. carnea Steph.) and C. zastrowi (C. vulgaris Sch.) are the major species of lace wings prevailing in different parts of the country. They were recorded in most agricultural schemes in Gezira, Blue Nile, Rahad, New Halfa, Gash and Toker Deltas, as one of five dominant predatory groups (besides coccinellids, syrphids, predatory bugs and spiders) of insect pests of cotton, wheat, forage and horticultural crops. These predators were also found preying on pests of forage and vegetable crops in Khartoum State, as well as on date palm scales in northern Sudan. However, lace wing larvae were also reported as important predators of lace bugs in other countries (Shetlar, 1991; Kyhl and Hahn, 1999; Anon., 2002, and Gouveia and Ohlendorf, 2002). Since detailed data are lacking in this aspect, it is worthy to state that lace wing larvae were found to eat as

84 many as 50 eggs of the African bollworm or 15.4 cotton aphids per day. Moreover, the importance of Chrysoperla spp. came from the fact that they are found in the field throughout the year, but most abundant during winter season (October – February) in all surveyed areas (Bashir, 1968; El Magid, 1977; Herrera, 1992; Abdalla and Beije, 1997; Beije and Ahmed, 1997; Beije and G. Elanbia, 1997; Dabrowski et al., 1997; Guddoura, 1997, and Satti et al., 1998).

Ladybird beetles Entomophagous ladybird beetles (Coleoptera: ) are important group of general predators which found distributed in most countries, both in temperate and tropical areas. As numerous as 4000 coccinellid species were recorded earlier (Hagen, 1962) in a world wide level. However, in only one district in Algeria during the last decade, about 41 species of predatory coccinellids were surveyed (Saharaoui, 1994). The most important genera of Coccinellidae in biological control may include: Adalia (=Coccinella), Adonia (= Hippodamia), Brumus, Callineda, Cheilomenes (= Cydonia), Chilocorus, Coelophora, Coleomegilla, Cycloneda, Halyzia, Hyperaspis, Micraspis, Naemia, Paranaemia, Platynaspis, Propylaea, Pullus (= Scymnus) and Xanthadalia (Hagen, 1962). In the Sudan, the following species constitute the important coccinellids recorded in different regions mainly in northern, central and eastern parts of the country, as studied by: Bashir (1968); Herrera (1992); Abdalla and Beije (1997); Beije and Ahmed (1997); Satti et al., (1998), and Kuol (2003): - Cheilomenes (= Cydonia) propinqua vicina Muls. - Chilocorus distigma - Coccinella rufescence Muls. - Coccinella undecimpunctata L.

85 - Exochomus spp. - Hippodomia (= Adonia) variegata (Goeze) - Hyperaspis spp. - Micraspis striata - Scymnus spp. (e.g. S. levaillanti, S. marginallis Rossi and S. trepidulus) - Xanthadalia rufescens

The coccinellid insects as generalized predators were also found to prey on the same preys mentioned for the lace wing larvae. Nevertheless, coccinellids were known to prefer aphids than other insects. In addition, some coccinellids, such as Coccinella septempunctata L. and Hippodamia variegata (Goeze), were observed feeding on pollen grains of different crops (Sadeghi and Esmailli, 1992; Abdalla and Beije, 1997; Beije and Ahmed, 1997; Dabrowski et al., 1997, and Guddoura, 1997). However, feeding of some coccinellid species on lace bugs has been shown in some literature (Kyhl and Hahn, 1999). In some tropical countries including Sudan, certain coccinellid predators may be encountered in the field all the year round, but most activity and breeding occur during winter seasons (Bashir, 1968; Beije and Ahmed, 1997; Satti et al., 1998, and Kuol, 2003). Contrary, in temperate zone greater activity and reproduction take place in spring time, whereas hibernation occurs during winter period, but this is generally preceded in most regions by migration to mountains or other sheltered places (Hagen, 1962, and Sadeghi and Esmaili, 1992). Thrips Incidence of predation on lace bugs by certain species of thrips (Thysanoptera) was detected in some places over the world. For instance, Frankliniella vespiformis (Crawford) is a thrips species known as one of

86 the important predators of the avocado lace bug, perseae (Heidemann) (Abud Antun, 1991). Assassin bugs (Hemiptera: ) These predators were reported by: Shetlar, 1991; Anon., 2002, and Gouveia and Ohlendorf, 2002.

Spiders Spiders are members of the phylum Arthropoda, under the class Arachnida and order Araneida. With reference to their numbers, diversity of species and habitats, spiders came next in order following insects. They are general predators, but depend principally on insects for feeding. Several species of spiders belonging to several families (e.g. Araneidae, Clubionidae, Gnaphosidae, Lycosidae, Oxyopodidae, Pholcidae, Salticidae, and Thomisidae), found in different regions of the world, were considered key predators of important agricultural insect pests. Some authors suggested that spiders and other arachnids may have tremendous ecological importance and considered key factors in predator-prey dynamics. On the other hand, under certain circumstances spiders could also be considered harmfull. In America, e.g. Peucetia viridans (Hentz.) (Araneae: Oxyopidae) was found to feed on beneficial insects such as honey bees, syrphid pollinators and vespid predators and tachinid parasites of crop pests (Gurdip et al., 1976; Weems and Whitcomb, 1977; Riechort et al., 1985 [in Herrera, 1992], and Faragalla and Taher, 1988). Spiders have received less attention in research both in national and international levels, especially with regard to their real contribution in pests control. However, available information showed numerous species of potent concern, among which the crab spiders (Thomisidae) and others were known as important predators of lace bugs (Anon., 2002, and Gouveia and Ohlendorf, 2002). In Peru, as much as 52 species of spiders

87 in 17 families were reported by Aguilar (1977) (in Herrera, 1992). The role of spiders as regulatory factor of cotton insect pests has already been settled (Delucchi, 1975, and Sterling, 1983 – as quoted by Herrera, 1992). Out of 16 key predators of cotton bollworms and budworms in America, half of them were spiders which fed on all stages of the pest (Sterling, 1983 – as quoted by Herrera, 1992). In India more than thirteen species of spiders belonging to 7 families (e.g Araneus sp., Cheiracanthium spp., Clubiona sp., Heteropoda sp., Lycosa spp., Marpissa sp., Oxyopes spp., Phidippus sp., Thomisus sp. … etc) were found as important predators of larvae of Chilo partellus (Swinh.) on maize fields (Balraj et al., 1975, and Gurdip et al., 1976). Faragalla and Taher (1988) surveyed true spiders (suborder: Araneomorphae) in Saudi Arabia, as the first sole study on this topic in the area. Accordingly, the major groups include: the primitive line and sheet weavers (e.g. Pholcidae and Scytodidae), the combed- footed spiders (Theridiidae), the orb weavers (e.g. Argiopidae = Araneidae), and the hunting – (e.g. Lycosidae), jumping – (Salticidae), crab- (Philodromidae and Thomisidae), running – (e.g. Gnaphosidae and Zodariidae) and funnel – web – (e.g. Agelenidae and Cithaeronidae) spiders. However, some few studies in Sudan referred to spiders in the agro-ecosystems, though, clear identification of the species and assessment of their role in pests control are still in the dark. In central Sudan spiders were reported as one of the very common predators, both in vegetables and rotational crops. About 10 species were dictated by Herrera (1986b), who mentioned that most spider families considered as important predators of bollworms were found in Sudan. Spiders, mainly Salticidae, were therefore considered as one of the dominant beneficials in Sudanese cotton, in Gezira, Blue Nile and Gash Delta, preying on bollworms, jassids and whiteflies (Beije and Ahmed, 1997, and Beije and

88 G. Elanbia, 1997). Munir (1987, 1990) (as quoted by Beije and Ahmed, 1997) stated that the only natural enemies of jassids on cotton plants seemed to be spiders (especially Oxyopes sp.). It was also reported that spiders (often crab spiders) together with lace wing larvae were the most important factor for preventing or slowing down the build-up of aphids, Schizaphis sp., on wheat crop (Abd alla and Beije, 1997, and Dabrowski et al., 1997). Moreover, predators of vegetable pests complex of tomato, okra, egg plant and cucurbits in most areas (e.g Khartoum, Gezira and Blue Nile) were found to include spiders (mostly Salticidae) as one of the dominant groups encountered in the field (Herrera, 1986 a ; Beije and G. Elanbia, 1997, and Satti et al., 1998). The predation of spiders on lace bug species was also documented in Sudan (El Amin, 1998). Predaceous mites (Acarina) These were reported by several authors {Shetlar, 1991; Anon., 2002, and Gouveia and Ohlendorf, 2002).

2.1.6. General control measures 2.1.6.1. Cultural methods As reviewed by Schmutterer (1969); Salih (1991), and Kyhl and Hahn (1999) the main cultural practices in reducing lace bugs infestation on intended crops could be summarized in the following points: • Keep trees in good health with adequate fertilizer and water. • The nymphs on small plants can be managed by using a high- pressure water spray from a garden hose directed at the undersides of the leaves. • Removal of alternative host plants and crop residues between planting seasons. • Pruning of damaged foliage especially in trees. • Use of resistant varieties.

89

2.1.6.2. Insecticidal control Natural insecticides It was proved that some natural preparations such as neem extracts, insecticidal soaps (e.g. safer), horticultural oil and pyrethrins are effective products against lace bugs. These products were found to be safe environmentally and exerted low hazards to beneficial insects (Satti and Nasr, 1999, 2000; Anon., 2002, and Gouveia and Ohlendorf, 2002). Synthetic insecticides Several conventional insecticides are used which should be directed so that the underside of foliage is thoroughly covered. Such insecticides were generally recommended according to regulations in different localities, but chemicals commonly used in different areas were reported by Gouveia and Ohlendorf (2002) to include; systemic insecticides, e.g acephate (Orthene), carbamates, e.g. carbaryl (Sevin), organophosphates, e.g. malathion (Cythion) and, pyrethroids.

2.2. Eggplant lace bug (= eggplant tingid bug) 2.2.1. Taxonomy The pest was classified under the family Tingidae according to: Pollard, 1955; Drake and Ruhoff, 1965; Schmutterer, 1969, and Rasool et al., 1986. Scientific name : Urentius hystricellus Richter Synonyms : Urentius aegyptiacus Bergevin : Urentius echinus Distant : Urentius olivaceus Distant : Urentius sentis Distant : hystricellus Richter : Ayrerus hystricellus: Distant

90 Subfamily : Tinginae Laporte Family : Tingidae Laporte Order : Hemiptera 2.2.2. Description Adult: Oval to elongate, about 2.5 – 3 mm long and 1.5 mm broad. Legs light brown to brown. Ventral side of pronotum, scutellum and forewings reticulated, straw, brown or pale yellowish – green in colour, and with many spines especially on the anterior margins of the hemelytra and on the sides of pronotum. Compound eyes are prominent and reddish brown in colour. Antennae, yellowish – brown, have four segments with the third segment being rather long and the fourth one enlarged (clavate). They are as long as the thorax. Adults of the eggplant lace bug are very slow moving and seldom take to the wing (Schmutterer, 1969; Guddoura, 1977, and Salih, 1991). : Oval in shape and greenish yellow in colour. It is similar in appearance to the adult, but smaller in size and lacking dorsal reticulation and fully developed wings. The antennae had three segments in the first instar and four in the remaining instars. Wing pads became visible from the 3rd-instar and onwards. Numerous brown to blackish spines and brown spots are present on the dorsal surface of thorax and abdomen. The nymphs are sluggish bugs and the male nymph is smaller in size than the female (Schmutterer, 1969; Salih, 1991, and Singh and Mann, 1995). Egg: Oval in shape, curved slightly and has a chorionic operculum. It has a white or dull-yellow colour at first, which turns dark before hatching (Salih, 1991).

91 2.2.3. Life history and bionomics The eggs are embedded singly or in groups, by the females, in the plant tissues generally on the underside of leaves. The eggs measured on the average 0.462 ± 0.23 mm in length and 0.177 ± 0.015 mm in width, as shown by Singh and Mann (1995) in India, while they measured 0.73 ± 0.006 mm in length and 0.52 ± 0.007 mm in width, as studied by Salih (1991) in Sudan. The newly hatched nymphs are about 0.75 mm long. They feed in clusters usually near the midrib or other prominent veins, and moult five times before giving adults. The cast skins and black dots of excreta are found covering the lower surfaces of leaves (Pollard, 1955, and Schmutterer, 1969). The male bug is smaller than the female. In India, the average sizes of adults were 2.339 ± 0.079 and 2.400 ± 0.082 mm in length and 0.854 ± 0.050 and 0.875 ± 0.044 mm in width, for males and females, respectively (Singh and Mann, 1995). However, in the Sudan the average length of the males is 2.275 ± 0.10 mm and that of the females is 3.090 ± 0.06 mm (Salih, 1991). According to Tigvattn (1990) the duration of the egg and nymphal stages of U. hystricellus in the laboratory in Thailand, was averaged 11.57 and 12.27 days, respectively. However, Pollard (1955) and Schmutterer (1969) reported that the total duration of the life cycle from egg laying to emergence of adult is completed within 10 – 12 days. Hence, numerous generations occur during the year. Moreover, the biology of this pest was investigated in a relatively recent work in Shambat, Sudan, at an average mean temperature of 25 ± 0.16ºC. and 32.5% R.H. (Salih, 1991). Accordingly, the duration of the immature stages were 6.2, 15.4 and 21.5 days for the egg, nymphal and egg to adult stages, respectively. The female bug lived for an average of 12.5 ± 0.83 days and laid an average of 189 ± 22.78 eggs. However, in Thailand it was found that the average life span of adults were 73.87 days for males

92 and 53.93 days for females. The number of eggs laid averaged 142 – 67 eggs/female (Tigvattn, 1990).

2.2.4. Ecology Few research materials are available regarding ecological aspects of Urentius spp. However, colonies of U. hystricellus are generally found on the lower surface of plant leaves. In a preliminary investigations of eggplant lace bug in the Gezira, central Sudan, El Amin (1998) reported that more bugs were found on the lower surface of leaves at all levels of the plant height, but the upper leaves sustain relatively more populations compared with the lower leaves. Studies in India indicated that adults of U. hystricellus were found to hibernate in plant debris, in the period from November to March. Hence, higher activity, breeding and increasing population build-up was reported during the summer period from May to September. Nine generations were recorded during this period. However, as this study indicates, it seems that relative humidity had more influence on population of U. hystricellus than temperatures. The peak population of both nymphs and adults were recorded during August, coinciding with a peak relative humidity of 79.62 ± 9.08 per cent in the same month. Another effect is that the time taken to complete one generation was found to be longer in September onwards (21 – 35 days), when relative humidity and temperatures were declining, and shorter in July – August (16 – 19 days), when both climatic elements were high (Singh and Mann, 1986). In Thailand, Tigvattn (1990) showed that the highest infestation of eggplant by the same pest and most crop losses occurred mainly during March – June. On the other hand, in the Sudan, U. hystricellus may occur in all seasons but is most abundant late in winter season during January

93 and February. No diapausing stage of the pest was reported in this country (Pollard, 1955; Schmutterer, 1969, and Salih, 1991). One of the ecological factors that found to affect the eggplant tingid bug is the plant age. Vaeravel and Bhaskaran (1994) studied such factor in India and proved that, plant age did affect the incidence and build up of U. hystricellus on eggplant.

2.2.5. Distribution U. hystricellus is found distributed in several countries throughout the world, but mainly in south Asia (e.g. India, Thailand and Pakistan) and Africa (e.g. Rhodesia, Tanzania, Ethiopia, Kenya, Uganda, Niger, Senegal, Egypt and Sudan). In the Sudan the pest has been reported almost from the northern, central, eastern and western parts of the country (Pollard, 1955; Drake and Ruhoff, 1965; Schmutterer, 1969, and Tigvattn, 1990).

2.2.6. Host plants The main cultivated host plant of the pest is the eggplant, Solanum melongena L. Other host plants among the family Solanaceae include: Potato, Solanum tuberosum (attacked occasionally), "Gubbein", Solanum dubium Fresen. (a weed grown widely in Sudan and serves as the most important alternative wild host plant), Solanum xanthocarpum and S. indicum (reported in Thailand), garden egg, Solanum integrifolium (reported in Ghana), Datura stramonium L. and D. innoxia Mill. (reported in Sudan) (Schmutterer, 1969; Brempong - Yeboah and Okoampah, 1989; Tigvattn, 1990, and Salih, 1991). The rest of host plants belong to the family Malvaceae, and include cotton, Gossypium sp., reported in Pakistan (Rasool et al., 1986) and "Hambouk", Abutilon spp.,

94 which has been reported in Sudan (Pollard, 1955) and Pakistan (Rasool et al., 1986). However, in contrast to what has been stated above on host range, Singh and Mann (1986) in India, declared that cotton (Gossypium hirsutum and G. arboreum) and Datura stramonium L., as well as many other tested plants, are not suitable hosts for U. hystricellus, because females did not oviposit on these plants even though survived for 1 to 6 days when confined to them.

2.2.7. Damage and economic importance Eggplant may be subjected to attack by the lace bug, U. hystricellus, as early as the seedlings stage of plant growth (El Amin, 1998). According to Pollard (1959) the stylets of adults and nymphs are inserted into the leaf from either surface, and terminate intracellularly, generally within a palisade cell, sometimes in a mesophyll cell, or in rare cases in the vascular elements, from which cells the insects derived their nourishment. Such feeding activities lead to depletion of plant sap which cause pale yellow discoloured areas on the leaves. Toxicogenic studies indicated only localized toxic feeding effect of bugs on the plants. However, discoloured areas may be enlarged during heavy infestation. Finally the leaf curls downwards, shrivels, turns brown, dries up and drop to the ground. As a consequence of bugs colonizations, black excreta and cast skins of the pest may be found covering the leaves, mainly on the lower surfaces. Plant growth and fruit setting may be greatly affected. Fruits developed after infestation showed decreased levels of carbohydrates and proteins, thus, become undersized, wrinkled and very liable to attack by other pests. U. hystricellus was, therefore, considered as a major pest of

95 eggplant in the Sudan and several countries (Pollard, 1955; Schmutterer, 1969; Jamal et al., 1979; Singh and Mann, 1986, and El Amin, 1998).

2.2.8. Natural enemies No natural enemies of U. hystricellus are yet known in the Sudan, except for spiders which were recorded in small numbers associated with the pest on eggplant, in the Gezira of central Sudan (El Amin, 1998). However, parasitic insects reported elsewhere include some tachinid, scelionid and chalcid species (Mani, 1972).

2.2.9. Control Cultural methods Cultural practices which can reduce or delay infestation by these bugs may include the followings: - Removal of the previous season crop residues (Schmutterer, 1969) - Eradication of weeds such as "Gubbein", Solanum dubium Fresen., in and around fields of eggplant (Schmutterer, 1969). - Cultivation of resistant varieties. The local cultivar "Wizzo" was found to be more tolerant to the bug infestation than the other varieties grown in Sudan (Salih, 1991). Botanical insecticides Neem extracts were found very effective in controlling eggplant lace bug. Aqueous extract of neem seed kernels at 5% W./V. (50 grammes seed powder/ 1 litre water) significantly reduced infestation by the pest, hence, the quality of fruits was improved and its quantity increased significantly over the control. Such results were found to be comparable with those obtained by some conventional insecticides e.g. malathion 57% EC (Cythion), kafil 10, and omethoate (Folimat) 80% EC (Satti and Nasr, 1999, 2000).

96 Chemical control Heavy lace bug infestation on eggplant can be controlled by repeated application of insecticides. Chemicals showed significant effect in controlling this pest are, carbaryl (Sevin), malathion 57% EC, and omethoate (Folimat) 80% EC, with the latter one being the best (Salih, 1991).

2.3. "Adasi" lace bug 2.3.1. Taxonomy According to Drake and Ruhoff (1965) this pest was classified as follows: Scientific name : Urentius euonymus Distant Synonyms : Urentius abutilinus Priesner and Alfieri : Urentius maculatus Drake : Urentius hoggari Bergevin : Urentius nanus Bergroth : Prionostirina nana Schumacher Subfamily : Tinginae Laporte Family : Tingidae Laporte Order : Hemiptera

2.3.2. Distribution Drake and Ruhoff (1965) stated that the pest was recorded in Ceylon, India, Israel, Syria, Turkey, Egypt, Sudan and Algeria. The pest was also reported from Pakistan by Baloch et al. (1977, 1978), as one of the important pests of Abutilon spp.

97 2.3.3. Host plants The major host plants of U. euonymus include: Abutilon spp. (e.g. A. pannosum (Forst. f.) Schlecht. and A. figarianum Webb.); Cajanus cajan (L.) Huth. (= C. indicus K. Spreng); Helianthemum lippii; Sida cordifolia, and Sida alba L. (Drake and Ruhoff, 1965; Schmutterer, 1969, and Baloch et al., 1977, 1978).

2.4. "Sunflower" lace bug 2.4.1. Taxonomy The taxonomy of this pest was also derived from Drake and Ruhoff (1965). Scientific name : Galeatus scrophicus Saunders Synonyms : Galeatus semilucidus Jakovlev : Cadmilos retiarius Distant : Galeatus retiarius Fletcher Subfamily : Tinginae Laporte Family : Tingidae Laporte Order : Hemiptera

2.4.2. Description The morphological description of G. scrophicus was studied in Shambat, Sudan by Guddoura (1977). The head is black and convex, eyes black and prominent, rostrum black reaching coxa of middle legs. The antennae with four segments and brown to dark brown in colour; basal segment cylindrical, longer than second segment and with small hairs; second segment about half the basal, with hairs; third segment, longest, with numerous hairs like spines; fourth segment shorter than third and longer than first and second segments, swollen with hairs like spines.

98 Pronotum dark brown, covered with a net-work like structure and dark brown median carina. Forewing lacy, whitish- brown, very much wider and longer than abdomen, narrow at base and lacking spines. Hindwing whitish with brown veins. Legs reddish to brown, femora with brown small spines on lower margin, tibia segments with hairs, arolia brown and claws black. The total body length of male and female G. scrophicus is 2.90 mm and 3.12 mm, respectively. The dorsal surface of abdomen is dark brown to blackish in colour and the lower surface is dark.

2.4.3. Life history Since there were no biological studies elicited on G. scrophicus in Sudan, it is worthy to state here some notes of research findings recorded elsewhere on this aspect. According to Al Mallah (1999) the average number of eggs laid by females of G. scrophicus in Iraq averaged 143.1. The average incubation periods, nymphal stage, male and female longevity were 8.57, 22.2, 22.8 and 29.3 days, respectively. However, in detailed laboratory study in India, Verma et al. (1974) found that, the adults mated 2 – 3 hours after emergence. The eggs incubation period averaged 6.9 days. The nymphal durations lasted 2.0, 2.0, 1.7, 1.5 and 3.3 days, for the five instars, respectively. Thus, the complete nymphal stage averaged 10.1 days, and 56.8% of nymphs were survived to complete their development to adult stage. The male and female adults survived an average of 20.5 and 28.1 days, respectively.

