Morphology and Economic Importance of the Cotton Seed Bug hyalinipennis Costa (: )

By Munhul Hassan Mokhtar B.Sc. (Agric) Honours, University of Khartoum 2005

A thesis Submitted to the University of Khartoum in Partial Fulfillment of the Requirements for the Degree of M.Sc.In Crop Protection

Supervisor, Dr. Elwasila Guddoura Mohamed

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Department of crop protection Faculty of Agriculture University of Khartoum August 2009

DEDICATION

To my beloved family Dear mother, father , brother and sister… To the Soul of my dear friends…. I dedicate this work.

Munhul

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ACKNOWLEDGEMENTS

First of all, I render my thanks and praise to Almighty Allah, who offered me all things to accomplish this work.

I am deeply indebted and grateful to my supervisor Dr. Elwasila Guddoura

Mohamed for his continuous guidance, valuable advice throughout this study. I would like also to express my thank and appreciation to Dr.Abdel Wahab Hassan

Abdallah for his great help in statistical analysis. My thanks are also extended to all members of the department of crop protection and postgraduate students in

Faculty of Agriculture, University of Khartoum for their continuous consideration and interest. Infinite gratitude and appreciation are due to my family and relatives

and all those who helped me in one way or another especially Mr.Emad Ismail, Mr.

Atef Abdel Rahim, and Mr. Ismail Awad for their moral support.

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LIST OF CONTENTS

Page Dedication i Acknowledgements ii List of Contents iii List of Tables v List of Figures vi List of Plates vii English Abstract viii Arabic Abstract x 1. Introduction 1 2. Review of literature 4 2.1The cotton seed bug 4 2.1.1 Classification 4 2.1.2 Taxonomic position 5 2.1.3 Geographical Distribution 5 2.1.3.1 Distribution in Sudan 7 2.1.4 Description: Morphology 8 2.1.4.1 The adult (general) 8 (i)The Adult male 8 (ii)The Adult female 10 2.1.4.2 The egg 13 2.1.4.3 The nymph (general) 13 (1) First nymphal instar 13 (2) Second nymphal instar 14 (3)Third nymphal instar 14 (4)Fourth nymphal instar 14 (5)Fifth nymphal instar 14 2.1.5 Biology (life history) 16 (a) Egg stage 16 (b) Nymphal stages 17 (c)Adult stage 17 2.1.6 Ecology 20 2.1.7 Host plants 21 2.1.7.1 Host Preference 24 2.1.8 Nature and extent of damage 25 2.1.8.1 Damage to the seeds 26 2.1.8.1.1 Effect in germination 26 2.1.8.1.2Effect of damage in seed weight 27

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2.1.8.1.3 Effect in seed contents 27 2.1.8.2 Damage to the lint 27 2.1.9. Control 28 2.1.9.1 Cultural control 28 2.1.19.2 Chemical control 29 2.1.9.3 Biological control 31 2.1.9.3.1 Natural Enemies 31 2.1.9.3.2 Fungus 32 3. Materials and methods 33 3.1. Filed survey 33 3.2. Morphological studies 33 3.3. Effect of Bug feeding on seed quality 34 3.4. Statistical Analysis 36 4. Results 37 4.1Morphological study 37 4.2. Seed weigh 37 4.3. Seed germination rate 37 4.4. Seed Oil content 46 4.5. Seed Nitrogen content 46 4.6. Seed Protein content 46 5. Discussion 53 6.References 56

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LIST OF TABLES

Page

Table 1: List of potential and alternative host plants of the cotton 22 seed bug, Costa

Table 2: Host plants of Oxycarennus hyalinipenis Costa in 23 Shambat Area

Table 3: The length of the total body of (mm) of the cotton 38 seed bug Oxycarenus hyalinipennis Costa

Table 4: The length of the antennae (mm) of the cotton seed bug 39 Oxycarenus hyalinipennis Costa