2.4.4. Ecology In India an outbreak of G. scrophicus was reported on sunflower during May – September, 1973 (Verma et al., 1974). Moreover, in May

99 1975, a population of up to 250 – 300 nymphs + adults was counted per single leaf (Rao and Thirumalachar, 1977). However, a study in Iraq showed that the pest occurred on sunflower from April to November during 1996 and 1997. Apositive and significant correlation was depicted between the number of insects and temperature, and significant negative correlation with humidity. It was found that the insects preferred the lower part of the plant and the lower surface of the leaf (Al Mallah, 1999).

2.4.5. Distribution G. scrophicus is a pest that was detected earlier in Sudan, since it has been collected and found preserved in the Insects Collection of the Agricultural Research Corporation as early as 1926. It is reported as a pest of sunflower crop in the Blue Nile and Khartoum Provinces. Later on, Guddoura (1977) confirms the presence of this pest and its damage to the same crop in the Sudan. In a world wide scale G. scrophicus was found exerting variable incidence of damage to the crop, in several countries like Iraq (Al Mallah, 1999), Turkey (Onder and Lodos, 1983) and India (Verma et al., 1974; Rao and Thirumalachar, 1977, and Rohilla et al., 1980). It is also found in almost all Mediterranean countries (both in Africa and Europe), U.S.S.R., Senegal, South Africa and Canary Islands (Drake and Ruhoff, 1965).

2.4.6. Host plants These include mainly sunflower, Helianthus annus (Drake and Ruhoff, 1965; Guddoura, 1977; Rao and Thirumalachar, 1977; Onder and Lodos, 1983, and Al Mallah, 1999) and the niger plant, Guizotia abyssinica (Rao and Thirumalachar, 1977). Onder and Lodos (1983) also referred to the family Compositae in general, as host plants.

100 2.4.7. Damage Nymphs and adults of G. scrophicus generally feed by sucking the sap from different parts of sunflower plant, such as leaves, stems and flower bracts, which gradually turned yellowish in colour (Verma et al., 1974). In other way, the symptoms of damage were described by Rao and Thirumalachar (1977) as white patches on the leaves where in the later stages, dark brown patches and crinkling occurred.

2.4.8. Control No control measures were recommended for this pest in the Sudan.

101

3. MATERIALS AND METHODS

3.1. Field experiments A number of field experiments were executed at Shambat, Experimental Farm of the Faculty of Agricultural Studies – Sudan University of Science and Technology. The purposes were to study the population abundance of Urentius hystricellus Richter, Urentius euonymus Distant and Galeatus scrophicus Saund., and their natural enemies (predators), on eggplant (Solanum melongena L.), pigeon pea (Cajanus cajan (L.) Huth.) and sunflower (Helianthus annus L.), respectively. Most of these experiments covered the different seasons (summer, autumn and winter) for three consecutive years (2000 – 2002), as explained below:

3.1.1. Eggplant The first experiment of eggplant was conducted in winter season of the year 1999/2000, followed by six experiments covering different seasons in the period 2000 – 2002, therefore, a total of seven planting seasons were performed. Each experiment simply consisted of a plot (5.0 x 6.0m) with five ridges, replicated three times and planted to eggplant seedlings (cv. Black Beauty) as recommended by the Agricultural Research Corporation (Burgstaller et al., 1984). After crop establishment, about 21 days of sowing (transplanting), weekly counts of U. hystricellus and its predators, were carried out. During the count, ten plants were selected randomly in a cross-diagonal lines of each plot, then five leaves were chosen randomly from the different plant heights (two upper, one middle and two lower), and examined. Therefore, the number of insect pests and predators were

102 recorded per 50 leaves per each plot. Such method of sampling which seems to be simple and easy, was adopted by several authors working on vegetable pests in Sudan (Satti et al., 1998; Satti and Nasr, 1999, 2000). However, for understanding the distribution of lace bugs between the upper and lower surfaces of plant leaves, as well as the relative abundance of adults and their immature stages, hence, the numbers of adults and nymphs found on either sides of the leaves were recorded separately during different seasons. Statistical analysis of such data were performed using T-test.

3.1.2. Pigeon pea Since pigeon pea is a perrenial crop only three experiments were found enough to cover the three years of the field study, where each experiment was renewed after one year from planting. Plot size was 5.0 x 6.0 m, and seeds were sown 60 cm apart in ridges running in a north / south direction. Three replications were used each time. Counts of adults and nymphs of U. euonymus and its predators and the analysis of data were done in the same way as mentioned for U. hystricellus, with the only difference here is that the unit of sampling was a compound leaf. Hence, the number of insects were recorded per 50 compound leaves per plot.

3.1.3. Sunflower Two experiments on sunflower were conducted during the winter (October/2001 – January/2002) and autumn (August – October/2003) seasons. The susceptibility of two varieties, HYSUN 33 (the most important one grown commercially in Sudan) and HSHA 9, was tested against the lace bug (G. scrophicus) infestation in these experiments. Each variety was grown in a plot (5.0 x 6.0m) of five ridges (north / south) with three replications. Seeds were sown 20 cm apart, thinned to

103 one plant per hole after germination. Method of sampling, collection and analysis of data were done in a similar way as described for the eggplant. T-test was also used to compare the level of infestation between the two varieties.

3.2. Field surveys Different hosts plants of the lace bugs and /or their predators, were investigated throughout the year in Khartoum State, concentrating at Shambat area, as explained below: 3.2.1. Lace bugs and their hosts plants Extensive seasonal surveys were carried out, where several species of plants among weeds, ornamentals, shrubs and trees were investigated, so as to confirm the already reported hosts, find new hosts and to recognize new species of lace bugs whenever possible. Plants showed the highest infestation were subjected to weekly counts of insects. The number of adults and nymphs were counted on upper and lower surfaces of five leaves (two upper, one middle and two lower) per plant, in ten randomly selected plants in a field. Therefore, the number of insects per 50 leaves were recorded from one place and repeated in other two locations (as replicates) chosen randomly in Shambat area.

3.2.2. Predators and their hosts plants The predators associated with the lace bugs were counted simultaneously on the same hosts plants harbouring the lace bugs, in a similar way as their preys. Because of their general feeding habits, such predators were also found associated with other pests (e.g. aphids), on crops not serving as hosts for the lace bugs. From these crops, three forage plants which are grown widely in the area, were surveyed where the population abundance of predators were evaluated. These crops included "Berseem", Medicago sativa L., forage sorghum, Sorghum bicolor (L.), Moench and maize, Zea mays L. For the first crop the

104 number of predators were counted per one square metre per plot, whereas for the latter two crops, twenty five randomly selected plants per plot were investigated. Three replications were done for each sampling, which continued in a weekly intervals for three consecutive years (2000 – 2002).

3.3. Laboratory work 3.3.1. Monitoring of lace bug parasites Host plant leaves infested with immature stages of the lace bugs, U. hystricellus and U. euonymus, in the field were taken once per season (summer and winter) from eggplant and pigeon pea, placed in petri-dishes provided with moist filter paper and kept in the laboratory. Such samples were observed daily under the binocular microscope in search of parasites for each pest species.

3.3.2. Morphological presentation of important lace bug species Since new lace bug species were recorded for the first time in this study, illustrations of adult, last nymphal instar and some morphological parts (e.g. antennae and wings) of these pests, through slides preparations, were found to be necessary. This included identified, as well as unidentified species. Moreover, it was particularly aimed to distinguish between the two Urentius spp. on their different alternative host plants, as there seems to be some confusion between them. Adult and last nymphal stage of each species were collected from their hosts in the field during April 2003, and the whole insects and certain morphological parts were mounted on slides. The forewings were detached with the help of a needle and forceps, placed onto the slides, on which Euopral mountant was added and covered with cover slips. The treatments applied to other specimens in slides preparations, were found to be unnecessary, as these wings are lacy and transparent.

105 However, the procedures of slide preparation adopted by several scientists (Pruthi, 1925, and Scuder, 1959) were used as basic references in preparing the different specimens (other than the wings). Accordingly, the insects were placed for two hours in watch glasses containing a cold solution of 10% caustic potash (KOH). The specimens were then washed through a series of ethanolic concentrations of 30%, 50%, 70% and 90% (5 minutes in each). Complete body samples of adults (male or female) and nymphs were put separately on normal glass slides, where as cavity slides were used for thicker specimens (adults of certain species). A new technique applied here is that the removal of abdominal part was found useful in appearing the details of wing venation and the network of the posterior extension of the pronotum more clearly under the microscope. Sometimes parts of the body were detached and mounted alone whenever needed. Drops of Euopral were added on the slides, on which cover slips were placed carefully, so as not to alter the right position being adopted for the specimens and not to trap air-bubbles. The slides were left for many days to dry under laboratory conditions. Morphological drawings were made possible with the help of a Drawing Tube mounted on an illuminated microscope. A finely scaled ruler was used for morphometric studies. Unidentified new lace bugs were named to their major host plants in the text. An attempt was made to identify some species to generic level depending on some literature. However, samples of such new insects were preserved in glass vials containing 70% alcohol, with 5% glycerine, to be send abroad for final determination of species.

3.3.3 Durations of the pre-adult stages of important lace bug species on some of their major host plants Pre-oviposition period, egg-incubation time and duration of the different nymphal stages of certain species of the lace bugs were studied

106 in the laboratory, during autumn (August – November) and winter (January – February) seasons of 2001/2002. The lace bug species and their respective host plants used for rearing are listed in the following table. Insect species Host plants Urentius hystricellus Solanum melongena (Eggpant) Solanum dubium (Gubbein)

Urentius euonymus Cajanus cajan (Pigeon pea) Abutilon sp. (Hambouk)

Galeatus scrophicus Helianthus annus (Sunflower) Lactuca taraxifolia (Moleita)

All the above host plants were sown in small plastic pots and, when they reached three-leaves stage, were used for studying the pre- oviposition and incubation periods. The last nymphal stage of each lace bug concerned in this study were collected in petri-dishes from their host plants in the field. Soon after adults emerged, three sexed pairs of each species were released on their respective host plant seedling of the plastic pots mentioned above. Such seedlings were enclosed with a big-size lamp glass, covered on its top vent with muslin cloth tied with a rubber band (Pl. 1). Three replications of cages were made for each lace bug species. These insects were transferred daily to new pots (up to seven days), with each one being labeled and dated. Starting five days from removal of ovipositing insects from the first cages, seedlings were subjected to daily inspection for eggs hatchability under the binocular microscope. The number of days from adults emergence up to the day of the first oviposition on seedlings was indicated as a pre-oviposition period, while the days from insects removal to egg hatching represent incubation period.

107

Plate 1. A sample of cages used for rearing and studying pre- oviposition and eggs-incubation periods of different lace bug species

108 A number of newly hatched nymphs (15 – 20 insects) from each lace bug species were placed individually in petri-dishes lined with moist filter paper and a fresh plant leaf (renewed daily) for feeding. These dishes were kept in the laboratory and, inspected twice a day (morning and evening), during which moulted insects were recorded. The data and observations reported were analysed for each season, where the average durations of the various pre-adult stages were computed for each pest species.

109 4. RESULTS

4.1. Encountered lace bugs and their host plants The results of the continuous inspection on various weeds, crops and other natural vegetations surveyed during the current study have revealed various species of lace bugs and their host plants in such limited area (Khartoum State) of the country. A total of nine lace bug species and nineteen host plants were reported. However, from these figures, three pest species and six hosts were already known, while six pests and thirteen hosts were new records. Since new lace bugs were not yet identified, each species was named to its major host plant in the text of this thesis. Hence, the encountered lace bug species and their host plants were listed in Table (1). Almost, all the imaginal and nymphal (5th instar) stages and some morphological parts (e.g. wings, antennae and parameres of the male sex) of the nine detected lace bug species were illustrated with drawings in Figures 1 – 22. Such drawings help in the recognition of each species, especially of those possessing a range of host plants like Urentius spp. and Galeatus scrophicus. Moreover, rearing of some lace bugs taken from certain host plants (e.g. Cajanus cajan and Abutilon sp.) on caged eggplant seedlings (Pl. 1), confirmed the differentiation made between the two Urentius spp. on their respective host plants (Table 1), based on morphological differences. As with regard to these two criteria , all insects collected from non Solanaceous host plants were died within three to five days when confined to eggplant seedlings. On the other hand, clear morphological differences were detected between U. hystricellus and U. euonymus. The adult and last instar nymph were larger in size in the former species (Figs. 1 and 3) compared with the latter one (Fig.6).The

110

111

112

113

114

115 Fig. 3. Urentius hystricellus collected from Solanum dubium; a) Adult. b) Last instar nymph.

116

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118

119

Fig. 8. Urentius euonymus collected from Abutilon sp.; a)Antennae b) Parameres c) Last instar nymph d) L. wing

120

Fig. 9. Urentius euonymus collected from Sida alba; a) Antennae b) Parameres c) R. wing

121

Fig. 10. Urentius euonymus collected from Chrozophora plicata; a) Male wing b) Female wing c) Last instar nymph d) Parameres

122

Fig. 11. Urentius euonymus collected from Rhynchosia memnonia; a) Antennae ♂ b) Last instar nymph c) R. wing ♂

123

Fig. 12. Galeatus scrophicus collected from Helianthus annus; a) Last instar nymph b) Adult

124

Fig. 13. Galeatus scrophicus collected from Helianthus annus; a) L. wing b) Antennae ♀ c) Parameres

125

Fig. 14. “Rehan” lace bug collected from Ocimum basilicum; a) Adult ♂ b) Last instar nymph

126

Fig. 15. "Adana" lace bug collected from Rhynchosia memnonia; a) Antennae ♂ b) Adult c) Male wing d) Female wing e) Parameres

127

128

Fig. 17. "Sidir" lace bug collected from Ziziphus spina-christi; a) Adult ♂ b) Last instar nymph

129

Fig. 18. "Sidir" lace bug collected from Ziziphus spina-christi; a) Antennae ♀ b) L. wing ♂ c) Parameres

130

Fig. 19. "Guddeim" lace bug collected from Grewia tenax; a) Adult ♀ b) and c) Last instar nymph

131

Fig. 20. "Guddeim" lace bug collected from Grewia tenax; a) Antennae ♀ b) Parameres c) L. wing

132

Fig. 21. "Andrab" lace bug collected from Cordia sinensis; a) Adult ♀ b) Last instar nymph.

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Fig. 22. "Andrab" lace bug collected from Cordia sinensis; a) Antennae ♂ b) Parameres c) L. wing ♂

134 average sizes of the females (length x width) were 3.11 ± 0.02 x 1.60 ± 0.11 mm, and 2.38 ± 0.33 x 1.13 ± 0.50 mm in the two species, respectively. The last nymphal stage measured 2.38 ± 0.15 x 1.29 ± 0.02 mm in U. hystricellus and 1.88 ± 0.03 x 1.03 ± 0.01 mm in U. euonymus. Such differences in sizes were, therefore, appeared in wings, antennae and parameres (Figs. 2 and 4 vs. 7 and 8). However, considering the lacy patterns of the wings, a double rows of cells shown in the hemelyteron costal area of U. hystricellus (Figs. 2, 4 and 5) was one of the prominent distinguishing features, when compared with a single row in U. euonymus (Figs. 7 – 11). The marginal spines of nymphs were also longer in size showing clear apical branching in U. hystricellus (Figs. 1 and 3), compared with those of the other species (Figs. 6, 8, 10 and 11). An additional character to be added here is the difference in colour observed on terminal parts of legs (Tibiae and tarsae) and antennae of the two species. The colour being light brown in U. euonymus and dark brown (same colour of body) in U. hystricellus. Most of the encountered lace bug species were found highly specialized in their host range, feeding mainly on one host or on some few closely related plants. Although, U. euonymus was found on hosts representing three families (i.e. Fabaceae, Malvaceae and Euphorbiaceae), hosts of U. hystricellus were yet restricted entirely among Solanaceae. Similarly, seven host plant species, all of the family Compositae, were reported for Galeatus scrophicus. All the host plants of the different lace bug species reported in this study, except Solanum incanum, were found abundant in different parts of the State (Khartoum, Khartoum North and Omdurman). It is also worthy to state that, the author had chances during the research period to visit some other regions in the country, where some notes were reported. Accordingly, Galeatus scrophicus was observed infesting "Rantouk" (Xanthium brasilicum) in

135 Gezira (Wad Medani area), Blue Nile (Damazine area) and White Nile (Kosti area) States (December, 2002). In the Northern State (El Ghaba area) a high population of Urentius hystricellus was observed infesting Solanum incanum, while those of U. euonymus were colonizing Cajanus cajan, Abutilon sp., Chrozophora plicata and Rhynchosia memnonia (September, 2003). The latter species was also detected on Abutilon sp. in Gezira and White Nile States. Moreover, "Guddeim" lace bug was also collected from Grewia tenax in Southern Darfur (Kutum area) during November of 2002. 4.2. General morphological and behavioural observations The overall forms, colours and sizes of the detected species were varied among different genera of the lace bugs. In all species males were smaller than the females. These insects seem to camouflage themselves according to the ecological situations where they live. When forms are regarded, for instance the adult of Thaumamannia sp. is nearly hemispherical in shape (Fig. 16), and “Adana” lace bug is long and slender (Fig. 15), while the other seven species are more or less oval in shapes. It was observed that the last instar nymphs in all species were found characterized by having wings covering almost half of their body length. This character is known in locusts and other hemimetabolous insects. Adults of Urentius spp., “Sidir’ lace bug, and “Andrab” lace bug are some what yellowish brown in colour, resembling to some extent the colour of hairs and/or young branches of their respective host plants. Urentius euonymus adults are more lighter in colour compared with U. hystricellus. On the contrary, nymphs of the former species are brownish with mosaic appearance, as some dark brown to blackish spots are found on certain points of their dorsal body surface (prominent on pronotum, lateral body sides and terminals of wing rudiments), while nymphs of the

136 latter species are yellowish brown. However, nymphs of “Sidir” lace bug and “Andrab” lace bug were blackish brown and brown, respectively. The purplish brown colour shown by “Rehan” lace bug seems to simulate those purplish blotches seen on “Rehan” plant. Adults of Thaumamannia sp. are blackish in colour all round, while their nymphs are yellowish brown. However, such nymphs represent a typical camouflaging insect, as the extensive hairs they bear (Fig. 16), were found exactly mimicing those hairs beared by their host plant, Rhynchosia memnonia, both in shape and colour, as seen under the microscope. Similarly, adults of “Guddeim” lace bug are blackish in colour all round, but their forewings, are exceptionally white. Each wing was characterized by a central subcostal circular blackish spot. It is wonderful to say that the orange colour of the newly moulted nymphs and the pinkish colour they acquired later, during successive metamorphosis, was extracted from the glowing fruit berries of Grewia tenax. Adults of Galeatus scrophicus are dark brown to reddish brown in colour, with their nymphs being blackish brown or sometimes brown. Different behavioural habits were shown by the various species of lace bugs reported during this study. The two Urentius spp., G. scrophicus and “Rehan” lace bugs were more sluggish pests, both in the imaginal and nymphal stages, feeding in groups and tend to disperse only when disturbed. This gregarious habit is mainly a characteristic of nymphs, and the scattered insects after disturbance were soon reassembled again in the same place or in other locations making new colonies. Adults of the former and latter species rarely take wings, but adults of G. scrophicus either quickly drop of their host plant down wards or take off wings, when somebody approaching. On the other hand, Thaumamannia spp., “Sidir”, “Guddeim”, and “Andrab” lace bugs, especially adults, were generally found creeping swifty in different

137 directions on the leaves and branches (mainly on terminal parts) of their host plants. This character was mostly obvious in “Guddeim” lace bug and to some extent in Thaumamannia sp., in relative to the others, which make it difficult to count such running insects during periodical samplings. In addition, some adults especially those of “Guddeim”, “Andrab” and “Sidir” lace bugs could also take wings before the performance of count, if more disturbances to the leaves and branches occurred during investigations. Moreover, “Adana” lace bugs stand with their long legs on the leaves and having wings broadened posteriorly, they used to raise and lower their posterior body part in a dramatic way, look as if they were sailing boats in a wavy sea.

4.3. Seasonality of lace bugs and their distribution within host plants. Regular weekly counts during different seasonal experiments were done only for three lace bug species (viz., Urentius hystricellus, U. euonymus and Galeatus scrophicus). Sporadic counts and observations on population abundance were reported for the rest of recorded species. Since the population build up of insects are mainly affected by climatic conditions, it was found necessary to present here a data of three years (2000-2002) concerning the monthly, mean maximum and minimum temperatures and the total rainfall, as recorded by Shambat Meteorological Station (Fig.23). The weekly population means of U. hystricellus on eggplant for each growing season are presented in Table (2), and summarized as monthly mean counts in Table (3). It is clear from these figures, that there were two periods during the year where the population of eggplant lace bug showed the highest level. These periods represent the end of the winter season (February-April) (a peak of 424.67 insects in February, 2000, 262.87 in March, 2001 and 328.59 in March, 2002) (Table 3), and

138

50

40

30 Max Min 20 Temp Rainfall 10

0 Jan. Mar. May July Sep. Nov. -2000

50

40

30 Max Min 20 Temp Rainfall 10

0 Jan. Mar. May July Sep. Nov. -2001

50

40

30 Max Min 20 Temp Rainfall 10

0 Jan. Mar. May July Sep. Nov. -2002

Fig. 23. The monthly, mean maximum and minimum temperatures and total rainfall, during three consecutive years (2000 – 2002) at Shambat area.

139

Table 2. The weekly population means (per 50 leaves) of Urentius hystricellus on eggplant, during different growing seasons (1999 – 2002), at Shambat. Growing seasons 1999 / 2000 2000 2000 / 2001 2001 2001 / 2002 Date Mean Date Mean Date Mean Date Mean Date Mean 15.12.9 25.67 27.4.0 2.00 16.12. 16.67 6.7.0 14.67 17.12. 25.00 9 12.33 0 40.33 00 9.00 1 182.3 01 11.00 22.12 56.00 4.5 56.00 23.12 20.33 13.7 3 24.12 17.67 29.12 23.67 11.5 23.33 30.12 20.67 20.7 627.0 31.12 5.67 5.1.00 30.33 18.5 24.00 6.1.01 14.33 27.7 0 7.1.02 19.33 12.1 200.33 25.5 55.00 13.1 40.00 3.8 420.3 14.1 23.67 19.1 254.00 1.6 17.67 20.1 39.00 10.8 3 21.1 33.67 26.1 288.67 8.6 31.67 27.1 36.00 17.8 336.3 28.1 114.33 2.2 503.33 15.6 68.00 3.2 31.67 24.8 3 4.2 80.67 9.2 429.67 22.6 170.33 10.2 15.67 31.8 351.0 11.2 183.67 16.2 477.00 29.6 6.67 17.2 51.00 7.9 0 18.2 211.00 23.2 396.33 6.7 7.00 24.2 109.00 14.9 372.3 25.2 338.67 2.3 318.67 13.7 4.67 3.3 295.67 21.9 3 4.3 326.00 9.3 211.67 20.7 4.33 10.3 355.67 28.9 319.0 11.3 377.67 16.3 112.00 27.7 8.00 17.3 289.33 28.9* 0 18.3 272.00 23.3 112.00 3.8 24.3 264.67 5.10 288.0 25.3 200.67 30.3 131.67 31.3 227.00 7.10* 0 1.4 210.33 6.4 167.00 7.4 340.00 * 351.3 8.4 129.00 13.4 14.4 267.67 12.10 3 15.4 21.4 166.00 19.10 396.3 28.4 89.67 26.10 3 5.5 49.00 2.11 411.3 12.5 85.33 9.11 3 19.5 16.11 395.3 23.11 3 662.0 0 408.6 7 190.0 0 333.3 3 111.0 0 17.00

140 19.00 6.00 5.67 3.33

* and **: Single count on seedlings checked by Urentius feeding, in two experiments conducted during autumn, in late August and early September, respectively.

141

Table 3. The monthly mean counts (per 50 leaves) of Urentius hystricellus on eggplant, during different growing seasons (1999 – 2002), at Shambat. Growing seasons 1999 / 2000 2000 2000 / 2001 2001 2001 / 2002

Mont Mea Month Mean Mont Mean Mont Mean Month Mean h n h h

Dec. 31.33 May, 35.92 Dec. 15.33 July 311.0 Dec. 01 17.89 99 00 00 01 8

Jan. 127.0 68.53 28.50 Jan. 02 20.59 00 8 June Jan. Aug. 333.3 01 3 5.67 33.59 Feb. 147.42 Feb. 424.6 July, Sept. 7 00 Feb. 388.5 262.8 8 Mar. 328.59 Mar. 7 Oct. 230.1 Mar. 3 217.5 April, 180.00 April 250.1 Nov. 0 02 April 7 01 149.3 4 8.50 May 74.67 01

142 the period following the rainy season (September-October) (a peak of 388.58 insects in September, 2001; Table 3). Both adults and nymphal stages were recorded in almost all counts throughout the year, which may suggest that activity and breeding of U. hystricellus could occur all the year round without any resting stage in this country. Although, rainfall appear to have a negative effect in suppressing the lace bugs mechanically, but high rainfall was found to be followed by tremendous population build up of U. hystricellus in the field. Therefore, the two experiments conducted during August and September of 2001 (a year witnessed the highest rainfall during the study period; Fig. 23), were completely checked while in the seedlings stages (Pl. 2 a) due to the high infestation inflicted by the eggplant lace bug (a mean of 662.00 and 190.00 insects in single count for the two experiments, respectively; Table 2). It is worthy to state that such checked seedlings mentioned above was aggravated by an outbreak of the blister beetle (Epicauta aethiops (Latr.) ( Pl. 2 d) which was observed annually in a period extending from August to October. They were controlled manually every day, otherwise no body could managed to grow eggplant during this period. Blister beetles were also observed in the area feeding, besides eggplant, on “Berseem” (Medicago sativa) and “Gubbein” (Solanum dubium), where the latter host seems to be the most preferred one among the others. The population means of U. hystricellus on “Gubbein” {Table 4} appears to follow the same trend shown on eggplant (Table 2 ). Two peaks were recorded during March-April and then October month. Again, the population of insects in September-October of the year 2001 (highest rainfall) was surpassing those of the preceding and following years (Fig. 24)

143

Plate 2. Severity of damage induced by Urentius spp. and a blister beetle on different hosts; a) Ruined eggplant seedling by Urentius hystricellus b) Complete damage of Solanum dubium by U. hystricellus

144 c) Complete damage of Abutilon sp. by Urentius euonymus d) Eggplant leaves completely chewed by Epicauta aethiops

145

Table 4. The weekly population means (per 50 leaves) of Urentius hystricellus on "Gubbein" (Solanum dubium), during three consecutive years (2000 – 2002) of surveys in Shambat area.

Year 2000 2001 2002 Year 2000 2001 2002 Mean Mean Mean Mean Mean Mean Date Date 2/Jan. 290.00 227.33 73.00 3.7 1.00 16.00 11.00 9.1 300.00 275.67 81.00 10.7 0.00 11.33 32.00 16.1 202.00 90.00 11.00 17.7 1.00 33.00 14.00 23.1 130.00 9.00 92.00 24.7 9.00 60.00 12.00 30.1 16.25 81.00 39.67 31.7 13.00 44.00 25.67 6.2 57.50 13.00 88.00 7.8 18.00 25.00 5.00 13.2 3.00 1.00 117.00 14.8 32.00 21.00 9.00 20.2 1.33 9.00 159.33 21.8 16.00 50.00 21.00 27.2 4.00 22.00 210.00 28.8 83.00 101.00 30.00 6.3 19.00 12.00 290.00 4.9 38.00 120.00 64.00 13.3 77.00 19.67 488.00 11.9 76.00 179.00 116.33 20.3 55.00 7.33 98.00 18.9 100.33 154.33 154.67 27.3 76.67 14.33 200.00 25.9 180.00 278.00 178.33 3.4 80.00 11.00 25.67 2.10 170.00 360.00 200.00 10.4 190.00 4.67 120.00 9.10 280.00 400.00 118.00 17.4 257.00 8.00 71.00 16.10 200.00 390.00 210.00 24.4 130.00 17.67 25.33 23.10 240.00 200.00 205.00 1.5 91.00 13.00 88.00 30.10 200.00 180.00 188.33 8.5 65.00 0.00 24.67 6.11 134.00 34.33 15.67 15.5 39.33 0.00 88.00 13.11 234.67 99.00 110.00 22.5 50.00 3.00 42.00 20.11 352.00 10.00 122.33 29.5 60.00 45.00 30.00 27.11 103.67 20.00 100.00 5.6 43.00 31.00 21.33 4.12 378.67 4.00 98.00 12.6 29.00 2.00 32.67 11.12 302.67 9.00 86.00 19.6 59.00 7.00 15.67 18.12 269.00 70.00 18.00 26.6 20.00 10.00 10.33 25.12 254.00 60.00 30.67

146

147 Comparisons of the distribution of different stages of U. hystricellus between the two surfaces of plant leaves, on eggplant and “Gubbein” host plants during different seasons, are presented in Tables (5) and (6), respectively. The pest in its all stages were mainly confined to the lower leaf surfaces of the two host plants in all seasons, with the population means difference being significant in most cases. An exception was that the mean counts of adult stage on eggplant were found to be higher on upper surfaces of the top leaves, but no significant differences were detected during various seasons (Table 5). In case of Urentius euonymus on pigeon pea (Cajanus cajan) and “Hambouk” (Abutilon spp.) (Tables 7 and 8), two population peaks were also found (Figs. 25 and 26). The first period of population build up was extending over along time from February to July (end of winter and whole summer seasons), where variable monthly trends were shown in different years. The other period of population increase was in September-October (Figs. 25 and 26). The two hosts were more or less showing similar trends, but generally the population counts of insects were much lower on the pigeon pea than on the wild host, “Hambouk” (Figs. 25 and 26). Similar to what has been mentioned for U. hystricellus, counts of U. euonymus during the second period of population increase (September-October), were relatively higher in the year 2001 (following a season of high rainfall), than in the years 2000 and 2002. Adults and nymphs of U. euonymus were recorded all the year round on “Hambouk”, a case which was not settled for the pigcon pea, since the latter crop was found free of lace bugs (especially nymphs) in some counts during the different experiments (Table 7). However, the occurrence and breeding of this pest on various host plants among different families (Fabaceae, Malvaceae and Euphorbiaceae) were proved through the surveys and

148 Table 5. Comparisons of the mean counts of different stages (a, b and c) of Urentius hystricellus, between upper and lower surfaces of eggplant leaves, during the different seasons (2001 - 2002), at Shambat.

(a): Adults / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 12.46 ± 5.67 ns 62.06 ± 8.97 ns 11.72 ± 0.36 ns

Lower 6.71 ± 3.84 25.09 ± 7.25 9.61 ± 2.25

(b): Nymphs / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 6.21 ± 2.48 49.82 ± 11.54 81.81 ± 4.57

Lower 136.71 ± 27.35 * 170.06 ± 21.06** 117.22 ± 8.93 *

(c): Adults + Nymphs / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 18.67 ± 7.38 111.88 ± 15.00 93.53 ± 4.60

Lower 143.42 ± 31.06 * 195.16 ± 28.17 * 126.83 ± 9.20 *

** = Highly significant difference ( P ≥ 0.01) * = Significant difference ( P ≥ 0.05) ns = Non significant difference.

149 Table 6. Comparisons of the mean counts of different stages (a, b and c) of Urentius hystricellus, between upper and lower surfaces of "Gubbein" (Solanum dubium) leaves, during the different seasons (2001 - 2002), at Shambat area.

(a): Adults / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 2.12 ± 0.40 5.21 ± 0.59 2.62 ± 0.62

Lower 8.73 ± 1.58 ns 21.77 ± 4.55* 20.80 ± 0.66**

(b): Nymphs / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 1.27 ± 0.90 1.18 ± 0.64 3.22 ± 0.89

Lower 48.03 ± 14.80 ns 68.36 ± 5.89** 152.05 ± 1.36**

(c): Adults + nymphs / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 3.40 ± 1.27 6.39 ± 0.79 5.85 ± 1.28

Lower 56.76 ± 16.38 ns 90.13 ± 7.06** 172.85 ± 1.76**

** = Highly significant difference ( P ≥ 0.01) * = Significant difference ( P ≥ 0.05) ns = Non significant difference.

150

Table 7. The weekly population means (per 50 leaves) of Urentius euonymus on pigeon pea, during different seasons (2000 – 2002), at Shambat.

Year 2000 2001 2002 Year 2000 2001 2002 Mean Mean Mean Mean Mean Mean Date Date 1.Jan. 0.67 4.33 0.00 16.7 4.33 1.67 56.67 8.1 0.00 2.00 0.67 23.7 0.33 5.67 23.00 15.1 2.33 0.00 0.33 30.7 0.00 10.33 43.67 22.1 2.00 0.00 4.67 6.8 0.33 5.67 0.00 29.1 7.67 3.33 0.33 13.8 7.67 4.33 1.33 5.2 14.33 0.00 2.67 20.8 4.33 0.67 0.00 12.2 22.33 0.00 0.33 27.8 4.67 1.33 0.00 19.2 14.67 5.67 0.00 3.9 3.67 38.33 1.33 26.2 2.33 7.67 8.67 10.9 5.00 41.67 10.00 5.3 3.67 0.00 6.00 17.9 6.67 30.67 7.67 12.3 10.33 0.00 0.00 24.9 13.67 42.00 71.67 19.3 7.33 4.00 0.00 1.10 11.00 9.00 23.67 26.3 3.33 17.67 3.67 8.10 2.67 29.67 0.00 2.4 29.67 14.00 0.67 15.10 1.00 16.67 4.33 9.4 4.33 7.67 0.00 22.10 9.67 25.00 2.33 16.4 38.33 0.00 27.00 29.10 3.33 22.33 6.67 23.4 50.33 9.67 0.00 5.11 0.67 20.00 4.00 30.4 113.33 21.67 0.33 12.11 0.00 15.67 0.00 7.5 120.67 41.67 0.00 19.11 0.00 19.33 8.33 14.5 59.33 19.33 6.33 26.11 0.00 14.00 21.33 21.5 70.67 20.33 0.00 3.12 61.00 4.33 10.67 28.5 53.33 33.67 0.00 10.12 104.00 3.67 24.67 4.6 18.33 11.00 263.33 17.12 49.00 0.67 16.33 11.6 40.33 17.67 40.00 24.12 30.00 7.33 6.67 18.6 33.67 17.00 113.67 31.12 38.00 5.00 3.67 25.6 13.67 10.33 50.67 7.1.2003 - - 40.33 2.7 18.67 3.33 164.00 14.1 - - 41.00 9.7 0.33 0.00 156.33 21.1 - - 52.33 28.1 - - 48.67 (-) = no count was made

151

Table 8. The weekly population means (per 50 leaves) of Urentius euonymus on "Hambouk" (Abutilon spp.), during three consecutive years (2000 – 2002), of surveys in Shambat area Year 2000 2001 2002 Year 2000 2001 2002 Mean Mean Mean Mean Mean Mean Date Date 2.Jan 83.00 114.67 69.67 24.7 25.67 120.00 137.67 9.1 110.00 88.67 70.00 31.7 33.00 160.00 66.33 16.1 90.00 50.00 111.00 7.8 41.00 90.00 50.00 23.1 39.00 1.33 25.00 14.8 29.00 110.00 60.00 30.1 9.67 10.00 60.33 21.8 50.00 195.33 39.33 6.2 54.00 20.00 290.33 28.8 15.00 220.00 75.00 13.2 14.00 29.67 524.00 4.9 91.00 560.67 77.00 20.2 140.00 1.33 438.67 11.9 160.00 424.67 70.33 27.2 180.00 20.00 350.00 18.9 319.00 359.33 233.33 6.3 77.00 58.67 362.33 25.9 312.00 248.67 223.33 13.3 98.00 70.00 209.00 2.10 360.00 1036.00 356.00 20.3 112.00 42.67 308.67 9.10 309.00 810.00 709.00 27.3 149.33 756.67 320.00 16.10 190.00 392.00 360.00 3.4 160.00 770.00 196.33 23.10 211.00 450.00 323.67 10.4 205.00 725.67 270.00 30.10 200.00 300.00 255.00 17.4 139.33 750.00 269.00 6.11 125.67 396.67 170.00 24.4 210.00 384.67 248.33 13.11 93.67 280.00 180.00 1.5 200.00 881.67 296.33 20.11 42.00 230.00 277.67 8.5 230.00 780.00 333.00 27.11 61.67 20.00 200.00 15.5 189.33 490.00 323.33 4.12 30.67 224.00 170.00 22.5 190.00 510.00 453.00 11.12 31.33 119.67 150.67 29.5 200.00 350.00 350.00 18.12 180.67 114.67 87.00 5.6 65.00 200.00 83.67 25.12 146.33 247.67 66.67 12.6 180.00 124.00 239.67 19.6 108.67 150.00 151.33 26.6 60.00 118.33 155.67 3.7 15.00 81.33 160.00 10.7 90.00 22.67 148.33 17.7 34.00 50.00 331.33

152 153 154 regular counts that were made on the previous two hosts (pigeon pea and “Hambouk”), supported by some counts on Sida sp., Chrozophora plicata and Rhynchosia memnonia during variable times of the study period (Table 9). The distribution of adults and nymphs of U. euonymus on the leaves were somehow different on the two studied hosts. During summer time the population of adults were higher on the upper surfaces of the two hosts, while in autumn and winter seasons contrastible results were recorded (Tables 10 and 11). As for the nymphs, pigeon pea showed higher population of insects on the lower leaf surfaces during all seasons, but on “Hambouk” this condition is true only during autumn (summer and winter showed higher population of nymphs on the upper surfaces) (Tables 10 and 11). The overall numbers of adults and nymphs also showed contrasting results during the different seasons on the two hosts. No significant differences were detected among all the previous data. The population abundance of Galeatus scrophicus was studied in two experiments during winter (2001/2002) and autumn (2003) seasons. Table (12) shows the weekly counts of adults and nymphs of the pest on two varieties of sunflower (HYSUN 33 and HSHA 9), during the two seasons. The population of insects increased gradually showing a peak at the end of each season. In winter a peak of 86.33 and 91.00 insects/50 leaves were recorded in January, on HYSUN33 and HSHA 9 varieties, respectively. However, the infestation incidence was very low in the autumn (the total seasonal counts were 10.67 and 95.34 insects on the two varieties) compared with the winter season (a total of 266.67 and 370.00 insects).

155

Table 9. The monthly mean counts of Urentius euonymus on three weeds-"Um Shidaida" (Sida alba), "Taroob" (Chrozophora plicata) and "Adana" (Rhynchosia memnonia) – surveyed during different months (2000 – 2003), at Shambat area

Average counts / 50 leaves Month Um Shidaida Taroob Adana July, 2000 19.00 - - Aug. 3.00 - - Sept. 13.00 - - Oct. - - - Nov. - - - Dece. 10.00 - - Jan., 2001 0.00 - - Feb. 0.00 - - Mar. 0.50 - - April 0.00 - - May 0.00 - - April, 2002 - 60.67 - May - 25.40 - June. 2.75 53.00 21.00 July 5.00 81.75 51.11 Aug. 142.00 0.00 17.67 Sept. 151.34 5.00 47.67 Oct. 60.00 4.00 0.00 Nov. 0.00 9.00 0.00 Dec. 38.50 6.33 4.00 Jan. 2003 - 15.67 0.00 Feb. - 9.00 - March - 0.00 - (-) no count was made

156 Table 10. Comparisons of the mean counts of different stages (a, b and c) of Urentius euonymus, between upper and lower surfaces of the pigeon pea leaves, during the different seasons (2001 - 2002), at Shambat.

(a): Adults / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 9.79 ± 2.21 ns 6.50 ± 0.60 ** 1.92 ± 0.29

Lower 4.71 ± 2.92 1.11 ± 0.44 3.84 ± 0.63 ns

(b): Nymphs / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 18.13 ± 4.94 22.50 ± 8.95 7.50 ± 2.58

Lower 52.00 ± 24.61 ns 22.83 ± 13.60 ns 26.17 ± 4.29 ns

(c): Adults + nymphs / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E X ± S.E X ± S.E

Upper 27.92 ± 7.05 29.00 ± 9.03 ns 9.42 ± 2.47

Lower 56.71 ± 27.48 ns 23.95 ± 14.03 30.00 ± 4.05 ns

** = Highly significant difference ( P≥ 0.01) ns = Non significant difference. Table 11. Comparisons of the mean counts of different stages (a, b and c) of Urentius euonymus, between upper and lower

157 surfaces of "Hambouk" (Abutilon spp.) leaves, during the different seasons (2001 - 2002), at Shambat area.

(a): Adults / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 44.85 ± 14.57 ns 28.10 ± 6.30 33.97 ± 7.30*

Lower 2.27 ± 0.37 29.30 ± 4.52 ns 8.26 ± 4.13

(b): Nymphs / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E. X ± S.E. X ± S.E.

Upper 170.69 ± 54.50ns 51.20 ± 20.41 179.90 ± 24.85 *

Lower 1.51 ± 0.87 84.90 ± 24.99 ns 10.72 ± 2.47

(c): Adults + nymphs / 50 leaves

Season Summer Autumn Winter

Side of leaves X ± S.E X ± S.E X ± S.E

Upper 215.54 ± 69.03ns 79.30 ± 25.97 213.87 ± 31.20 *

Lower 3.79 ± 0.99 114.20 ± 25.33 * 18.97 ± 6.45

** = Highly significant difference ( P≥ 0.01) * = Significant difference ( P≥ 0.05) ns = Non significant difference.

158

Table 12. The weekly mean counts of Galeatus scrophicus (Adults + nypmphs / 50 leaves) on two varieties of sunflower grown during two seasons, at Shambat.

Winter, 2001/2002 Autumn, 2003 Date HYSUN33* HSHA9* Date HYSUN33* HSHA9* 26.10.2001 0.00 0.67 20.8.2003 0.00 0.00 2.11 0.67 0.00 27.8. 0.00 4.00 9.11 0.00 0.33 3.9. 0.00 2.00 16.11 0.00 0.67 10.9. 0.33 2.00 23.11 1.00 0.67 17.9. 0.67 6.00 30.11 0.67 3.33 24.9. 5.67 16.67 7.12 24.67 21.33 1.10. 1.33 21.00 14.12 23.33 14.67 8.10 1.00 35.00 21.12. 26.00 26.67 15.10 1.67 8.67 29.12. 15.33 49.33 - 5.1.2002 23.00 68.33 - 12.1. 65.67 93.00 - 20.1. 86.33 91.00 - Total 266.67 370.00 Total 10.67 95.34

* HYSUN 33 and HSHA9 (sunflower varieties) . (-) no count was made

159 When the two varieties were compared, the population of insects was found

to be relatively higher on HSHA 9 than on the other variety (Table 13). The mean

numbers of the different stages of the pest counted during December-January, on

the two sides of the leaves were also compared for each variety as explained in

Table (14). The means of adults, nymphs or adults + nymphs were all higher on the

upper sides than on the lower sides of the leaves of each variety. The means

separation showed no significant differences between the two sides of leaves on the

two varieties.

Counts of Galeatus scrophicus were also done during the surveys on two of the detected alternative wild host plants, “Rantouk” (Xanthium brasilicum) and “Moleita” (Lactuca taraxifolia). Table (15) shows the monthly mean counts of the pest on the two hosts during the winter season (October-March, 2002/2003). Similarly, the pest numbers were found increasing progressively as the temperatures decreasing from October (2002) up to the March (2003). However, it was observed that the count of insects on “Rantouk” dropped suddenly from January onwards, coinciding with severe powdery mildews infestation on this host. Nevertheless, this weed plant was harbouring the highest population of G. scrophicus during other periods compared with the other hosts. Among the newly encountered lace bug species a preliminary population assessment was performed for “Rehan”, “Sidir”, “Guddeim” and “Andrab” lace bugs during November-October (2002-2003) period (Table 16). The mean monthly counts of these pests on their respective host plants indicated that they were all abundant during the winter months (November-April; Table 16). The adults of these pests were generally

160 found on both surfaces of their hosts leaves. However, breeding and, hence, aggregation of nymphs of each species seemed to be found mainly on the lower surfaces of leaves. Moreover, in addition to their

Table 13. Comparisons of the mean seasonal counts of Galeatus scrophicus (adults + nymphs / 50 leaves), on two varieties of sunflower, during October – January (2001/2002), at Shambat.

Crop variety Mean Counts

X ± S.E.

HYSUN 33 20.51 ± 0.98

HSHA 9 28.46 ± 5.22 ns ns = Non significant difference.

161 162

Table 15. The monthly mean counts of Galeatus scrophicus on "Rantouk" (Xanthium brasilicum) and "Moleita" (Lactuca taraxifolia), surveyed during winter season (2002/2003) at Shambat area

Average counts / 50 leaves Month Rantouk Moleita Octob., 2002 82.75 21.50 Nov. 143.00 10.80 Dec. 241.75 5.00 Jan., 2003 48.50 9.60 Feb. - 90.00 March - 120.00

(-) no count was made

163

Table 16. The monthly mean counts of different lace bug species on their respective hostplants – "Rehan" (Ocimum basilicum), "Sidir" (Ziziphus spina-christi), "Guddeim" (Grewia tenax) and "Andrab" (Cordia sinensis), – Surveyed during different months (2002 – 2003) at Shambat area.