Table 5: The length of the legs (mm) of the cotton seed bug 40 Oxycarenus hyalinipennis Costa

Table 6: The length of the forewing /hind wing (mm) of the 41 cotton seed bug Oxycarenus hyalinipennis Costa

Table 7: Effect of bug feeding on the weight of cotton seeds/mg 42

Table 8: Effect of bug feeding on the rate of germination of 44 Cotton seeds

Table 9: Effect of bug feeding on the oil Content of cotton seeds 47

Table 10: Effect of bug feeding on the Nitrogen Content of cotton 49 seeds

Table 11: Effect of bug feeding on the Protein Content of cotton 51 seeds

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LIST OF FIGURES

Page

43 Figure 1: Effect of bug feeding on the weight of cotton seeds/mg

45 Figure 2: Effect of bug feeding on the germination rate of cotton seeds

48 Figure 3: Effect of bug feeding on the oil Content of cotton seeds

50 Figure 4: Effect of bug feeding on the Nitrogen Content of cotton seed

52 Figure 5: Effect of bug feeding on the Protein Content of cotton seeds

و

LIST OF PLATES

Page

Plate 1.A: The adult male stage of Oxycarenus hyalinipennis Costa 12

Plate 1.B: The adult female stage of Oxycarenus hyalinipennis Costa 12

Plate 2: The nymphal stages of Oxycarenus hyalinipennis Costa 15

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ABSTRACT

The cotton seed bug, Oxycarenus hyalinipennis Costa (Hemiptera,

Oxycarinidae) is a serious pest of malvaceous plant in Sudan .In the present studies, and under laboratory conditions, attempts were made to investigate some aspects regarding external morphology of the said species. However description of the external morphology of the adult stage was given as well the morphological features of the adult bug by which the two sexes could be separated were indicated

. Thorax, head, antennae, and femora are black and the wings are transparent. The average length of adults female and male measured 4.3 and 3.8 mm respectively

.The average length of the antennae ,legs , the forewings and hind wings were as follows : 1.849; 1.8, 1.8, 1.6 mm respectively in the male and 2.21, 1.9, 2.1, 1.7 mm respectively in female .

Both Nymphs and adults suck the cotton seed contents, resulting in light- weight seeds and decreased the germination rate and oil, protein and nitrogen contents .The estimated damage was found to be 2.3% and 3.7% for seed weight and germination rate respectively. The reduction in oil, Protein and Nitrogen contents was 6.3 %, 12.5 % and 19.5% respectively.

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A fungus has been found growing on the infested seeds by high rate compared with non-infested seeds during the germination test. The species that have been identified in the laboratory were Aspergillus flavus; Micillium.sp and

Fusarium .sp.

ط

اﻟﻤﺴﺘﺨــــــــﻠﺺ

ﺒﻕ ﺒﺫﺭﺓ ﺍﻟﻘﻁـﻥ Oxycarenus hyalinipennis Costa (ﺭﺘﺒـﺔ ﻨﺼـﻔﻴﺔ ﺍﻷﺠﻨﺤـﻪ : ﻋﺎﺌﻠـﺔ

Oxycarinidae) ﻤﻥ ﺍﻵﻓﺎﺕ ﺍﻟﻬﺎﻤﻪ ﺍﻟﺘﻲ ﺘﺼﻴﺏ ﺍﻟﻌﺎﺌﻠﺔ ﺍﻟﺨﺒﺎﺯﻴﻪ ﻓﻲ ﺍﻟﺴﻭﺩﺍﻥ .