Months Average counts / 50 leaves

Rehan Sidir Guddeim Andrab

Nov., 2002 70.00 - 160.00 40.00 Dece. 105.00 - 150.67 62.00 Jan., 2003 109.00 - 133.00 51.00 Feb. 103.67 - 231.00 45.00 March 111.00 41.00 195.50 30.00 April 88.00 32.00 8.00 17.00 May - 16.00 2.00 20.00 June - 3.00 0.50 9.00 July - 1.00 1.00 2.00 Aug. - 2.00 1.67 3.33 Sep. - 10.00 1.75 2.00 Oct. - - 2.33 4.00

(-) no count was made

164 presence on leaves of the different plant heights of “Rehan” (Ocimum basilicum), high populations of "Rehan" lace bug were observed on the leaves and bracts of branches terminals, as well as on sepals and bases of flowers of this host.

4.4 Damage inflicted by the different lace bug species Lace bugs mainly affect their hosts directly through depletion of plant nutrients. Affected parts became yellowish then soon turned to whitish in colour. It was observed that, when adults invading a crop for the first time, their damage appears as numerous whitish spots which became visible in certain places of leaves (e.g. Pl. 3 left), according to species of the lace bugs. In such places, lace bugs seem to lay their eggs. Upon hatching, nymphs always feed in groups, and were never found singly as sometimes seen in adults. Therefore, nymphal damage appears firstly as small white batches, increases gradually in sizes as the nymphs develop. In severe infestation the whole leaf turns to whitish skeletonized translucent sheet, dries up and drop and, hence, the whole plant may be ruined (Pl. 2). The nymphs are the most destructive stage of the lace bugs, and they mostly do not move from one leaf to another, unless the first one has been completely exhausted. The above characteristics of damage are typical to the all reported insect pest species, but according to places on leaves where damage occur, two categories of lace bugs were recognized. The first one, generally starting their damage at the leaf bases between the main veins, and then the damage proceeds gradually towards the leaf terminals. This pattern was happened exactly in the cases of Urentius hystricellus (Pl. 4) and Urentius euonymus (Pls. 3 and 5), and to some extent in “Sidir” lace bug and “Guddeim” lace bug (Pl. 6).

165

Plate 3. Progress of damage (from left to right) inflicted by Urentius euonymus on leaves of Cajanus cajan

79

Plate 4. Progress of damage (from left to right) inflicted by Urentius hystricellus on leaves of Solanum melongena (upper) and Solanum dubium (lower)

b

Plate 5. Progress of damage (from left to right) inflicted by Urentius euonymus on leaves of Abutilon sp. (upper) and Rhynchosia memnonia (lower)

c

Plate 6. Progress of damage (from left to right) by "sidir" Iace bug (upper) and "Guddeim" Iace bug (lower).

d On the contrary, the other group of lace bugs were found to start their feeding damage at the leaf marginals, then the damage extends progressively inwards. This habit has been clearly shown by Galeatus scrophicus (Pl. 7), “Andrab” lace bug and “Rehan” lace bug (Pl. 8). Damage of the latter group was found to occur in much cases on the upper surfaces of plant leaves, while the opposite was true for the first group. Moreover, a part from the symptoms of feedings mentioned above, some damaged leaves especially on sunflower, "Andrab" (Cordia sinensis) and "Rehan" (Ocimum basilicum) hosts, usually turn dark brown to blackish in colour , which look as if they were burned. However, each pest species in the two categories, was more or less exhibited the same kind of leaf damage on its different host plants. Lastly, it can be said that all the recognized lace bug species were exploiting their host plant(s) recorded both for feeding and breeding purposes, since symptoms of damage together with the population of adults and nymphs of each species (except “Adana” lace bug where only adults were recorded in small numbers) were already detected on these hosts.

4.5. Duration of the pre-adult stages of some important species on their major host plants Certain biological aspects including pre-oviposition and incubation periods together with the duration of nymphal stages were studied for three important lace bug species, in the laboratory. These species included: Urentius hystricellus, U. euonymus and Galeatus scrophicus, where each one was reared on two of its major host plants (cultivated and wild). All the experiments were conducted during autumn (August –

e

Plate 7. Pattern of damage inflicted by Galeatus scrophicus on leaves of Lactuca taraxifolia (starts from leaf margin inwards).

f

Plate 8. Progress of damage (from left to right) on leaves induced by “Andrab” lace bug (upper) and “Rehan” lace bug (lower) (starts from leaf margin inwards).

g November, 2001) and repeated during winter season (January – February, 2002). The eggplant lace bug (U. hystricellus) was studied on eggplant (Solanum melongena), the lonely cultivated host, and “Gubbein” (Solanum dubium), the solely wild host plant detected in the area. The results are depicted in Table (17). Firstly it should be stated that pre-oviposition and incubation periods were followed only on eggplant seedlings, due to failure in growing seedlings of “Gubbein”. The pre-oviposition time on eggplant took shorter period in autumn (av. 1.5 + 0.24 days) when compared with winter season (3.70 + 0.20). However, the means recorded for incubation period and total nymphal duration on eggplant were 4.93 + 0.10 and 7.50 + 0.15 days in autumn, and 11.87 + 0.13 and 14.53 + 0.28 days in winter season, respectively. The percentages of insects died during the two experiments were relatively higher on eggplant (14.29% in autumn, and 12.00% in winter) than on wild “Gubbein” host (10.00% and 6.67%, in the two seasons, respectively). The results obtained from biological studies of U. euonymus on pigeon pea (Cajanus cajan) and “Hambouk” (Abutilon sp.) host plants are shown in Table (18). The durations of all pre-imaginal stages of this pest were longer than those of U. hystricellus. The pre-oviposition period was nearly similar on the two host plants, giving an average of 1.60 + 0.24 and 4.00+ 0.16 days on pigeon pea, during autumn and winter seasons, respectively. The incubation period on pigeon pea was slightly short during autumn (av. 5.67 + 0.06 days) and long during

h winter (13.40 + 0.18 days), when compared with those obtained on “Hambouk” host. The same contraversial results on the two hosts between the two seasons, as

i

seen for the incubation period, were also shown when nymphal duration were concerned. However, the average durations of the total nymphal stages were 7.95 + 0.14 and 16.21 + 0.33 days in autumn and winter seasons, respectively. Similarly, the mortality percent was low on pigeon pea (17.54%) when compared with “Hambouk” (28.36%), during autumn, while nearly similar results were obtained on the two hosts (13.64% and 13.33% on pigeon pea and “Hambouk”, respectively) during winter season. Regarding Galeatus scrophicus the life times for the indicated biological aspects

j were done on sunflower (Helianthus annus) and “Moleita” (Lactuca sp.) host plants during the two seasons (Table 19). However, due to lack of “Moleita” seedlings, the pre- oviposition and incubation periods were performed only on sunflower. They accounted on an average 2.60 + 0.24 and 6.37 + 0.11 days in autumn, and 4.80 + 0.20 and 10.77 + 0.22 days in winter season, respectively. The nymphal durations were nearly similar on the two host plants. On sunflower, the averages of the total nymphal periods were 7.75 + 0.20 days in autumn and 14.50 + 0.30 days in winter season. According to the previous biological studies the three investigated lace bug species acquired five nymphal instars differing in their duration periods. However, in all species the last nymphal (5th) instar showed the longest duration, followed by the first instar, while the rest three intermediate stages showed the lowest durations in each season. 4.6 Natural enemies of lace bugs and their seasonal abundance In the course of studying the natural enemies of the lace bugs, parasites of Urentius hystricellus and U. euonymus were inspected through seasonal samplings of nymphal stages. The results showed no

k

parasites for the two pest species. On the other hand, the predators of the lace bugs were studied during the periodical surveys and counts done on planted experiments (eggplant, pigeon pea and sunflower) and natural vegetation (those harbouring lace bugs), as well as on other certain important cultivated crops (not harbouring lace bugs) such as “Berseem” (Medicago sativa), forage sorghum (Sorghum bicolor) and maize (Zea mays). Such counts on hosts and non hosts plants of the lace bugs could help in understanding prey preference of different predators between lace bugs and other arthropod insects. Potentially important groups of predatory species found preying on lace bugs were reported during this study. They include insects and spiders which

l fall under two classes, Insecta and Arachnida, respectively, of the phylum Arthropoda. All the detected species were considered as generalized predators feeding besides lace bugs on other different arthropod species. However, the followings are the important predatory insects (a) and spiders (b) found prevalent in the area: (a) Insect predators • Family: Coccinellidae - Hippodamia (= Adonia) variegata (Goeze) (Pl. 9) - Cheilomenes (= Cydonia) propinqua vicina Muls (Pl. 10) - Scymnus spp. (Pl. 11 a - c) - Coccinella undecimpunctata L. (Pl. 11 d) • Family: Chrysopidae - Chrysoperla pudica (C. carnea) (Pl.12) • Family: Syrphidae - Xanthogramma (= Ischiodon) spp. (Pl.13 c ,d) • Family: Mantidae - Mantis spp. (Pl. 13 a, b)

m

Plate 9. Different stages of Hippodamia variegata on different host plants; a) Adults on alfalfa b) Egg batch on okra c) Larva on eggplant d) Larvae + prepupae on sorghum e) Pupa on eggplant f)Pupa on alfalfa

n

Plate 10. Different stages of Cheilomenes propinqua vicina on different hosts; a) Mating adults on eggplant b) Last larval stage on eggplant c) Pupae on eggplant d) Pupa on Datura sp.

o

Plate 11. Different coccinellid species on different host plants; a) Scymnus adult on Abutilon sp. b) Scymnus adult on Calotropes sp. c) Scymnus larvae on Calotropes fruit d) Adults of Coccinella undecimpunctata on okra.

p

Plate 12. Different stages of Chrysoperla pudica on different host plants; a) Adult on okra b) Egg on alfalfa c) Larva on okra d) Pupa on eggplant.

q

Plate 13. Different predatory insects on different host plants; a) Mantid nymph on eggplant b) Mantid eggs (ootheca) on Acacia sp. c) Syrphid adult on alfalfa d) Syrphid larva and pupa on sorghum.

r (b) Spiders • Different species among cobweb weavers (Pl. 14 a, b • Family: Salticidae – different species (Pl. 14 c) • Family: Thomisidae (Pl.14 d)

Coccinellid insects seem to be inefficient as predators of lace bugs, although larvae of Hippodamia were observed feeding on a nymphal-stage of such bugs in the field. Similarly, more than one species of syrphid fly were recorded in the field, but no one has ever been found preying upon lace bugs. However, the coccinellid and syrphid predators appear to rely more on other insects like aphids, than on lace bugs in their feeding preference. Therefore, their presence on certain host plants was found to be more synchronized with those preferred insects. The coccinellids were, hence, detected on various vegetation like field crops, vegetables, medicinal plants, horticultural crops and on various wild plants. Members of at least two species of mantids were sometimes found on eggplant and some of the surveyed hosts in the field, but their numbers were so low than to be assessed as biocontrol agent for the lace bugs. Eggs of mantids were generally found stuck to branches of trees and bushes away from the ground level and were never found on weeds and small plants like vegetable crops. The ootheca of eggs were encountered during the surveys on Acacia spp., Balanitis sp., Ziziphus spp., Cajanus

s cajan and large Abutilon sp. From there the nymphs seem to disperse on weeds and other crops found in the field. On the other hand, Chrysoperla sp. and spiders were the most prevalent predators associated with lace bugs in the field. They were always observed on most surveyed plants preying on different species of lace bugs. Therefore, a preliminary test of feeding capacity of these predators (chrysopid and spider species) including some coccinellid

t

Plate 14. Different spiders on different host plants; a) Species of cobweb weavers prevailing on eggplant b) Weaver species guarding its eggs mass on maize c) Salticid species catched on eggplant d) Thomisid species on eggplant.

u species, on the nymphal stages of U. hystricellus, was conducted in the laboratory at Shambat. The results shown in Table (20) indicated that the 4th instar larvae of Chrysoperla sp. were the most efficient predators, voraciously consumed an average of 196.33 + 17.64 nymphs per day. The different spiders tested (web weaver, thomisid and salticid species) came next in order killing an average insects ranging from 101.00 + 5.03 to 180.67 + 14.53 nymphs / day. However, coccinellids utilized a far less numbers of tingid nymphs (25.33 + 7.31 – 51.67 + 2.14) than the previous predators. The seasonality of predators on eggplant, in its weekly trends are arranged in Table (21). Table (22) showed the monthly mean counts (per 50 leaves of 10 plants/plot) during the different seasons. The average numbers of predators were generally higher in winter time (February – March) than in the other seasons. However, spiders were the dominant predators on eggplant during summer and autumn seasons constituted about 53.91% and 64.80% of all predators, respectively. Chrysoperla sp. came next in order followed by coccinellids. On the other hand, during winter season chrysopids were the most prevalent (41.96%) followed by coccinellids (24.08%) and then spiders (21.09%; Table 23). Ranking of the different species of spiders detected during the various seasons on eggplant started with the cobweb weavers- varioius species (65.50%), then the Salticidae – various species (20.50%) and lastly the Thomisidae (14.00%) (Pl. 14 d). The first group of spiders were generally observed weaving their nets

v around the colonies of lace bug nymphs on the undersides of eggplant leaves (Pl. 15 a). Regarding the wild host plant ”Gubbein” (Solanum dubium), the same predators recorded on eggplant were found on this host. The weekly population means of total predators also follow the same trends, as for the

w

Table 20. Preliminary test of feeding capacity of some predators on the nymphal stages of Urentius hystricellus in the laboratory at Shambat (March – April/2001).

Insects consumed /day Predators X ± S.E

Chrysoperla sp. (4th. instar larvae) 196.33 ± 17.64

Hippodamia variegata (adults) 30.00 ± 9.54

Cheilomenes vicina (adults) 25.33 ± 7.31

Coccinella undecimpunctata (4th instar larvae) 51.67 ± 2.14

Spiders (species of cobweb weavers) 180.67 ± 14.53

Spiders (thomisid) 139.00 ± 7.09

Spiders (salticid) 101.00 ± 5.03

x

Table 21. The weekly population means (per 50 leaves) of all predators encountered on eggplant during the different growing seasons (1999 – 2002), at Shambat.

Growing seasons 1999 / 2000 2000 2000/2001 2001 2001/2002 Date Mean Date Mean Date Mea Date Mean Date Mean n 15.12.9 0.67 27.4.0 0.33 16.12. 0.33 6.7.0 6.00 17.12.0 0.67 9 1.00 0 1.00 00 1.00 1 3.67 1 1.67 22.12 1.67 4.5 2.33 23.12 1.67 13.7 7.33 24.12 11.00 29.12 1.33 11.5 2.33 30.12 1.33 20.7 8.33 31.12 6.67 5.1.00 2.00 18.5 1.67 6.1.01 1.33 27.7 5.67 7.1.02 4.00 12.1 2.00 25.5 2.67 13.1 7.33 3.8 5.00 14.1 4.67 19.1 2.33 1.6 4.67 20.1 1.33 10.8 3.67 21.1 2.67 26.1 3.67 8.6 4.33 27.1 14.33 17.8 3.00 28.1 6.67 2.2 7.00 15.6 7.33 3.2 2.33 24.8 2.67 4.2 7.67 9.2 6.00 22.6 14.33 10.2 1.33 31.8 2.33 11.2 11.33 16.2 6.33 29.6 0.67 17.2 3.67 7.9 2.67 18.2 9.33 23.2 5.33 6.7 1.00 24.2 3.67 14.9 2.67 25.2 8.67 2.3 9.33 13.7 1.00 3.3 5.33 21.9 3.67 4.3 8.67 9.3 5.33 20.7 0.67 10.3 7.00 28.9 4.00 11.3 3.67 16.3 3.00 27.7 2.00 17.3 5.00 5.10 3.67 18.3 8.33 23.3 3.00 3.8 24.3 2.33 12.10 3.67 25.3 4.67 30.3 9.33 31.3 2.67 19.10 3.67 1.4 5.00 6.4 9.00 7.4 2.33 26.10 4.67 8.4 2.33 13.4 14.4 2.67 2.11 1.67 15.4 21.4 3.00 9.11 3.33 28.4 4.67 16.11 2.33 5.5 6.67 23.11 12.5 3.67 19.5

y

Table 22. The monthly mean counts (per 50 leaves) of predators encountered on eggplant, during different growing seasons (1999 – 2002), at Shambat.

Growing seasons 1999 / 2000 2000 2000 / 2001 2001 2001 / 2002 Mont Mea Month Mea Month Mea Mont Mea Month Mea h n n n h n n

Dec. 1.11 May, 1.83 Dec., 1.00 July,0 6.33 Dec., 4.45 99 00 00 1 01

1.92 6.67 2.83 Aug. 4.00 4.50 Jan. 00 June Jan., Jan., 02 01 5.75 1.07 5.42 Sept. 2.84 8.75 Feb. July, Feb. 00 Feb. 5.20 4.67 Oct. 3.75 7.34 March March. March 9.17 2.67 Nov. , 3.00 4.00 April,0 2001 April 0 April 02 5.00

May, 01

z

Table 23. The relative percentage (%) of main predators encountered on eggplant, during different seasons (1999 – 2002), at Shambat.

Seasons Summer Autumn winter

Predators % % %

Chrysopids 22.62 12.97 41.96

Coccinellids 15.65 18.53 24.08

Spiders * 53.91 64.80 21.09

Others Θ 7.82 3.70 12.87

* Species of spiders were mainly members of cobweb weavers-different species (65.5%), Salticidae (20.5%) and Thomisidae (14.0%). Θ Mainly syrphids, but rarely mantids.

aa

Plate 15. Different net traps of different weaver spiders on leaves of; a) Eggplant b) Pigeon pea c) Abutilon sp. d) Alfalfa (eggs sac)

bb eggplant, during the three consecutive years of study (Table 24). The highest populations occurred in winter (Fig. 27) and the spiders were dominant during the three seasons (96.46%, 95.79% and 56.00% for summer, autumn and winter, respectively), followed by the chrysopids and lastly the coccinellids (Table 25). Tables (26) and (27) present the weekly mean counts of predators encountered on pigeon pea (Cajanus cajan) and “Hambouk” (Abutilon sp.) during the three years of study. As depicted in Figs. (28) and (29), the populations of total predators were relatively higher in February - June period and October month, than in the other periods. The population trends of these predators were found to be more synchronized with those of their preys (Figs.25 and 26). The relative percentage of such predators on pigeon pea and “Hambouk” during the different seasons are presented in Tables (28) and (29), respectively. During summer and autumn > 83% of the encountered predators on the two hosts were spiders, while chrysopids came next in order, but their numbers were far less than those of the first group. Again species of cobweb weavers were dominant on the two hosts (> 80%; Tables 28 and 29), with their net traps entangling lace bugs became familiar in the field (Pl. 15 b, c). In winter the number of spiders (63.38%) was double that of the chrysopids (30.99%) in case of pigeon pea, while the opposite was true for “Hambouk” host (Tables 28 and 29). No regular population census of predators were made on the other plants

cc recorded as hosts for the lace bugs, but continuous observational surveys proved the superiority of spiders and chrysopids over the other kinds of predators. Various species of spiders among cobweb weavers, Salticidae and Thomisidae, as well as larvae and stalked eggs of Chrysoperla sp. were encountered in appreciable numbers associated

Table 24. The weekly population means (per 50 leaves) of predators encountered on "Gubbein" (Solanum dubium), during three consecutive years (2000 – 2002) of surveys in Shambat area.

Year 2000 2001 2002 Year 2000 2001 2002 Mean Mean Mean Mean Mean Mean Date Date 2.Jan. 6.00 7.00 5.00 3.7 2.00 2.33 2.00 9.1 5.00 8.33 6.33 10.7 0.67 0.67 1.33 16.1 5.33 5.33 4.00 17.7 1.33 1.67 1.67 23.1 4.67 5.00 3.33 24.7 1.67 1.67 1.00 30.1 1.67 5.00 2.67 31.7 1.33 2.00 4.00 6.2 2.00 7.33 3.00 7.8 1.00 2.33 1.67 13.2 6.00 2.67 3.33 14.8 1.33 1.67 1.00 20.2 4.00 2.00 4.00 21.8 1.00 1.00 0.33 27.2 3.67 2.33 5.00 28.8 1.67 1.33 2.00 6.3 3.33 2.00 5.33 4.9 1.33 1.67 1.67 13.3 4.33 2.33 6.33 11.9 1.33 1.00 1.00 20.3 4.67 4.00 6.33 18.9 1.67 2.00 2.33 27.3 0.67 1.67 6.00 25.9 1.33 1.33 4.67 3.4 3.67 2.00 8.67 2.10 2.00 1.33 2.33 10.4 5.00 0.33 6.00 9.10 1.33 1.67 3.33 17.4 6.00 1.33 7.67 16.10 1.67 2.00 2.00 24.4 5.33 1.33 1.67 23.10 2.00 1.67 1.67 1.5 3.33 1.67 2.33 30.10 2.00 1.33 2.00 8.5 2.00 1.00 4.33 6.11 2.33 2.00 3.67 15.5 1.00 0.00 5.00 13.11 3.33 1.67 2.67 22.5 0.67 0.33 1.67 20.11 3.00 2.00 2.00 29.5 0.67 0.33 1.00 27.11 3.00 1.67 3.00 5.6 2.00 0.00 1.67 4.12 4.00 1.00 3.33

dd 12.6 1.00 0.33 2.00 11.12 3.33 1.67 3.67 19.6 1.67 0.67 1.67 18.12 2.00 1.00 4.00 26.6 1.67 1.33 2.33 25.12 6.67 3.00 4.00

ee ff

Table 25. The relative percentage (%) of main predators encountered on "Gubbein" (Solanum dubium), during the different seasons (2000 – 2002), at Shambat area.

Seasons Summer Autumn winter

Predators % % %

Chrysopids 1.77 1.05 29.33

Coccinellids 1.77 2.11 12.00

Spiders * 96.46 95.79 56.00

Others Θ 0.00 1.05 2.67

* Species of spiders were members of cobweb weavers-different species (97.28%), Salticidae (2.17%) and Thomisidae (0.55%). Θ Syrphids and mantids.

gg

Table 26. The weekly population means (per 50 leaves) of predators encountered on pigeon pea, during the different seasons (2000 – 2002), at Shambat.

Year 2000 2001 2002 Year 2000 2001 2002 Mean Mean Mean Mean Mean Mean Date Date 1.Jan. 0.33 0.67 0.00 23.7 1.33 1.00 1.67 8.1 0.00 1.33 0.00 30.7 1.67 1.33 1.67 15.1 1.00 0.33 0.67 6.8 1.33 1.00 1.00 22.1 0.67 0.33 0.00 13.8 167 1.00 0.67 29.1 2.67 1.67 0.67 20.8 1.00 1.00 2.00 5.2 0.67 2.00 1.33 27.8 2.00 1.33 1.33 12.2 1.00 2.67 1.00 3.9 0.67 1.67 0.67 19.2 2.33 3.33 1.67 10.9 2.00 0.67 1.00 26.2 3.00 2.67 3.00 17.9 2.00 1.00 1.33 5.3 2.67 1.33 2.00 24.9 2.33 1.00 1.33 12.3 2.67 2.67 1.00 1.10 2.67 2.67 1.33 19.3 2.33 1.00 1.67 8.10 2.00 2.00 1.33 26.3 3.33 2.33 2.67 15.10 2.33 0.67 1.67 2.4 1.67 2.67 1.00 22.10 2.00 1.33 1.67 9.4 2.33 3.00 1.00 29.10 2.67 1.67 1.67 16.4 2.33 1.33 0.33 5.11 1.00 0.67 1.00 23.4 1.33 2.00 0.33 12.11 1.00 0.33 0.67 30.4 1.33 2.67 0.33 19.11 1.33 0.67 0.33 7.5 0.67 4.33 0.67 26.11 0.67 0.67 2.00 14.5 1.33 3.33 0.33 3.12 0.67 1.00 0.67 21.5 2.33 2.33 0.67 10.12 0.67 1.33 1.67 28.5 2.67 3.00 1.00 17.12 1.33 0.67 1.33 4.6 2.33 2.33 1.00 24.12 1.33 0.67 1.00 11.6 3.00 3.33 0.33 31.12 0.67 0.67 1.33 18.6 1.67 2.00 2.67 25.6 2.33 3.00 2.00 2.7 1.67 2.33 2.33 9.7 2.00 2.67 0.67 16.7 1.67 1.33 1.33

hh

Table 27. The weekly population means (per 50 leaves) of predators encountered on "Hambouk" (Abutilon spp.), during three consecutive years (2000 – 2002), of surveys in Shambat area. Year 2000 2001 2002 Year 2000 2001 2002 Mean Mean Mean Mean Mean Mean Date Date 2.Jan 0.33 0.67 3.00 24.7 1.67 1.33 1.33 9.1 0.33 0.33 0.67 31.7 1.33 1.33 1.00 16.1 1.00 0.67 0.67 7.8 1.67 1.00 0.67 23.1 0.67 0.67 1.00 14.8 2.00 1.33 1.00 30.1 0.33 1.00 1.00 21.8 1.33 1.00 0.67 6.2 0.67 0.67 4.00 28.8 1.67 1.33 1.33 13.2 0.67 1.00 1.33 4.9 1.33 1.00 0.33 20.2 1.00 0.67 1.67 11.9 1.33 1.00 1.67 27.2 0.33 1.33 1.33 18.9 1.00 1.33 1.00 6.3 0.33 2.33 1.00 25.9 2.00 1.33 0.67 13.3 1.33 2.00 1.67 2.10 2.33 1.00 1.67 20.3 1.33 3.33 1.67 9.10 2.00 2.67 2.00 27.3 1.00 5.33 1.67 16.10 2.00 2.33 2.00 3.4 2.00 3.67 2.00 23.10 2.33 2.67 2.33 10.4 2.00 3.00 1.67 30.10 1.67 2.33 1.67 17.4 2.33 3.33 2.00 6.11 1.67 2.33 1.33 24.4 1.67 2.00 1.33 13.11 1.33 2.67 1.00 1.5 2.00 2.33 2.00 20.11 1.67 2.33 1.00 8.5 2.33 1.67 1.67 27.11 2.00 2.00 0.33 15.5 1.67 1.00 2.33 4.12 1.67 2.33 0.67 22.5 2.00 1.33 2.67 11.12 1.67 2.00 1.00 29.5 2.00 1.67 1.00 18.12 1.00 0.33 1.33 5.6 2.00 1.67 1.33 25.12 2.00 1.00 1.33 12.6 2.67 2.00 1.33 19.6 2.33 1.67 1.67 26.6 2.00 2.33 0.67 3.7 2.00 1.00 1.00 10.7 1.33 1.00 0.67 17.7 1.67 1.33 1.00

ii

jj kk

Table 28. The relative percentage (%) of main predators encountered on pigeon pea, during the different seasons (2000 – 2002), at Shambat.

Seasons Summer Autumn winter

Predators % % %

Chrysopids 2.00 7.14 30.99

Coccinellids 2.00 3.57 4.22

Spiders * 96.00 89.29 63.38

Others Θ 0.00 0.00 1.41

* Species of spiders were mainly cobweb weavers (86.67%), Salticidae (8.00%) and Thomisidae (5.33%). Θ Mainly syrphids.

ll

Table 29. The relative percentage (%) of main predators encountered on "Hambouk" (Abutilon spp.) during different seasons (2000 – 2002), at Shambat area.

Seasons Summer Autumn winter

Predators % % %

Chrysopids 8.06 14.28 50.53

Coccinellids 3.23 1.80 18.95

Spiders * 88.71 83.92 29.47

Others 0.00 0.00 1.05

* Species of spiders were members of cobweb weavers- different species (90%) and Salticidae (10%).

mm with lace bugs on most host plants even on large trees like “Sidir” (Ziziphus sp.) and “Guddeim” (Grewia tenax). As mentioned earlier all the encountered entomophagous species were general predators feeding besides lace bugs on various arthropod species. However, some preferences were found when different preys were available. Therefore, the occurrence of all recorded bioagents were evaluated on some major crops grown in the area which are not host plants for the lace bugs. These crops included “Berseem” (Medicago sativa), forage sorghum – “Abu 70” (Sorghum bicolor) and maize crop (Zea mays). On “Berseem”, weekly surveys of all predators were carried out during two years (2001 and 2002). The results are explained in Table (30) as monthly mean counts of each group of predators, whereas, their collective means are depicted in Fig. (30). The coccinellid species found on this crop were Hippodamia variegata, Cheilomenes propinqua vicina, Coccinella undecimpunctata and Scymnus spp., while the non coccinellids include mainly Chrysoperla sp. plus different species of spiders (Pls.9 – 14). Hippodamia sp. was the dominant coccinellid among the detected predators and accounted for more than 70% of the total predators on “Berseem” during the two years of surveys. In contrast to their previous abundance on lace bug host plants, the coccinellids on “Berseem” were peaked in June (13.58 insects/1m2) and September (21.83 insects) during the year 2001, and in June (9.75 /1m2) during 2002 (Table 30). The Chrysoperla sp. and spiders were relatively

nn small in numbers compared with the coccinellids on this crop.

2001 2002 Predator Month Cocc. Chry. Spid. Others Total Cocc. Chry. Spid. Others Total Table 30. The monthly mean counts (per 1m2 / plot) of different predators on January 4.73 0.33 0.13 1.20 6.39 4.33 0.47 0.13 1.13 6.06 Medicago February 6.67 0.42 0.50 1.08 8.67 7.50 1.33 0.17 0.50 9.50 sativa, during March 8.08 0.08 0.17 0.33 8.66 7.25 0.83 0.58 0.08 8.74 two years (2001 April 9.41 1.00 0.67 0.00 11.08 4.33 0.50 0.25 0.25 5.33 – 2002) of May 10.73 0.13 0.40 0.00 11.26 5.80 1.07 0.50 0.27 7.64 surveys June 13.58 0.34 0.58 0.17 14.67 9.75 0.50 0.58 0.17 11.00 July 3.00 3.00 0.27 0.00 6.27 3.33 0.07 0.20 0.20 3.80 Aughust 2.41 0.17 0.75 0.00 3.33 1.50 0.67 0.33 0.00 2.50 September 21.83 0.00 3.00 0.25 25.08 3.92 0.17 0.59 0.00 4.68 October 6.67 0.13 2.80 0.00 9.60 4.20 0.07 0.60 0.00 4.87 November 5.67 0.17 1.25 0.08 7.17 2.00 0.25 0.67 0.17 3.09 Dcember 3.67 0.58 0.08 0.58 4.91 0.83 0.25 0.25 0.50 1.83 • Cocc. = Coccinellids, Chry. = Chrysopids and Spid. = Spiders in Shambat area.

b

c d The egg masses of Coccinellidae, especially Hippodamia sp. were observed generally laid on the undersides of the lower leaves of plant canopy. The larvae and adults were found wandering about at different plant heights, while on the other extreme, the pupae were always fixed to the upper surfaces of leaves, that found on the upper third of plant heights, in a way looked as if they were exposed to the sun light (Pl. 9f). Similarly, the eggs sacs of spiders were also found on the upper surfaces of top leaves (Pl. 15d). The weekly surveys of predators on “Abu 70” (Sorghum bicolor) resulted in the same groups of predators found on “Berseem”. The coccinellid and chrysopid species were the same, but the dominant species of spiders were different between the two crops (Pl. 14b showed the species dominant on “Abu 70”). However, the results of weekly counts on “Abu 70” crop were summarized as monthly means of each group of predators, as shown in Table (31). The collective means of total predators are depicted in Fig. (31). Winter season (January – April) and August – October period (Table 31 and Fig. 31) witnessed the highest population of natural enemies. The coccinellid predators were also dominant on this crop (71.22% and 61.13% during 2001 and 2002, respectively), followed by the spiders (15.66% in 2001 and 18.53% in 2002) and lastly the Chrysoperla sp. (7.83% in 2001 and 14.73% in 2002) (all percetages calculated from Table 31). The coccinellid species during summer and autumn seasons were mainly confined to the leaf whorls of sorghum plants, where colonies of an species occurred, but after crop heading some adults were found inserted in heads feeding on pollen grains and probably on some small insects.

Table 31. The monthly mean counts (per 25 plants) of different predators on “ Abu 70” { Sorghum bicolor), during two years (2001 – 2002) of surveys in Shambat ar

b ea.

2001 2002 Predator Month Cocc. Chry. Spid. Others Total Cocc. Chry. Spid. Others Total January 30.13 1.80 0.80 5.80 38.53 5.67 2.60 0.80 2.60 11.67 February 25.92 0.92 1.34 0.50 28.68 12.42 3.67 1.25 0.67 18.01 March 14.17 6.00 1.00 0.00 21.17 12.50 1.42 1.17 0.83 15.92 April 5.16 0.92 0.75 0.00 6.83 8.58 2.00 1.25 0.17 12.00 May 1.33 0.27 2.07 0.00 3.67 2.60 2.73 1.47 0.20 7.00 June 2.67 0.67 2.34 0.08 5.76 1.00 0.42 1.59 0.00 3.01 July 2.34 0.00 1.47 0.00 3.81 0.66 0.20 0.67 0.00 1.53 Aughust 6.33 0.08 4.00 0.08 10.49 2.83 0.08 2.33 0.00 5.24 September 12.17 0.00 3.92 0.17 16.26 6.50 0.33 2.09 0.00 8.92 October 4.87 0.20 3.20 0.27 8.54 3.13 0.13 2.47 0.80 6.53 November 1.17 0.25 1.92 0.08 3.42 2.17 0.25 1.92 0.08 4.42 Dcember 0.17 0.59 0.59 0.92 2.27 1.08 0.42 0.92 0.08 2.50 • Cocc. = Coccinellids, Chry. = Chrysopids and Spid. = Spiders

b

c In comparison with forage sorghum, maize (Zea mays) crop was not much grown in Shambat area. Therefore, complete data were not available during the weekly counts of predators on this crop. The recorded counts are explained in Table (32) as monthly means of each group of predators. The occurrence and seasonal trends of these predators were more or less similar to what have been found on “Abu 70” crop. However, coccinellids and chrysopids were more abundant on maize than on forage sorghum (Table 32). As with regard to spiders, the dominant species recorded were similar to those found on “Abu 70” crop. Moreover, such dominant spiders on cereals as a whole (e. g. “Abu 70” and maize) were different from those prevailing on “Berseem”, eggplant, pigeon pea and other plants those harbouring lace bugs. This is especially true for the cobweb weaver species (Pl. 14), but members of Thomisidae and Salticidae were almost similar on all host plants.

2001 2002 Predator

Table 32. The monthly mean counts (per 25 plants) of different predators on Zea mays, during two years (2001 – 2002) of surveys in Shambat area.

Cocc. Chry. Spid. Others Total Cocc. Chry. Spid. Others Total January 0.00 0.00 3.00 0.00 3.00 0.33 5.07 0.60 0.33 6.33 February - - - - - 4.17 3.75 1.08 0.92 9.92

March 22.78 1.67 0.89 0.11 25.45 32.83 12.00 0.92 0.42 46.17

April 37.50 2.75 1.25 0.33 41.83 22.75 1.59 1.34 0.00 25.68 May 4.67 0.00 5.22 0.22 10.11 13.00 1.00 1.00 0.00 15.00 June ------July 13.00 0.50 1.00 0.00 14.50 - - - - - Aughust ------5. DISCUSSION September 29.51 2.34 1.34 0.34 33.53 - - - - - In its broadest October 21.60 2.60 1.27 1.20 26.67 - - - - - November 0.58 0.59 1.92 0.58 3.67 0.50 1.42 1.42 1.67 5.01 sense ecology of an Dcember 0.42 1.08 0.58 0.67 2.75 0.42 0.84 0.75 0.67 2.68 arthropod species may includes the habitat of an organism and its all activities and interactions with all components

• Cocc. = Coccinellids, Chry. = Chrysopids and Spid. = Spiders (biotic and abiotic) of the

• (-) = no count was made environment in which it lives. A very comprehensive definition of ecology was given by DE Long (1965), while studying leaf hoppers in North America, who

b stated that “ecology includes all the physical, chemical and biological factors in the media in which the organism lives”. In this context, lace bugs were investigated in their natural habitats in Khartoum State. Firstly it was aimed to recognize the species present and their main characteristics and behavioural features on their respective host plants. The seasonality of important species and their distribution within host plants and, hence, the characteristics of damage inflicted were closely followed under field conditions. Meanwhile, the duration of pre-imaginal stages of some species was followed on a cultivated and wild host plants in the laboratory. On the other hand, natural enemies of the detected lace bug species especially predators were surveyed and their presence and seasonal abundance were assessed on various cultivated and natural vegetation among hosts plants of the lace bugs and some important non hosts as well.

As shown in the results nine species of lace bugs were recorded, from which three species were already known, while six were new records. The reported species in the Sudan according to different literature are Urentius hystricellus Richter (Pollard, 1955; Drake and Ruhoff, 1965; Schmutterer, 1969; Guddoura, 1977, and Salih, 1991), Urentius euonymus Distant (Drake and Ruhoff, 1965, and Schmutterer, 1969) and Galeatus scrophicus Saunders (Drake and Ruhoff, 1965, and Guddoura, 1977). However, the six newly reported species were not yet identified and were named to their host plants. Hence, an attempt was made to identify some of these species to generic names based on an illustrations of the lace bugs made by Drake and Ruhoff (1965). According to this reference host plants were also taken into consideration. This helps in recognition of the species of lace bugs which have limited host range. Therefore, “Rehan” lace bug (Fig. 14) was suspected to be Cochlochila sp., as compared with Cochlochila bullita Stal, the only species reported infesting “Rehan”, Ocimum basilicum, in many African countries neighbouring to Sudan. Thaumamannia sp. (Fig. 16) was compared with an illustration of Thaumamannia manni Drake and Davis reported from Bolivia without mentioning of host plant, though, it is now recorded on “Adana”, Rhynchosia memnonia (Del.) DC. Finally, “Sidir” lace bug which collected from “Sidir” tree, Ziziphus spina-christa (L.) Desf., was suspected to be a Monosteira sp., as compared with Monosteira minutula Montandon, the only species reported on this tree in many African countries. However, no similar specimens were found as with regard to “Adana”, “Guddeim” and “Andrab” lace bugs which were detected on “Adana”, Rhynchosia memnonia, “Guddeim” Grewia tenax (Forsk.) Fiori and “Andrab”, Cordia sinensis L., host plants, respectively.

The six unidentified species were recorded each on a single host plant as mentioned above, but for the two Urentius spp. and G. scrophicus various hosts plants were found. The latter species was detected on seven host plants among the family Compositae including sunflower (Helianthus annuus L.), lettuce (Lactuca sativa L.), “Moleita” (Sonchus cornutus Hochst. ex Oliv. + Hiern), “Moleita” (Sonchus oleraceus L.), “Moleita” (Lactuca taraxifolia (Willd.) Schumach), “Rantouk” (Xanthium brasilicum Vell.) and “Rehan El Gadawil” (Pluchea diosecoridis (L.)) DC.). The first host plant (sunflower) was reviewed by several scientists in Sudan (Guddoura, 1977) and other parts of the world (e.g. Drake and Ruhoff, 1965; Rao and Thirumalachar, 1977, and Al Mallah, 1999), while the rest six were new records. However, Onder and Lodos (1983) had expected additional host plants among the family Compositae. In fact, all the detected hosts, except S. oleraceus, were found to sustain high population levels of G. scrophicus in fields at Shambat area. Only few

b infestation was observed one time on S. oleraceus showing minor damage on this host. Since, sunflower is not grown widely in the Khartoum State, these natural weeds represent an actual reservoir of the pest in this area.

Considering Urentius spp. eight host plants were recorded during the current study, as compared with five hosts stated in the literature. However, a lot of confusion has been found before between the two pest species and their host plants in this country. Some literature generally referred to both species on their different host plants, as Urentius hystricellus, while others put the two species as pests of the eggplant (e.g. Pollard, 1955). In fact, big differences were existed between U. hystricellus and U. euonymus according to the present study. The two species were found morphologically and biologically different, each has its own host range, and no single host was found infested by the same pest species together.

In Shambat area U. hystricellus was only recorded on eggplant (Solanum melongena L.) and a wild host “Gubbein” (Solanum dubium Fresen.), while a third wild host “Gubbein El Bagr” (Solanum incanum L.) was recorded only from the Northern State. The first two hosts were already reported by Drake and Ruhoff (1965), Schmutterer (1969), and Salih (1991), but the latter host was a new record. However, there were some other hosts reported for U. hystricellus in Sudan, including potato, Solanum tuberosum L. (Schmutterer, 1969), Datura stramonium L. and Datura innoxia Mill. (Salih, 1991), but these hosts were found free of any lace bug species or signs of damage as a result of the seasonal surveys carried out during the present research work. Moreover, the results obtained contradict what has been stated by Pollard (1955) and Rasool et al. (1986) who showed Abutilon spp. as hosts of U. hystricellus. According to these results it can be declared that this pest does not infest

c Abutilon spp. which were found entirely attacked by the other lace bug species, Urentius euonymus. This was insured by the differences detected in the morphological characters (Figs. 1-11), duration of immature stages (Tables 17 and 18), sizes and colours, between the two species on their different host plants. Moreover, adults of lace bugs collected from Cajanus cajan and Abutilon sp. were died within three to five days when confined to eggplant seedlings in the laboratory. As with regard to colours, sizes and some morphological characters of adults and last instar nymphs of U. hystricellus, the results were nearly similar to what has been reported by some workers in Sudan (Schmutterer, 1969; Guddoura, 1977, and Salih, 1991). On the other side, the results may partially come in consistency with the findings of Singh and Mann (1986) in India, who reported that Datura stramonium L., as well as many other tested plants, are not suitable hosts for U. hystricellus, because females did not oviposit on these plants even though survived for one to six days when confined to them.

Urentius euonymus, on the other hand, was detected to inflict serious damage on five host plants including pigeon pea (Cajanus cajan (L.) Huth.), “Hambouk” (Abutilon spp.), “Um shidaida” (Sida alba L.), “Taroob” (Chrozophora plicata (Vahl.) A. Juss. ex Spreng) and “Adana” (Rhynchosia memnonia (Del.) DC.). The first three hosts were already reported by several authors (Drake and Ruhoff, 1965; Schmutterer, 1969, and Baloch et al., 1977 and 1978), while the last two were new records. One of these new hosts, “Adana” (R. memnonia), belongs to the same family, Fabaceae, of Cajanus cajan, the major cultivated host plant of U. euonymus, but the second new host, “Taroob” (C. plicata), added Euphorbiaceae as a third new family among host range of the pest. Although, all the lace bugs encountered on the above mentioned five host

d plants were declared as U. euonymus due to similarities in some general morphological characters between them, but existence of different races among these insects could not be excluded, a case which might have been developed through progressive adaptability of each insect to its intimate host plant over a very long time. This could be true for an insect like U. euonymus infesting various host plants among different families, a habit which was not generally experienced in lace bugs. According to the literature these pests were mainly restricting their feedings either on a single host or on closely related host plants (Dake and Ruhoff, 1965). The other lace bug species detected on more than one host during this study were U. hystricellus and G. scrophicus, each had its all host plants restricted to only one family (Solanaceae for the former species and Compositae for the latter one). Whatsoever, the detection of some lace bug species (e.g. U. hystricellus, U. euonymus, G. scrophicus and “Guddiem” lace bug) in other parts of the country may indicate their wide distribution and importance in agricultural ecosystems in Sudan.

As seen from the results, lace bugs are generally sluggish insects. This is especially true for the nymphal stages, if not so for the adults. For general viewers, this habit seems to be a disadvantage, but this is not the fact at least in the case of the lace bugs. In spite of their quiescent habit, high populations of most lace bug species were counted throughout the developmental stages of their host plants. Less movement actually makes an organism unnoticeable by its natural enemies. In the same context, Edmunds (1975) stated that “to remain undetected a cryptic must not move”. In addition, the results explained so many inherent morphological and behavioural characteristics of lace bugs acquired from their parents, which make them inaccessible to their natural enemies. The imbedded eggs of all species, spines and hairs those mimicking host

e plants (e.g. nymphs of Thaumamannia sp.; Fig. 16), lacy wings of most species, cryptic colours (e.g. “Rehan” lace bug and nymphs of “Guddeim” lace bug), cryptic movements (e.g. adults of Galeatus scrophicus and “Guddiem” lace bug) and gregarious habit of different species, were all constitute source of camouflage and concealment in these lace bugs to escape their enemies. However, the presence of glandular spines in some species and the phenomena of camouflage in lace bugs in general were discussed by Drake and Ruhoff (1965). It is also noteworthy to add here an statement by Edmunds (1975), which says “a group of animals in an area is less likely to be encountered by a predator than are the same number of animals dispersed widely over the same area”.

The results of studying seasonalities of U. hystricellus have shown continuous activity and breeding of this pest during all times of the year. The detection of the immature stages during all seasons suggests the absence of any resting stage of the pest in this country. This agreed with Salih (1991) who mentioned that, no diapausing stage of the pest was found in Sudan. There were two periods during the year where the population of U. hystricellus showed its highest increase (Table 3). The first period occurred during the end of the winter season (February – April), while the second peak of population increase was found in the period following the rainy season (September – October). The same population trend recorded on eggplant also occurred on the wild host Solanum dubium. During autumn, the populations were relatively lower compared with the other seasons. The rainy season seems to favour the population build up of the pest, but direct rainfall was noticed to exert a negative effect on eggplant lace bugs. Heavy showers on the leaves plus upward splashing of muddy or sandy rain water from the ground were found to kill large numbers of the bug and, hence, low counts were

f depicted during such period. Thereafter, quick resurgence of the pest occurs when rains ceased. No similar research on this bug has been attempted in Sudan, but the few available data showed nearly similar results, especially with regard to the winter season, indicating January – February as the best time of population build up (Pollard, 1955, and Schmutterer, 1969). In Thailand, Tigvattn (1990) reported the highest infestation and most crop losses to occurr in a relatively long period extending mainly from March to June. On the other hand, the negative effect of the rainfall on populations of other insect pests was reported by some scientists (e.g. Hanna, 1950, and El Khidir, 1960).

“Adasi” lace bug, Urentius euonymus, was studied for the first time in this research in Sudan. This species is closely related to the former one, Urentius hystricellus, and showed more or less similar population trends with two peaks, one extending over a long period during late winter and summer time (January – July), and the second peak during the period following the rainy season (September – October). It is obvious that, the population of the two Urentius spp. were higher in the year 2001, than in the years 2000 and 2002. This condition could be attributed to the highest rainfall preceded during the autumn season of the year 2001, compared with the other two years (Fig. 23).

The population counts of Galeatus scrophicus was found to be higher during winter, as compared with the autumn season. The sunflower variety HSHA9 was more susceptible to attack and sustained relatively higher population of insects than the variety HYSUN33. Fortunately, the latter variety is the most important one grown commercially in Sudan. Since sunflower was introduced in the rotation of irrigated schemes (e.g. Gezira scheme) during the last years to be grown as a winter crop, the variety HYSUN33 seems to be suitable when the problem of lace bugs is

g considered. However, among other pests of sunflower, an outbreak of the flower beetle, Pachnoda interrupta OL. (Coleoptera: Cetoniidae) was observed during the autumn season (September – October), 2003, causing 100% damage of sunflower seeds on the two varieties grown. The occurrence of this pest was observed during the past years to inflict damage on different vegetables (e.g okra), some weeds (Abutilon spp.) and fruit trees in Shambat area.

The distribution of lace bugs on their host plants was found to be different according to the species of the pest. The populations of Urentius spp. were generally recorded on the lower surfaces of the leaves, while those of sunflower lace bug were mainly found on the upper surfaces. For both pests the lower leaves generally sustain the highest population in each host plant. This factor, where the pest species is found, is important when chemical control is applied, so that spraying will be directed towards the target pest. In the context of control measures, alternative host plants should be considered, since six host species other than sunflower were found highly infested by G. scrophicus, and a number of hosts were recorded for Urentius spp. in the field. The current research study on sunflower lace bug was the first one to be conducted in Sudan. Because the seasonality of the pest was studied only in two seasons, more research is needed to cover this aspect. However, the results obtained partially contradict the findings reported abroad as with respect to seasonality and distribution of the pest within the host plant. In India an outbreak of the pest was reported to occurr on sunflower during May – September (Rao and Thirumalachar, 1977), and the insects were found to prefer the lower part of the plant and the lower surface of the leaf as recorded in Iraq by Al Mallah (1999). The difference in results could be

h due to variation in host plants characters and other environmental conditions between those countries and Sudan.

Among the newly encountered species the “Rehan”, “Sidir”, “Guddiem” and “Andrab” lace bugs were detected later in the year 2002. Therefore, preliminary assessments of their population levels were performed during the last year of the present investigation (November – October, 2002/2003). These species were considered as major pests exerting severe damage on their host plants especially during winter months (November – April; Table 16). Badly damaged trees of “Sidir” (Ziziphus spina-christi) and “Guddeim” (Grewia tenax), were observed defoliated at the end of the winter season, as a result of high infestation by the lace bugs. The importance of these pest species also came from the fact that they damage an important group of our indigenous natural vegetation. For instance, “Rehan” (Ocimum basilicum) is one of the familiar ornamental plants, and its oil is of great potential in industry used for many purposes in cosmetics, liqueurs, medicines and perfumes. “Rehan” materials also proved effective as bactericides and fungicides, as well as, repellent for some insects (Dube et al. 1989; Sinha and Gulati, 1990, and Anon., 2001). On the other hand, the fruits of “Sidir” (Ziziphus sp.) and “Guddeim” (G. tenax) trees are very nutricous and preferable and became one of the flourishing marketable commodities in all parts of the country. Flowers of these trees, especially of “Sidir” were considered preferable by the honey bees and important in conservation of the agro- ecosystems (Satti, 2001, and Abdel Wahab, 2003).

As it appeared from the results, damage of the lace bugs was unevenly distributed in the field. On most weeds and field crops it was observed that some plants were highly infested showing signs of severe damage, while others in vicinity were entirely free of infestation. Such

i cases were also observed on trees like “Sidir” (Ziziphus sp.) and “Guddeim” (G. tenax) during the period of high infestation (winter season) by these lace bugs. Similarly, some trees of each species in the area were found fostering high populations of pest, while others were completely free. Furthermore, the distribution of lace bugs within each host plant was also observed restricted randomly to certain leaves. Such conditions could be attributed to the behavioural habits of the lace bugs. These insects used to live in a gregarious way, probably through specific pheromonal communication. Therefore, when they invade one host, and due to their sluggishness, they stay crawling in limited area feed and breed together without any tendency to expand their distribution to other hosts. In these limited areas the offsprings produced displayed the real damage of the lace bugs. Accordingly, symptoms of feedings were noticed firstly in certain places on leaves (e.g. basal damage vs. marginal leaf damage in Urentius spp. and G. scrophicus, respectively), then certain leaves and certain plants in a random uneven distribution.

The results of studying the duration of the pre-imaginal stages of some lace bugs have clearly insured the effects of climatic conditions, especially temperatures on the development and hence population abundance of these pests. The pre-oviposition, incubation and nymphal periods of all studied insects were longer during winter season, compared with the autumn season. Hence, more population of lace bugs appeared during autumn time (Table 3). However, similarly improved temperature at the end of the winter time showed a positive effect on the population build up (Table 3). Temperature is therefore a critical factor as indicated by Singh and Mann (1986) when studying seasonality of U. hystricellus in India. No biological or other similar studies on lace bugs were conducted in the Sudan, except for Urentius hystricellus. However, the

j current findings concerning duration of the immature stages showed nearly similar duration of the total nymphal stages (winter result; Table 17), as compared with that reported by Salih (1991). The period from egg laying to emergence of adult (12 days) during autumn season (calculated from Table 17) was found similar to what has been shown by Pollard (1955) and Schmutterer (1969).

As shown in the results the encountered predatory groups of the lace bugs included mainly members of the chrysopids and spiders and to less extent some coccinellid species. All the detected species were known as generalized predators feeding on various arthropods on different host plants. However, most of these predators were already reported from different field and vegetable crops at Shambat area (Bashir, 1968; Satti et al., 1998, and Kuol, 2003). Also, the preying of such predators on lace bugs was reported by several scientists world wide (Shetlar, 1991; El Amin, 1998; Kyhl and Hahn, 1999; Anon., 2002, and Gouveia and Ohlendorf, 2002).

Although some coccinellids were detected preying on lace bugs in the field, this group was categorized in this study as inefficient predators of lace bugs, when compared with chrysopids and spiders due to several reasons. Firstly, the coccinellids were found to prefer aphids more than any other arthropods. The results of continuous surveys in the field have revealed that coccinellids were more abundant on plants infested with aphids (e.g. alfalfa, forage sorghum and maize) than on those plants harbouring lace bugs. Even, their presence and build up on lace bug infested plants were found to be more synchronized with aphids. For instance the infestation of eggplant with Aphis gossypii during winter season was found to attract numerous coccinellid species like Hippodamia, Cydonia and Scymnus, more than they were, when these

k plants were free of aphids. Actually, the dense plant canopy in alfalfa, and the whorled leaves in sorghum and maize crops seem to provide suitable micro-climate for some species of aphids and other soft bodied insects to live, especially during hot months. These habitats were then targeted by some coccinellids during scarcity of aphids in other fields. Moreover, besides aphids and other insects, these crops also contain pollen grains which provide an additional source of feedings for the coccinellids. A similar observation was reported by Satti et al. (1998) showing congregation of some coccinellids associated with colonies of aphids inside leaf whorls of maize plants especially during autumn and summer seasons. Furthermore, the results from one view agreed with Kuol (2003) who reported that different coccinellid species, particularly Hippodamia were more prevalent on plants harbouring different species of aphids. The same author (2003) even found that Hippodamia variegata relatively preferred feeding on certain aphid species like Melanaphis sp., than on the others. Secondly, the result of feeding test conducted in the laboratory (Table 20) has shown the least feeding ability by coccinellids (25.33 +7.31 – 51.67 + 2.14 lace bug nymphs/day) compared with chrysopids (196.33 + 17.64 nymphs/day) and spiders (101.00 + 5.03 – 180.67 + 14.53 nymphs/day). Lastly, it was observed that when adults of Hippodamia and Cydonia were enclosed in petri dishes together with the nymphs of U. hystricellus during the feeding test, these beetles avoided being in contact with those nymphs for a long time, though they seemed very hungry. This might suggest the presence of repellent secretion produced by such nymphs. According to the literature, bad scented chemical secretions were generally experienced by various hemipteran bugs. It was stated that some hemipteran insects secrete a defensive fluid from their dorsal abdominal glands which repelled certain predatory

l arthropods (Edmunds, 1975). Moreover, it was reported earlier by Drake and Ruhoff (1965) that some lace bug species possess glandular spines.

On the other hand, chrysopids and spiders can be considered as the two major groups of predators of lace bugs. They were more prevalent and found associated with lace bugs on their different host plants than the other predators. The observed voracious feedings of chrysopid larvae on the nymphs of lace bugs in the field, and the huge colonies of different lace bug species entangled and preyed upon by spiders (Pl. 15 a-c) together with the higher feeding capacities of both groups of predators (compared with coccinellids; Table 20), put them among the main suppressive biotic factors of lace bugs. Although, the spiders consumed relatively lower numbers of lace bugs than the chrysopids, during the feeding test, but the population numbers of the first group, encountered with lace bugs in the field, were found to be higher than those of the chrysopids and other predators. Moreover, spiders were usually dominant during all seasons on almost all investigated host plants of the lace bugs. Therefore, the ranking of the recorded predators according to their importance as biocontrol agents for the lace bugs could place the spiders on the top, followed by the Chrysoperla pudica and lastly the coccinellid species. But, due to their various species from one host plant to another, these spiders need to be identified and evaluated. For instance, the species of spider prevalent on eggplant (Pl. 14a) associated with lace bugs, was found to be different from that dominant on cereal crops (Pl. 14b).

However, the results of seasonality studies have shown that numbers of total predators were generally higher during winter compared with the other seasons. The populations trends of predators encountered on Urentius hosts (Table 22 and Figs. 27, 28 and 29) were found to be more synchronized with the populations of their preys (i.e. U. hystricellus

m on eggplant [Table 2] and “Gubbein” [Fig. 24], and U. euonymus on pigeon pea [Fig. 25] and “Hambouk” [Fig. 26]). Among the few available literature on natural enemies in Sudan, some workers emphasized the importance of spiders and chrysopids in various agricultural fields, and showed that they were more abundant during winter season (Bashir, 1968; Herrera, 1986a; Abdalla and Beije, 1997; Beije and Ahmed, 1997; Dabrowski et al., 1997, and Satti et al., 1998).

The data on the different predators surveyed during the current study were collected under normal farming practices in fields of Shambat area. In fact, no body among the farmers met was found aware about the natural enemies in his field. Cultural practices used were not based on scientific findings, chemical insecticides were used frequently and no body knows what chemicals he use and what hazards they could do. Therefore, most of the practices used were found really destructive to the natural enemies. For instance during cuttings of alfalfa (Medicago sativa), it was observed that a bulk of immature stages (larvae + pupae) of Hippodamia variegata were destroyed or fed to animals with forage. Sometimes the same thing occurred when cutting forage sorghum, maize and other leguminous crops. However, if such practices like strip cuttings in alfalfa was adopted, and other crops harvested when they sustain the least numbers of natural enemies, and the rest of field practices were based on knowledge, the populations of the detected predators would have taken other trends.

As reported in the literature, Khartoum State is rich in its flora and natural fauna (Abdalla, 1968; Bashir, 1968; Schmutterer, 1969;

Guddoura, 1977; Guddoura et al., 1984; Bebawi and Neugebohrn, 1991, and Satti et al., 1998), but such biological diversity needs to be protected

n and well managed (pests and enemies) through sound technical packages based on scientific research.

o REFERENCES

Abd alla, A.M. (1968). Studies on the ecology of the vegetation of the Khartoum district. M. Sc. Thesis, Faculty of Agriculture – University of Khartoum, Sudan. 264 pp. Abd alla, I. B., and Beije, C.M. (1997). The impact of major predators on the wheat aphid in Gezira. In: Dabrowski, Z.T. (ed.), Integrated Pest Management in Vegetables, Wheat and Cotton in the Sudan. Aparticipatory Approach. pp. 165 – 167. ICIPE Science Press, Nairobi, Kenya. 245 pp. Abdel Wahab, S.M. (2003). Flowering time of the plants of Khartoum State with reference to their importance for honey bees. M.Sc. Thesis, Faculty of Agriculture, University of Khartoum, Sudan. 57 pp. Abud Antun, A.J. (1991). Presence of the avocado lace bug, Pseudacysta perseae (Heidmann) (Hemiptera: Tingidae) in Dominican Republic. Primera Jornado de Proteccion Vegetal, University of Santo Domingo, Santo Domingo, Dominican Republic, (Abstract p.4). Al Mallah*, N.M. (1999). First record and biological study of Galeatus scrophicus Saund. and Galeatus helianthi O. and L. attacking sunflower crop in Iraq. Arab University Journal of Agricultural Sciences, 7 (2). pp. 673 – 688. Anonymous (2001). Treating livestock with medicinal plants: Beneficial or toxic. Ocimum basilicum, O, americanum and O. micranthum. Animal Science Webmaster, University of Cornell. Anonymous (2002). Lace bugs. http://edis.ifas.ufl.edu/MENU IG. University of Florida. Balraj*, S.; Battu, G.S., and Atwal, A.S. (1975). Studies on the spider predators of the maize borer, Chilo partellus (Swinhoe) in the Punjab. Indian Journal of Entomology, 37 (1). pp. 72 – 76. Baloch*, G.M.; Khan, A.G., and Zafar, T. (1977). Investigations on the insect enemies of Abutilon, Amaranthus, Rumex and Sorghum in Pakistan. Report of Commonwealth Institute of Biological Control, Pakistan Station, 1975 – 1976. 44 pp. Baloch*, G.M.; Khan, A. G., and Zafar, T. (1978). Natural enemies of Abutilon, Amaranthus, Rumex and Sorghum in Pakistan (for the USA). Trinidad, Commonwealth Institute of Biological Control, Report of work carried out during 1976. pp. 61 – 62.

p Bashir, M.O. (1968). Studies on the natural enemies of some major insect pests of "Berseem" in Khartoum Province. M.Sc. Thesis, Faculty of Agriculture - University of Khartoum, Sudan. 126 pp. Bebawi, F.F., and Neugebohrn, L. (1991). A review of plants of northern Sudan, with special reference to their uses. Germany Agency for Technical Cooperation (GTZ), Eschborn - Federal Republic of Germany. 294 pp. Beije, C.M., and Ahmed, M.A. (1997). Natural enemies and cotton pest control in Sudan. In: Dabrowski, Z.T. (ed.), Integrated Pest Management in Vegetables, Wheat and Cotton in the Sudan. A participatory Approach. pp. 177 – 190. ICIPE Science Press, Nairobi, Kenya. 245pp. Beije, C.M., and G. Elanbia, K. (1997). The role of natural enemies in vegetable IPM in central Gezira and Blue Nile area. In: Dabrowski, Z.T. (ed.), Integrated Pest Management in Vegetables, Wheat and Cotton in the Sudan. A participatory Approach. pp. 107 – 116. ICIPE Science Press, Nairobi, Kenya. 245pp. Borror, D.J.; Delong, D.M., and Triplehorn, C.A. (1976). An introduction to the study of insects. 4th ed., Holt, Rinehart, Winston, New York and London. Borror, D.J., and White, R.E. (1970). A field guide to the insects of America North of Mexico. Houghton Mifflin Company, Boston. Brempong - Yaboah*, C.Y., and Okoampah, N.D. (1989). Afield experiment on the effects of some insecticides on the pests of garden egg (Solanum integrifolium) at Legon. Applied Entomology and Zoology, 24 (4). pp. 343 – 348. Burgstaller, H.; Mohamed, M.B., and Hassan, M.S. (1984). A hand book of vegetable production and vegetable pests and diseases in the Sudan. Sudanese German Plant Protection Programme, Plant Protection Department, Khartoum North. 66pp. Cilliers*, C.J. (1987a). Notes on the biology of the established insect natural enemies of Lantana camara L. (Verbenaceae) and their seasonal history in South Africa. Journal of Entomological Society, South Africa, 50 (1). pp. 1 – 13. Cilliers*, C.J. (1987 b). The evaluation of three insect natural enemies for the biological control of the weed Lantana camara L. Journal of Entomological Society, South Africa, 50 (1). pp. 15 – 34. Dabrowski, Z.T.; Beije, C.M.; Bannaga, A.; El Allam, E.M., and Maragan, M.C. (1997). An improved monitoring procedure for the wheat aphid. In: Dabrowski, Z.T. (ed.), Integrated pest Management in Vegetables, Wheat and Cotton in the Sudan. A

q participatory Approach. pp. 147 – 156. ICIPE Science Press, Nairobi, Kenya. 245 pp. DE Long, D.M. (1965). Ecological aspects of North American leaf hoppers and their role in agriculture. Bulletin of the Entomological Society of America, 11 (1). pp. 9 – 26. Drake, C.J., and Ruhoff, F.A. (1965). Lace bugs of the world; a catalog (Hemiptera: Tingidae). Smithsonian Institution, Washington. 634 pp. Drees, B.M., and John, J. (1999). Field guide to Texas insects. Gulf Publishing Company, Houston, Texas (from Texas Extension Services). Dube*, S.; Upadhyay, P.D., and Tripathi, S.C. (1989). Antifungal physicochemical and insect repelling activity of the essential oil of Ocimum basilicum. Canadian Journal of Botany, 67 (7). pp. 2085 – 2087. Edmunds, M. (1975). Defence in animals. Longman Group, London. 357 pp. El Amin, E.M. (1998). Ecological studies on eggplant tingid bug. Annual Report 1997/98, Centre of Crop Protection, Agricultural Research Corporation, Wad Medani, Sudan. pp. 151 -153. (in Arabic). El Khidir, E. (1960). Morphological and biological studies on whiteflies in the Sudan. M.Sc. Thesis, Faculty of Agriculture – University of Khartoum, Sudan. 106 pp. El Magid, G.E. (1977). Ecological studies on Heliothis armigera Hub. (Lepidoptera: Noctuidae). M.Sc. Thesis, Faculty of Agriculture – University of Khartoum, Sudan. Faragalla, A.A., and Taher, M.O. (1988). The true spiders (Araneomorphae) in Western Region of Saudi Arabia. Series 3. Scientific Publication Centre of King Abdel Aziz University, Saudi Arabia. 28 pp. (in Arabic). Gouveia, P., and Ohlendorf, B. (2002). Lace bugs. Pest Management Guidelines, University of California Statewide IPM Program, USA.

Guddoura, E. (1977). Studies on the Heteroptera of the Sudan with special reference to species of agricultural importance. Ph.D. Thesis, Faculty of Agriculture – University of Khartoum, Sudan. Guddoura, E. (1997). Sustainable integrated pest management and integrated services for vegetable and fruit farmers in the Sudan In: Dabrowski, Z.T. (ed.), Integrated Pest Management in Vegetables, Wheat and Cotton in the Sudan. Aparticipatory

r Approach. pp. 206 – 210. ICIPE Science Press, Nairobi, Kenya. 245 pp. Guddoura, E.; Fadl, G.M., and Burgestaller, H. (1984). A survey of insect pests, diseases and weeds on vegetable crops in Khartoum Province. Acta-Horticulture, 143. pp. 359 – 367. Gurdip*, S.; Sandhu, G.S., and Singh, G. (1976). New records of spiders as predators of maize borer and maize jassid. Current Science, 45 (17). P. 642. Hagen, K.S. (1962). Biology and ecology of predaceous Coccinellidae. Annual Review of Entomology, Vol. 7. pp. 289 – 326. Hanna, A.D. (1950). The effect of rainfall on the cotton jassid, Empoasca lybica (de Berg.) in the Gezira Sudan. Bull. ent. Res. 41. pp. 359 – 369. Hanson, T., and Walker, B. (1999). Birch lace bug, Corythucha pallipes Parshly. The Entomology and Forest Resources Digital Inforation Work Group, The University of Georgia – USA. Herrera, J.M. (1986a). Natural enemies of cotton pests. Workshop on Integrated Pest Control for Cotton, 22 – 26 June 1986, FAO/ARC – Wad Medani / Sudan. pp. 22 – 48. Herrera, J.M. (1986b). Biotic vacuum created by the pesticides in the cotton agro-ecosystem of Sudan. I. Past and present status of predacious arthropods. Project GCP/SUD/025/NET, Development and Apptication of Integrated Pest Control in Cotton and rotational food crops. Field document No. 16. 43 pp. Herrera, J.M. (1992). Natural enemies of cotton pests. In: Munir, B.; Stam, P.A., and Abdel rahman, A. A. (eds.). Lectures on Integrated Pest Management in Sudan, Bulletin No. 4. pp. 54 – 72. Project GCP/SUD/025/NET, Agricultural Research Corporation, Sudan. Hill, D.S. (1983). Agricultural insect pests of the tropics and their control. 2nd ed. Cambridge University Press, London. Hoover, G.A. (1992). Lace bugs on deciduous woody ornamental plants. Penn State Entomology Department, USA. Ireland, A.W. (1948). The climate of the Sudan. In: Tothill, J.D. (ed.). Agriculture in the Sudan. pp. 62 – 82. Oxford University Press, London. Jamal, A.; Ahmed, A., and Adhami, N. (1979). Changes in carbohydrates, proteins and nudeic acid levels of Solanum melongena L. under pathogenic effect of the Urentius sentis D. Indian Journal of Entomology, 41 (2). pp. 185 – 87. Kuol, K.A. (2003). An ecological study of coccinellid predators associated with aphid pests on some important field and

s vegetable crops grown in Khartoum State. Ph.D. Thesis, Faculty of Agriculture – University of Khartoum, Sudan. Kyhl, J.F., and Hahn, J. (1999). Lace bugs on deciduous trees and shrubs. E 452 L, Extention Service, University of Mennesota, USA. Livingstone, D., and Yacoob, M.H.S. (1986). Natural enemies and biologies of the egg parasitoids of Tingidae in southern India. Uttar Pradesh Journal of Zoology, 6 (1). pp. 1 – 2. Mani, M.S. (1972). General Entomology. Oxford and IBH Publishing Co. Mead, F.W. (1998). Avocado lace bug, Pseudacysta perseae (Heidemann) (Insecta: Hemiptera: Tingidae). EENY – 39, University of Florida, USA. Misra*, R.M. (1985). A note on Leptobyrsa decora Drake (Hemiptera: Tingidae). A biocontrol agent of Lantana camara (Verbenaceae). Indian Forestry, 111 (8). pp. 641 – 644. Onder*, F., and Lodos, N. (1983). Preliminary list of Tingidae with notes on distribution and importance of species in Turkey. Ziraat Fakultesi Yayinlari Ege Universitesi, No. 449. 51 pp. Pollard, D.G. (1955). The insect pests of vegetables in the Sudan. Bulletin No. 16. Agricultural Publication Committee, Ministry of Agriculture. Khartoum, Sudan. 76 pp. Pollard, D.G. (1959). Feeding habits of the lace bug Urentius aegyptiacus Bergevin (Hemiptera: Tingidae). Annals of Applied Biology, 47 (4). pp. 778 – 782. Pruthi, H.S. (1925). The morphology of the male genitalia in Rhynchota. Transactions of the Royal Entomological Society of London. Parts. 1, 11. pp. 127 – 267. Rao*, K.J., and Thirumalachar, D.K. (1977). Galeatus scrophicus Saud. (Hemiptera: Tingidae), a new tingid pest of sunflower and niger in Karnataka. Current Research, 6 (7). pp. 119 – 120. Rasool*, G.; Ahmed, N., and Malik, N.A. (1986). The bringal lace bug (Urentius sentis Distant) as a pest of cotton and its chemical control. Journal of Agricultural Research. Lahore, 24 (4). pp. 321 – 323. Rath, U.C.W. (1954). The climate of the Sudan a factor in the social and economic development of the country. Proceedings of a Conference of the Philosophical Society of the Sudan on Food and Society in the Sudan, Khartoum, 1953. Mc Corquodale and Co. (Sudan), Ltd. 7 pp. Rohilla*, H.R., Singh, H.V.; Gupta, D.S.; Krishnan, S., and Singh, K. (1980). Pest complex other than diseases of sunflower, Helianthus annus, in Haryana. Indian Journal of Plant Protection, 8 (2). pp. 117 – 182.

t Sadeghi*, E., and Esmailli, M. (1992). Preying habits and hibernation site of Coccinella septempunctata L., Hippodamia (Adonia) variegata (Goeze), Psyllobora vigintiduopunctata L. in Karaj. Journal of Entomological Society of Iran, 11 (1 – 2). pp. 19 – 34. Saharaoui*, L. (1994). Survey and study of some bioecological aspects of entomophagous coccinellids (Coleoptera: Coccinellidae) in Algeria. Journal of African Zoology, 108 (6). pp. 537 – 546. Salih, T.M. (1991). Bionomic, varietal susceptibility and control of the eggplant tingid bug, Urentius hystricellus (Richter) (Hemiptera: Tingidae). M.Sc. Thesis, Faculty of Agriculture – University of Khartoum, Sudan. Satti, A.A. (2001). Sources of natural foraging for honey bees in Shambat area. Annual Scientific Report, Environment and Natural Resources Research Institute, The National Centre for Research, Sudan. pp. 111 – 115 (in Arabic). Satti, A.A.; Bashir, N.H.H.; El Khidir, E., and Nasr, O.E. (1998). Detection and seasonality monitoring of predators associated with insect pests complex of Cucumis melo L. (Muskmelon), at Shambat area. University of Khartoum Journal of Agricultural Sciences, 6 (2). pp. 49 – 60. Satti, A.A., and Nasr, O.E. (1999). Evaluation of neem (Azadirachta indica A. Juss.) seed kernels aqueous extract in controlling the main insect pests on eggplant (Solanum melongena (L.)). Annual Scientific Report, Environment and Natural Resources Research Institute, The National Centre for Research, Sudan. pp 17 – 26. Satti, A.A., and Nasr, O.E. (2000). Evaluation of neem (Azadirachta indica) seed kernels aqueous and organic extracts in controlling the main insect pests on eggplant (Solanum melongena). Annual Scientific Report, Environment and Natural Resources Research Institute, The National Centre for Research, Sudan. pp. 43 – 52. Schmutterer, H. (1969). Pests of Crops in Northeast and Central Africa. Gustav Fisher Verlag. Stuttgart. Germany. 296 pp. Scuder, G.G.E. (1959). The female genitalia of the Heteroptera: Morphology and beering on classification. Transactions of the Royal Entomological Society of London, Vol. 111. pp. 405 – 467. Shetlar, D.J. (1991). Lace bugs. HYG – 2150-91, Ohio State University Extention Fact Sheet. Singh, L., and Mann, H.S. (1986). Seasonal activity and population build- up of tingid bug, Urentius hystricellus Richter (Hemiptera:

u Tingidae) in the Punjab. Indian Journal of Ecology, 13 (2). pp. 301 – 306. Singh*, L., and Mann, H.S. (1995). Morphometric studies on tingid bug, Urentius hystricellus Richter attacking brinjal, Solanum melongena L. Journal of Insect Science, 8 (1). pp. 55 – 58. Sinha, G.K., and Gulati, B.C. (1990). Antibacterial and antifungal study of some essential oils and some of their constituents. Indian Perfumer, 34 (2). pp. 126 – 129. Tigvattn*, A.S. (1990). Studies on the bionomics and local distribution of some lace bugs in Thailand. 111. Urentius echinus Distant (Hemiptera: Tingidae). Kaen-Kaset-Khon-Kaen Agricultue Journal, 18 (5). pp 251 – 260 Vaeravel*, R., and Bhaskaran, P. (1994). Relationship between various growth stages and pest occurrence in brinjal (Solanum melongena L.). Pest Management and Economic Zoology, 2 (2). pp. 171 – 173. Venkatraman, T.V. and El-Khidir, E. (1967). Observations on crop pests in the Sudan in 1966/67. FAO Plant Protection Bulletin, 15, pp. 115-116. Verma*, N.D.; Gupta, D.S., and Sing, H.V. (1974). Biology of tingid bug Galeatus scrophicus Saund. (Hemiptera: Tingidae) on sunflower. Haryana Agricultural University Journal of Research, 4 (1). pp. 13 – 17. Weems*, H.V., and Whitcomb, W.H. (1977). The green lynx spider, Peucetia viridans (Hentz) (Araneae: Oxyopidae), Entomology Circular, Division of Plant Industry, Florida Department of Agriculture and Consumer Services, No, 181.

* Seen as abstracts only.

v Table (14). Comparisons of the mean counts of different stages of Galeatus scrophicus, between the two sides of 50 plant leaves, in two varieties of sunflower, during December – January (2001/2002), at Shambat

Variety and Counts HYSUN 33 HSHA 9 (Adults + (Adults) (Nymphs) (Adults + Side of (Adults) (Nymphs) Nymphs) Nymphs) leaves X ± S.E X ± S.E. X ± S.E X ± S.E X ± S.E X ± S.E

Upper 3.53 ± 1.54 ns 16.13 ± 4.27 ns 19.67 ± 4.41 ns 4.93 ± 3.01** 22.33 ± 6.39* 27.27 ± 8.25* Lower 1.27 ± 0.18 9.40 ± 3.49 10.67 ± 3.32 0.47 ± 0.27 8.73 ± 4.40 9.20 ± 4.82

** = Highly significant difference (at P= 0.01) * = Significant difference (at P≥ 0.05) ns = Non significant difference Table 30. The weekly population means (per 1m2/plot) of coccinellid predators encountered on Medicago sativa, during two consecutive years (2001 – 2002) of surveys in Shambat area. Predators 2001 2002 Hip. Cyd. C.U. Scy. Total Hip. Cyd. C.U. Scy. Total Date A. N. A. N. 2/Jan. 1.33 2.00 0.00 0.00 0.33 3.66 1.00 1.33 0.00 0.33 1.67 4.00 9.1. 3.00 1.67 0.00 0.00 1.00 5.67 5.33 2.00 0.33 0.00 0.00 7.66 16.1 3.00 2.00 0.00 0.00 0.67 5.67 0.33 0.67 0.00 0.00 0.67 1.67 23.1 2.33 2.33 0.00 0.00 0.00 4.66 2.33 0.00 0.00 0.00 0.00 2.33 30.1 2.00 1.33 0.33 0.00 0.33 3.99 3.00 2.00 0.33 0.00 0.67 6.00 6.2 3.00 2.00 0.00 0.00 0.33 5.33 2.67 0.00 0.00 0.00 0.00 2.67 13.2 2.67 3.00 0.00 0.00 0.67 6.34 3.67 7.33 0.00 0.00 0.00 11.00 20.2 4.00 3.33 0.00 0.00 0.00 7.33 5.67 1.67 0.33 0.00 0.67 8.34 27.2 5.00 2.33 0.00 0.00 0.33 7.66 4.67 3.00 0.00 0.00 0.33 8.00 6.3 1.00 0.33 0.00 0.00 0.00 1.33 6.67 3.67 0.00 0.00 3.67 14.01 13.3 12.67 6.00 0.00 0.00 0.00 18.67 1.00 0.00 0.00 0.00 0.00 1.00 20.3 6.00 0.00 0.00 0.00 0.00 6.00 4.00 2.00 0.00 0.00 0.67 6.67 27.3 6.00 0.33 0.00 0.00 0.00 6.33 5.00 2.00 0.00 0.00 0.33 7.33 3.4 5.33 2.00 0.00 0.00 0.00 7.33 4.67 0.00 0.00 0.00 0.00 4.67 10.4 5.67 1.67 0.00 0.00 0.33 7.67 2.00 0.00 0.00 0.00 0.00 2.00 17.4 5.33 9.33 0.00 0.00 0.00 14.66 3.33 0.00 0.00 0.00 0.00 3.33 24.4 5.33 2.33 0.00 0.00 0.33 7.99 4.00 3.33 0.00 0.00 0.00 7.33 1.5 6.33 0.67 0.00 0.00 0.00 7.00 4.33 3.33 0.00 0.00 0.00 7.66 8.5 4.67 13.00 0.00 0.00 0.00 17.67 4.33 2.00 0.00 0.00 0.33 6.66 15.5 5.00 5.67 0.00 0.00 0.00 10.67 4.67 0.67 0.00 0.00 0.00 5.34 22.5 4.33 3.33 0.00 0.00 0.00 7.66 2.00 0.33 0.00 0.00 0.00 2.33 29.5 6.00 4.00 0.00 0.00 0.67 10.67 4.67 2.00 0.00 0.00 0.33 7.00 5.6 6.33 21.67 0.00 0.00 0.00 28.00 7.67 0.00 0.00 0.00 0.33 8.00 12.6 5.00 3.67 0.00 0.00 0.33 9.00 7.00 3.00 0.00 0.00 0.00 10.00 19.6 6.00 3.00 0.00 0.00 0.00 9.00 12.33 2.00 0.00 0.00 0.00 14.33 26.6 8.33 0.00 0.00 0.00 0.00 8.33 5.67 1.00 0.00 0.00 0.00 6.67

b 2001 2002 Hip. Hip. 3.7 3.00 0.00 0.00 0.00 0.00 3.00 4.67 1.33 0.00 0.00 0.00 6.00 10.7 2.67 0.00 0.00 0.00 0.33 3.00 0.67 0.67 0.00 0.33 0.00 1.67 17.7 2.33 0.00 0.00 0.00 0.00 2.33 4.33 0.00 0.00 0.00 0.00 4.33 24.7 4.67 0.00 0.00 0.00 0.00 4.67 3.67 0.00 0.67 0.00 0.00 4.34 31.7 2.00 0.00 0.00 0.00 0.00 2.00 0.00 0.00 0.33 0.00 0.00 0.33 7.8 1.00 0.00 0.33 0.00 0.00 1.33 0.00 0.00 0.00 0.00 0.00 0.00 14.8 2.00 0.00 0.00 0.00 0.00 2.00 1.00 0.00 0.00 0.00 0.00 1.00 21.8 1.33 0.00 0.33 0.00 0.00 1.66 2.00 0.33 1.00 0.00 0.00 3.33 28.8 2.00 2.00 0.33 0.00 0.33 4.66 1.67 0.00 0.00 0.00 0.00 1.67 4.9 2.00 3.00 0.00 0.00 0.00 5.00 3.00 2.00 0.00 0.00 0.33 5.33 11.9 5.33 19.33 0.67 0.00 1.33 26.66 2.67 2.33 0.33 0.00 0.33 5.66 18.9 7.00 40.33 0.00 0.00 0.00 47.33 1.00 0.00 0.00 0.00 0.00 1.00 25.9 2.00 3.67 1.67 0.00 1.00 8.34 2.00 0.67 0.67 0.00 0.33 3.67 2.10 2.00 3.00 0.33 0.00 0.33 5.66 0.00 1.00 0.00 0.00 1.33 2.33 9.10 2.00 1.67 0.00 0.00 0.33 4.00 5.33 7.00 0.33 0.00 0.00 12.66 16.10 0.00 0.00 0.00 0.00 0.00 0.00 3.67 1.00 0.00 0.00 0.33 5.00 23.10 8.00 2.33 0.33 0.00 0.00 10.66 1.00 0.00 0.00 0.00 0.00 1.00 30.10 3.00 9.00 0.00 0.00 1.00 13.00 0.00 0.00 0.00 0.00 0.00 0.00 6.11 1.67 1.33 0.00 0.00 0.67 3.67 2.00 1.33 0.00 0.00 0.33 3.66 13.11 11.00 3.33 0.00 0.00 0.00 14.33 1.33 0.33 0.00 0.00 1.00 2.66 20.11 1.00 0.00 0.00 0.00 0.33 1.33 0.00 0.00 0.00 0.00 0.00 0.00 27.11 2.00 1.00 0.00 0.00 0.33 3.33 1.00 0.33 0.00 0.00 0.33 1.66 4.12 0.33 1.67 0.00 0.00 0.00 2.00 0.33 0.67 0.00 0.00 0.67 1.67 11.12 2.33 0.67 0.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.00 0.00 18.12 1.67 0.33 0.00 0.00 1.00 3.00 1.00 0.33 0.00 0.00 0.33 1.66 25.12 1.00 5.33 0.00 0.00 033 6.66 0.00 0.00 0.00 0.00 0.00 0.00

* Hip. = Hippodamia sp.; Cyd. = Cydonia sp.; C.U. = Coccinella undecimpunctata; Scy. = Scymnus spp.; A. = adults, and N. = Nymphs.

c Table 33. The weekly population means (per 25 plants) of coccinellid predators encountered on "Abu 70" (Sorghum bicolor), during three consecutive years (2000 – 2002) of surveys in Shambat area. Predators 2000 2001 2002

Hip. Hip. Hip. Date Cyd. C.U. Scy. Total Cyd. C.U. Scy. Total Cyd. C.U. Scy. Total A. N. A. N. A. N. 2/Jan. 4.00 0.00 4.67 0.00 0.00 8.67 3.00 0.33 3.00 0.00 0.67 7.00 9.1. 2.00 2.00 8.00 0.00 6.00 18.00 0.67 0.00 0.00 0.00 0.00 0.67

16.1 5.00 4.00 10.00 0.00 1.00 20.00 0.00 0.00 3.67 0.00 0.00 3.67 23.1 6.00 6.00 11.00 0.00 2.00 25.00 2.00 6.00 0.00 0.00 0.00 8.00 30.1 32.00 42.00 5.00 0.00 0.00 79.00 4.00 2.00 2.00 0.33 0.67 9.00

6.2 4.00 16.00 0.00 0.00 0.00 20.00 1.67 1.67 0.00 1.00 0.00 4.34 13.2 7.00 20.00 3.00 1.00 0.33 31.33 5.00 4.00 2.00 0.33 0.33 11.66 20.2 8.00 10.00 4.00 0.00 0.00 22.00 14.67 0.00 0.67 0.33 0.00 15.67

27.2 12.00 13.00 3.33 1.00 1.00 30.33 9.00 6.00 2.00 1.00 0.00 18.00 6.3 10.00 2.00 0.67 0.00 0.00 12.67 8.67 10.00 1.33 0.67 0.33 21.00 13.3 21.00 0.00 0.00 0.00 0.00 21.00 11.33 0.00 0.00 0.33 0.00 11.66

20.3 9.00 0.00 2.00 3.00 3.00 17.00 3.00 0.00 0.33 0.67 0.33 4.33 27.3 4.00 0.33 1.00 0.67 0.00 6.00 7.00 3.00 1.00 1.00 1.00 13.00 3.4 7.00 0.33 2.00 0.33 1.00 10.66 10.33 0.00 0.00 0.67 0.33 11.00

10.4 5.00 0.00 1.00 1.00 0.33 7.33 8.00 0.00 0.00 0.33 1.00 9.33 17.4 1.00 0.00 0.00 0.33 0.00 1.33 7.00 0.00 0.00 0.33 1.33 8.66 24.4 1.00 0.00 0.00 0.00 0.33 1.33 5.00 0.00 0.00 0.33 0.00 5.33

1.5 0.67 0.00 0.00 0.00 0.00 0.67 3.00 0.33 0.00 0.33 0.33 3.99 8.5 1.00 0.00 0.00 0.00 0.00 1.00 1.67 0.33 0.00 0.00 0.00 2.00 15.5 0.00 0.00 1.00 1.33 0.00 2.33 0.67 0.00 0.00 0.00 1.00 1.67

22.5 1.00 0.00 0.33 0.33 0.33 1.99 3.33 0.00 0.00 0.00 0.00 3.33 29.5 0.67 0.00 0.00 0.00 0.00 0.67 2.00 0.00 0.00 0.00 0.00 2.00 5.6 2.00 0.00 0.00 0.00 0.00 2.00 1.33 0.00 0.00 0.00 0.00 1.33

12.6 0.33 0.00 0.00 0.00 0.33 0.66 1.33 0.00 0.00 0.00 0.00 1.33 19.6 2.00 0.00 0.00 0.33 0.00 2.33 0.33 0.00 0.00 0.00 0.00 0.33 26.6 5.00 0.00 0.33 0.33 0.00 5.66 1.00 0.00 0.00 0.00 0.00 1.00

3.7 2.00 0.00 0.00 0.67 0.00 2.67 1.67 0.00 0.00 0.33 0.33 2.33 10.7 0.67 0.00 0.67 0.00 0.67 2.01 0.33 0.00 0.00 0.00 0.00 0.33

d Predators 2000 2001 2002

Hip. Hip. Hip. Date Cyd. C.U. Scy. Total Cyd. C.U. Scy. Total Cyd. C.U. Scy. Total A. N. A. N. A. N. 17.7 0.67 0.00 0.67 0.00 0.00 1.34 0.00 0.00 0.33 0.00 0.00 0.33 24.7 0.33 0.00 2.00 0.00 0.00 2.33 0.00 0.00 0.33 0.00 0.00 0.33

31.7 0.00 0.00 3.33 0.00 0.00 3.33 0.00 0.00 0.00 0.00 0.00 0.00 7.8 0.33 0.00 4.33 0.00 0.00 4.66 0.00 0.00 0.33 0.00 0.00 0.33 14.8 0.33 0.00 3.00 0.00 0.33 3.66 0.00 0.00 0.67 0.00 0.00 0.67 21.8 0.00 0.00 6.00 0.00 3.67 9.67 0.33 0.00 3.00 0.00 2.00 5.33 28.8 0.33 0.00 5.00 0.00 2.00 7.33 0.00 0.00 2.00 0.00 3.00 5.00 4.9 0.00 0.00 3.00 0.00 2.00 5.00 0.00 0.00 3.33 0.33 4.00 7.66 11.9 1.00 0.00 13.00 0.33 7.00 21.33 0.33 0.00 4.00 0.67 3.00 8.00 18.9 0.00 0.00 14.00 0.00 2.00 16.00 0.33 0.00 2.67 0.33 2.33 5.66 25.9 0.00 0.00 6.00 0.00 0.33 6.33 0.00 0.00 4.67 0.00 0.00 4.67 2.10 0.00 0.00 8.00 0.33 1.00 9.33 0.67 1.33 3.67 0.00 0.33 6.00 9.10 0.00 0.00 1.00 0.00 0.00 1.00 0.33 0.00 1.67 0.00 0.00 2.00 16.10 0.00 0.00 4.00 0.00 0.00 4.00 0.33 0.00 2.00 0.00 0.33 2.66 23.10 0.00 0.00 3.67 0.00 1.00 4.67 0.00 0.00 0.00 0.00 0.33 0.33 30.10 0.00 0.00 0.67 0.00 4.67 5.34 0.00 0.00 2.67 0.00 2.00 4.67 6.11 0.00 0.00 2.67 0.00 1.33 4.00 0.00 0.00 0.33 0.00 2.00 2.33 0.00 0.00 3.00 0.00 1.00 4.00 13.11 0.00 0.00 1.00 0.00 0.67 1.67 0.00 0.00 0.00 0.00 1.00 1.00 0.00 0.00 1.67 0.00 1.33 3.00 20.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.33 0.00 0.00 0.33 0.00 0.00 1.00 0.00 0.67 1.67 27.11 0.00 0.00 0.33 0.00 0.33 0.66 0.00 0.00 0.00 0.00 1.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 4.12 0.00 0.00 0.67 0.00 0.33 1.00 0.00 0.00 0.00 0.00 0.33 0.33 0.00 0.00 0.33 0.00 0.00 0.33 11.12 0.00 0.00 1.00 0.00 0.00 1.00 0.00 0.00 0.00 0.00 0.33 0.33 0.00 0.00 1.00 0.00 0.67 1.67 18.12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.67 0.33 0.33 1.33 25.12 0.33 0.00 1.00 0.00 0.33 1.66 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 1.00

* Hip. = Hippodamia sp.; Cyd. = Cydonia sp.; C.U. = Coccinella undecimpunctata; Scy. = Scymnus spp.; A. = adults, and N. = Nymphs.

e Table 34. The weekly population means (per 25 plants) of some predators encountered on "Abu 70" (Sorghum bicolor), during three consecutive years (2000 – 2002) of surveys in Shambat area.

Predators* 2000 2001 2002 Chry. Spid. Others Chry. Spid. Others Chry. Spid. Others Date 2/Jan. 5.00 3.00 5.00 3.00 1.67 3.00 9.1. 0.00 0.00 9.00 5.00 0.00 7.00 16.1 2.00 0.00 7.00 0.00 0.00 0.00 23.1 2.00 0.00 8.00 2.00 1.00 0.00 30.1 0.00 1.00 0.00 3.00 1.33 3.00 6.2 0.00 0.00 0.00 0.00 0.67 0.00 13.2 0.33 2.00 0.33 4.00 2.00 1.33 20.2 2.00 1.67 0.67 7.67 1.00 0.33 27.2 1.33 1.67 1.00 3.00 1.33 1.00 6.3 1.00 1.00 0.00 3.33 2.00 1.33 13.3 0.00 2.00 0.00 0.00 0.67 0.33 20.3 22.00 0.67 0.00 0.00 0.00 0.67 27.3 1.00 0.33 0.00 2.33 2.00 1.00 3.4 2.00 1.00 0.00 2.00 1.67 0.00 10.4 1.67 0.67 0.00 1.33 1.33 0.00 17.4 0.00 1.00 0.00 1.00 1.00 0.00 24.4 0.00 0.33 0.00 3.67 1.00 0.67 1.5 0.00 1.00 0.00 4.33 2.00 1.00 8.5 0.33 2.33 0.00 6.00 0.33 0.00 15.5 0.00 2.00 0.00 0.33 2.33 0.00 22.5 0.33 3.00 0.00 1.00 0.67 0.00 29.5 0.67 2.00 0.00 2.00 2.00 0.00 5.6 0.33 2.67 0.00 0.00 0.67 0.00 12.6 1.00 3.00 0.00 0.67 1.67 0.00 19.6 1.33 1.67 0.00 1.00 2.00 0.00 26.6 0.00 2.00 0.33 0.00 2.00 0.00 3.7 0.00 1.67 0.00 1.00 2.33 0.00 10.7 0.00 2.33 0.00 0.00 1.00 0.00

f Predators* 2000 2001 2002 Chry. Spid. Others Chry. Spid. Others Chry. Spid. Others Date 17.7 0.00 1.67 0.00 0.00 0.00 0.00 24.7 0.00 1.67 0.00 0.00 0.00 0.00 31.7 0.00 0.00 0.00 0.00 0.00 0.00 7.8 0.00 2.33 0.00 0.33 2.00 0.00 14.8 0.00 3.00 0.00 0.00 0.00 0.00 21.8 0.00 5.67 0.00 0.00 4.00 0.00 28.8 0.33 5.00 0.33 0.00 3.33 0.00 4.9 0.00 3.67 0.33 0.33 4.00 0.00 11.9 0.00 4.00 0.00 1.00 2.67 0.00 18.9 0.00 2.00 0.00 0.00 0.67 0.00 25.9 0.00 6.00 0.33 0.00 1.00 0.00 2.10 1.00 5.33 0.67 0.33 1.67 4.00 9.10 0.00 5.00 0.00 0.00 2.00 0.00 16.10 0.00 1.00 0.00 0.33 3.00 0.00 23.10 0.00 2.00 0.00 0.00 3.67 0.00 30.10 0.00 2.67 0.67 0.00 2.00 0.00 6.11 0.00 1.33 0.00 0.33 3.33 0.00 0.67 3.00 0.00 13.11 0.00 1.33 0.00 0.00 1.00 0.00 0.00 1.67 0.00 20.11 0.00 0.33 0.00 0.33 2.00 0.00 0.00 1.00 0.00 27.11 1.00 2.00 0.00 0.33 1.33 0.33 0.33 2.00 0.33 4.12 0.33 1.00 0.33 0.00 1.67 0.00 0.00 0.67 0.00 11.12 0.00 0.33 0.00 0.67 0.67 0.00 1.00 1.00 0.00 18.12 0.00 0.67 0.00 0.00 0.00 0.00 0.67 0.67 0.33 25.12 1.67 0.67 1.33 1.67 0.00 3.67 0.00 1.33 0.00

* Chry. = Chrysoperla sp., and Spid. = Spiders

g Table 17. The pre-oviposition, incubation and nymphal durations (days) and the percentage nymphal mortality of Urentius hystricellus on eggplant (Solanum melongena) and "Gubbien" (Solanum dubium), under laboratory conditions in Khartoum, during autumn (August – September) and winter (January – February) seasons, 2001 / 2002.

Pre-oviposition period Incubation period Mean nymphal duration Season / Total No. % Host Range X ± S.E. Range X ± S.E. 1st. 2nd. 3rd. 4th. 5th. nymphs Mortality Range X ± S.E. used Autumn: Eggplant 1.0-2.0 1.50 ± 0.24 4.5 - 5.5 4.93 ± 0.10 1.95 1.12 1.02 1.23 2.18 7.0 - 8.0 7.50 ± 0.15 28 14.29 "Gubbien" 1.0-2.0 1.50 ± 0.24 4.0 –5.0 4.70 ± 0.12 1.78 1.35 1.13 1.12 2.08 7.0 - 7.5 7.40 ± 0.10 40 10.00 Winter: Eggplant 3.0-4.0 3.70 ± 0.20 11.0-12.5 11.87 ± 0.13 3.10 2.07 2.60 2.97 4.33 12.5 - 16.0 14.53 ± 0.28 25 12.0 "Gubbien" 3.0-4.0 3.60 ± 0.19 9.0-11.0 10.10 ± 0.22 2.53 2.00 2.23 2.27 4.27 10.0 - 15.5 12.47 ± 0.42 15 6.67

h Table 18. The pre-oviposition, incubation and nymphal durations (days) and the percentage nymphal mortality of Urentius euonymus on pigeon pea (Cajanus cajan) and "Hambouk" (Abutilon sp.), under laboratory conditions in Khartoum, during autumn (August – September) and winter (January – February) seasons, 2001 / 2002.

Pre-oviposition period Incubation period Mean nymphal duration Season / Host Total No. % Range X ± S.E. Range X ± S.E. 1st. 2nd. 3rd. 4th. 5th. nymphs Mortality Range X ± S.E. used Autumn: Pigeon pea 1.0-2.0 1.60 ± 0.24 5.5 – 6.0 5.67 ± 0.06 1.27 1.18 1.25 1.27 2.48 7.5 - 9.0 7.95 ± 0.14 57 17.54 "Hambouk" 1.0-2.0 1.50 ± 0.24 5.5 – 7.0 6.07 ± 0.08 1.62 1.20 1.15 1.23 2.23 7.0 – 9.0 8.00 ± 0.21 67 28.36 Winter: Pigeon pea 3.5-4.5 4.00 ± 0.16 12.0– 14.0 13.40 ± 0.18 3.70 2.27 2.30 3.20 5.10 14.5 - 18.0 16.21 ± 0.33 22 13.64 "Hambouk" 3.5-5.0 4.10 ± 0.24 12.0– 14.0 13.20 ± 0.14 3.33 1.73 1.90 2.57 4.53 12.0 - 16.5 13.93 ± 0.51 15 13.33

i Table 19. The pre-oviposition, incubation and nymphal durations (days) and the percentage nymphal mortality of Galeatus scrophicus on sunflower (Helianthus annus) and "Moleita" (Lactuca sp.), under laboratory conditions in Khartoum, during autumn (October– Novemder) and winter (January – February) seasons, 2001 / 2002.

Pre-oviposition period Incubation period Mean Nymphal Duration Total No. Season / Range X ± S.E. Range X ± S.E. 1st. 2nd. 3rd. 4th. 5th. Nymphs % Host Range X ± S.E. Used Mortality Autumn: Sunflower 2.0 – 3.0 2.60 ± 0.24 6.0 - 7.0 6.37 ± 0.11 1.70 1.05 1.17 1.33 2.23 7.0 - 9.0 7.75 ± 0.20 15 6.67 "Moleita" - - - - 1.67 1.17 1.17 1.30 2.30 7.5 – 9.0 7.80 ± 0.30 15 6.67 Winter: Sunflower 4.0 - 5.0 4.80 ± 0.20 10.0 - 12.0 10.77 ± 0.22 3.13 2.20 2.43 2.47 4.47 13.5 - 16.0 14.50 ±0.30 15 20.00 "Moleita" - - - - 3.33 2.50 1.50 2.83 4.33 14.0 - 15.5 14.67 ±0.44 5 0.00

j Table 36. The weekly population means (per 25 plants) of different predators encountered on Zea mays, during two years (2001 – 2002) of surveys in Shambat area.

Predators 2001 2002 Coccinellids Coccinellids Date Hip. Cyd. C.U. Scy. Total Chry. Man. Syr. Spid. Hip. Cyd. C.U. Scy. Total Chry. Man. Syr. Spid. 2 / Jan. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.00 0.00 0.00 0.00 0.00 0.00 10.00 0.00 1.00 0.67 9.1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.00 0.00 0.00 0.00 0.00 0.00 4.00 0.00 0.00 0.00 16.1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.00 0.00 0.00 0.00 0.00 0.00 2.67 0.00 0.00 0.67 23.1 ------0.67 0.00 0.00 0.00 0.67 5.67 0.00 0.00 0.00 30.1 ------1.00 0.00 0.00 0.00 1.00 3.00 0.00 0.67 1.67 6.2 ------0.00 0.00 0.00 0.00 0.00 1.67 0.00 0.00 2.00 13.2 ------0.33 0.00 0.00 0.00 0.33 2.67 0.00 2.67 0.33 20.2 ------6.00 0.00 0.00 0.00 6.00 1.67 0.00 0.00 0.33 27.2 ------8.00 0.00 2.00 0.33 10.33 9.00 0.00 1.00 1.67 6.3 20.67 0.33 0.67 0.00 21.67 2.00 0.00 0.33 0.00 6.67 0.00 2.67 0.00 9.34 19.67 0.00 0.00 1.00 13.3 28.67 1.00 0.67 0.00 30.34 0.00 0.00 0.00 0.67 23.67 0.00 4.67 0.00 28.34 19.00 0.00 0.00 0.00 20.3 ------39.33 0.33 8.00 0.33 47.99 4.33 0.00 0.67 0.67 27.3 10.67 4.00 1.67 0.00 16.34 3.00 0.00 0.00 2.00 41.00 0.33 4.00 0.33 45.66 5.00 0.00 1.00 2.00 3.4 48.00 0.00 0.00 27.00 75.00 0.00 0.67 0.00 0.00 34.67 0.00 2.67 0.00 37.34 3.67 0.00 0.00 1.67 10.4 31.00 0.00 1.00 2.00 34.00 5.00 0.00 0.33 1.33 22.00 0.00 0.33 0.33 22.66 0.00 0.00 0.00 1.00 17.4 26.00 0.00 0.00 1.00 21.00 6.00 0.00 0.00 2.00 17.00 0.00 1.00 0.67 18.67 2.00 0.00 0.00 1.67 24.4 18.67 0.00 0.67 0.67 20.01 0.00 0.00 0.00 1.67 11.33 0.00 0.00 1.00 12.33 0.67 0.00 0.00 1.00 1.5 5.67 0.00 0.67 1.67 8.01 0.00 0.00 0.00 5.67 13.00 0.00 0.00 0.00 13.00 1.00 0.00 0.00 1.00 8.5 1.00 0.00 0.00 0.00 1.00 0.00 0.67 0.00 6.00 ------15.5 5.00 0.00 0.00 0.00 5.00 0.00 0.00 0.00 4.00 ------22.5 ------29.5 ------5.6 ------12.6 ------19.6 ------26.6 ------3.7 ------10.7 16.00 0.00 0.00 0.00 16.00 0.00 0.00 0.00 1.00 ------

k Predators 2001 2002 Coccinellids Coccinellids Date Hip. Cyd. C.U. Scy. Total Chry. Man. Syr. Spid. Hip. Cyd. C.U. Scy. Total Chry. Man. Syr. Spid. 17.7 10.00 0.00 0.00 0.00 10.00 1.00 0.00 0.00 1.00 ------24.7 ------31.7 ------7.8 ------14.8 ------21.8 ------28.8 ------4.9 ------11.9 ------18.9 0.67 37.00 0.00 10.00 47.67 4.67 0.00 0.67 2.00 ------25.9 0.00 9.67 0.00 1.67 11.34 0.00 0.00 0.00 0.67 ------2.10 2.00 12.00 0.00 2.00 16.00 3.00 0.00 0.00 2.00 ------9.10 3.00 17.00 0.00 1.00 21.00 3.00 0.00 0.33 1.67 ------16.10 9.00 28.00 0.00 0.00 37.00 0.00 0.00 0.00 1.00 ------23.10 4.00 13.00 0.00 3.00 20.00 4.00 0.00 0.67 1.67 ------30.10 2.00 3.00 0.00 9.00 14.00 3.00 0.00 5.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.67 6.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.00 0.00 0.00 0.00 0.33 0.33 2.00 0.00 3.00 2.00 13.11 0.00 1.00 0.00 0.33 1.33 0.67 0.00 0.00 1.67 0.00 0.00 0.00 1.00 1.00 1.00 0.00 2.00 1.67 20.11 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 1.00 0.00 0.00 0.00 0.00 0.00 0.67 0.00 0.00 0.00 27.11 0.00 0.33 0.00 0.67 1.00 1.67 0.33 1.00 2.00 0.00 0.00 0.00 0.67 0.67 2.00 0.00 1.67 2.00 4.12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.33 0.00 0.33 0.66 1.67 0.00 1.00 1.67 11.12 0.00 0.00 0.00 0.33 0.33 1.33 0.00 0.67 0.33 0.00 0.00 0.00 0.67 0.67 0.67 0.00 0.00 0.67 18.12 0.33 0.00 0.00 0.33 0.66 2.00 0.00 0.33 9.00 0.00 0.00 0.00 0.33 0.33 1.00 0.00 1.67 0.67 25.12 0.00 0.00 0.00 0.67 0.67 1.00 0.00 1.67 3.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

* Hip. = Hippodamia sp.; Cyd. = Cydonia sp.; C.U. = Coccinella undecimpunctata; Scy. = Scymnus spp.; Chry. = Chrysoperla sp.; Man.= Mantids; Syr = Syrphids and Spid. = Spiders . = Nymphs.

l

350

300

250

200 2000 2001 150 2002

100 Mean No

50

0 Jan. Feb. March April May June July Aug. Sep. Oct. Nov. Dec. Months

Fig. 24. The monthly mean counts of Urentius hystricellus on "Gubbein" (Solanum dubium), during three consecutive years (2000 – 2002) of surveys, in Shambat area.

m

120

100

80

60 2000 2001 Mean No. 40 2002

20

0 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Month

Fig. 25. The monthly mean counts of Urentius euonymus on pigeon pea, during three consecutive years (2000 – 2002), at Shambat.

n

7

6

5

4 2000 3 2001 Mean No 2002 2

1

0 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Months

Fig. 27. The monthly mean counts of predators encountered on "Gubbein" (Solanum dubium), during three consecutive years (2000 – 2002) of surveys in Shambat area.

o

3.5

3

2.5

2 2000 1.5 2001 Mean No 2002 1

0.5

0 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Months

Fig. 28. The monthly mean counts of predators on pig peon pea, during three consecutive years (2000 – 2002), at Shambat.

p

700

600

500

400 Mean No. 2000 300 2001 2002 200

100

0 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Months

Fig. (26). The monthly mean counts of Urentius euonymus on "Hambouk" (Abutilon spp.), during three consecutive years (2000 – 2002) of surveys in Shambat area.

q

30

25

20

15 2001

Mean No 2002 10

5

0 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Months

Fig. 30. The monthly mean counts of total predators encountered on Medicago sativa, during two years (2001 – 2002) of surveys in Shambat area.

r

40

35

30

25

20 2001

Mean No 15 2002

10

5

0 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Months

Fig. 31. The monthly mean counts of total predators encountered on Abu 70" (Sorghum bicolor), during two years (2001 – 2002) of surveys in Shambat area.

s Table 1. List of the lace bug species and their host plants encountered during the study period (2000 – 2002) in Shambat area

Host plant(s) Lace bug species Species Family Notes 1. Eggplant lace bug 1. Eggplant (Solanum melongena L.)* Solanaceae (Urentius hystricellus 2. "Gubbein"(Solanum dubium Fersen.)* Solanaceae Richter) (Fig. 1) 3. "Gibain El Bagr"(Solanium incanum L.)1 Solanaceae 1 This host was only reported from Northern 2. "Adasi" lace bug 1. Pigeon pea (Cajanus cajan (L.) Huth.)* Fabaceae State where it is locally (Urentius euonymus 2. "Hsmbouk"(Abutilon spp.)* Malvaceae called "Kadrabas" Distant) (Fig. 6) 3. "Um Shidaida"(Sida alba L.)* Malvaceae 4. "Taroob"(Chrozophora plicata (Vahl.) A. Juss. Euphorbiaceae Ex Spreng. 5. "Adana"(Rhynchosia memnonia (Del.) DC.) Fabaceae

3. "Sunflower" lace 1. Sunflower (Helianthus annus L.)* Compositae bug (Galeatus 2. Lettuce (Lactuca sativa L.) Compositae scrophicus Saunders) 3. "Moleita" (Sonchus cornutus Hochst. Ex Oliv. + Compositae (Fig. 12) Hiern) 4. "Moleita"(Sonchus oleraceus L.) Compositae 5. "Moleita (Lactuca taraxifolia (Willd.) Schumach) Compositae 6. "Rantouk" (Xanthium brasilicum Vell.) Compositae 7. "Rihan ElGadawil" (Pluchea diosecoridis (L.) DC.) Compositae

t Host plant(s) Lace bug species Species Family Notes 4. "Rehan" lace bug 1. "Rehan" (Ocimum basilicum L.) Labiatae 2 Compared with Cochlochila (Cochlochila sp.)2 bullita (Stal), which found in (Fig. 14) many African countries, as 5. "Adana" lace bug 1. "Adana" (Rhynchosia memnonia (Del.) Fabaceae the only species infesting O. (Fig. 15) DC.) basilicum (Drake and 6. Thaumamannia 1. "Adana" (Rhynchosia memnonia (Del.) Fabaceae Ruhoff, 1965) sp.3 (Fig. 16) DC.) 3Compared with 7. "Sidir" lace bug 1. "Sidir" (Ziziphus spina. christi (L.) Desf.) Rhamnaceae Thaumamannia manni Drake (Monosteira sp.)4 and Davis, recorded without (Fig. 17) 1. "Guddeim" (Grewia tenax (Forsk.) Fiori) host plants in Bolivia, as 8. "Guddeim" lace Tiliaceae drown by Drake and Ruhoff bug (Fig. 19) 1. "Andrab" (Cordia sinensis L.) (1965). 9. "Andrab" lace bug Boraginaceae 4 Compared with Monosteiria (Fig. 21) minutula Montandon, the only species reported on this tree in many African countries (Drake and Ruhoff, 1965).

* Lace bugs from No. 1-3 were the known species, while the rest six were new records. * The six hosts denoted with asterisk were the known species, while the rest were new records

u

Species Host plants Distribution Reference Urentius hystricellus (see text) Richter (Say.) e.g. sycamore (Platanus sp.); ash U.S.A; Canada Shetlar, 1991 (sycamore lace bug) (Fraxinus sp.); hickories (Carya spp.), and London planetree. e.g. Amelanchier spp.; Cotoneaster sp.; U.S.A; Canada; Mexico Shetlar, 1991 (Fitch) (hawthorn lace Crataegus spp.; pyracantha, crabapple; bug) flowering quince; mountain ash; hawthorn ...etc. (Say) e.g. oak (Quercus spp.) U.S.A; Canada Shetlar, 1991 (oak lace bug) e.g Gossypium sp.; Annona spp.; Hibiscus U.S.A; Jamica; Haiti; Cuba; Drees and John, 1999 (Fabricius) (cotton lace spp.; Solanum sp.; Citrus sp.; … etc. Netherlands; Colombia; bug) Mexico, … etc. tiliae (Walsh) e.g. Tilia spp.; Prunus sp.; Cercis sp., U.S.A; Mexico; Canada Shetlar, 1991 (basswood lace bug) Lindens … etc. Habrochila placida Horv. e.g. Coffee, especially robusta Kenya; E. Africa, Zaire; Hill, 1983 (coffee lace bug) Burundi; Rwanda, Habrochila ghesquierei e.g. Coffee, especially arabica Kenya; E. Africa, Zaire; Hill, 1983 Schout. (coffee lace bug) Burundi; Rwanda, Leptobyrsa decora Drake e.g. Lantana camara; Citrus aurantium Colombia; Ecuador; … etc Drake and Ruhoff, 1965 + Misra, 1985

v Galeatus scrophicus (see text) Saunders Pseudacysta perseae e.g avocado (Persea sp.); camphor e.g. U.S.A.; Mexico; Drake and Ruhoff, (Heidemann) (avocado (Cinnamomum sp) Dominicans 1965 lace bug) e.g. Rhododendron spp. (including Japan; China; Germany; Drake and Ruhoff, (Scott) (azalea lace bug) azalea); Kalmia sp.; Pieris sp.; England; Morocco; U.S.A.; 1965 + Shetlar, 1991 Australia, … etc. Stephanitis rhododendri e.g Rhododendron spp.; Kalmia spp.; Netherlands; Germany; Drake and Ruhoff, Horvath (rhododendron Pieris spp.; mountain laurels; fetter-bush England; South Africa; 1965 + Shetlar, 1991 lace bug) … etc. Canada; U.S.A.; … etc. Drake e.g. Andromeda sp.; Aperula sp.; Lindera Japan; India; U.S.A. Drake and Ruhoff, and Maa (andromeda lace spp.; Cinnamomum sp.; Lyonia sp.; Pierus 1965 + Shetlar, 1991 bug) spp.; Salix sp.; Styrax sp.; … etc. Stephanitis typica (Dist.) Main host: bananas. Alternate hosts: Ceylon; India; Pakistan; China; Drake and Ruhoff, (banana lace bug) cocconut; cardamom; manila hemp; Japan; Taiwan; Philippine … 1965 + Hill, 1983 Alpinia spp.; and others. etc. e.g Lantana spp. (e.g. L. camara); Lippia Peru; Brazil; Colombia; Drake and Ruhoff, Stal (lantana lace bug) sp.; Callirhoe sp.; Myoporum sp.; U.S.A.; Cuba; Haiti; 1965 + Cilliers, 1987 Xanthium sp.; ebony. Netherlands; Mexico; a, b Australia; India and others

w

Fig. 16. Thaumamannia sp. collected from Rhynchosia memnonia; a) Adult b) Last instar nymph

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Fig. 29. The monthly mean counts of predators encountered on “Hambouk” (Abutilon spp.), during three consecutive years (2000 – 2002) of surveys in Shambat area.

y