ﻓﻲ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﻪ ﻭ ﺘﺤﺕ ﺍﻟﻅﺭﻭﻑ ﺍﻟﻤﻌﻤﻠﻴﻪ ﺘﻤﺕ ﺩﺭﺍﺴﺔ ﺍﻟﺸﻜل ﺍﻟﻅﺎﻫﺭﻱ ﻟﻠﻨﻭﻉ ﺍﻟﻤﺫﻜﻭﺭ ،

ﻭﺘﻨﺎﻭﻟﺕ ﺍﻟﺩﺭﺍﺴﺔ ﺍﻟﻭﺼﻑ ﺍﻟﻌﺎﻡ ﻭﺍﻟﺸﻜل ﺍﻟﻅﺎﻫﺭﻱ ﻟﻠﻁﻭﺭ ﺍﻟﺒﺎﻟﻎ ﻭ ﺃ ﻴ ﻀ ﺎﹰ ﺍﻟﺼﻔﺎﺕ ﺍﻟﻅﺎﻫﺭﻴﻪ ﺍﻟﻤﻤﻴﺯﻩ ﻟﻠﺠﻨﺱ .

ﺍﻟﺼﺩﺭ،ﺍﻟﺭﺃﺱ،ﻗﺭﻭﻥ ﺍﻹﺴﺘﺸﻌﺎﺭ ﻭﺍﻷﺭﺠل ﺴﻭﺩﺍﺀ . ﺍﻷﺠﻨﺤﻪ ﺸﻔﺎﻓﺔ ﺍﻟﻠﻭﻥ . ﻤﺘﻭﺴﻁ ﺍﻟﻁﻭل ﻟﻸﻨﺜﻰ ﻭﺍﻟـﺫﻜﺭ

ﺍﻟﺒﺎﻟﻐﻴﻥ 4.3 ﻭ3.8 ﻤﻠﻡ ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻲ .ﻤﺘﻭﺴﻁ ﺍﻟﻁﻭل ﻟﻘﺭﻭﻥ ﺍﻹﺴﺘﺸﻌﺎﺭ ، ﺍﻷﺭﺠل ، ﺍﻷﺠﻨﺤﻪ ﺍﻷﻤﺎﻤﻴـﻪ ،

ﺍﻷﺠﻨﺤــﻪ ﺍﻟﺨﻠﻔﻴــﻪ ﻜــﺎﻵﺘﻲ : 1.8- 1.8- 1.8- 1.6 ﻤﻠــﻡ ﻓــﻲ ﺍﻟــﺫﻜﺭ ﻋﻠــﻰ ﺍﻟﺘــﻭﺍﻟﻲ ﻭﺒﻘﻴــﺎﺱ

2.21/1.9/2.1/1.7 ﻤﻠﻡ ﻓﻲ ﺍﻷﻨﺜﻰ ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻲ . ﺘﻤﺘﺹ ﺍﻷﻁﻭﺍﺭ ﺍﻟﺒﺎﻟﻐﻪ ﻭﺍﻟﺤﻭﺭﻴـﺎﺕ ﻤ ﻌ ـ ﺎﹰ ﻤﺤﺘﻭﻴـﺎﺕ

ﺍﻟﺒﺫﻭﺭ ﻭﻴﻨﺘﺞ ﻋﻥ ﺫﻟﻙ ﻨﻘﺼﺎﻥ ﻓﻲ ﻭﺯﻥ ﻭ ﻤﻌﺩل ﺇﻨﺒﺎﺕ ﺍﻟﺒﺫﻭﺭ ﺒﻨﺴﺒﺔ 2.3 % 3.7% ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻲ ، ﻜﻤﺎ

ﺘﻘﻠل ﺍﻹﺼﺎﺒﻪ ﺒﺎﻟﺒﻕ ﻤﻥ ﻤﺤﺘﻭﻯ ﺍﻟﺒﺫﻭﺭ ﻤﻥ ﺍﻟﺯﻴﺕ ﻭﺍﻟﺒـﺭﻭﺘﻴﻥ ﻭﺍﻟﻨﺘـﺭﻭﺠﻴﻥ ﺒﻨﺴـﺒﻪ 6.3 %- -%12.5

19.5% ﻋﻠﻰ ﺍﻟﺘﻭﺍﻟﻲ .

ﻭﺠﺩﺕ ﻨﻤﻭﺍﺕ ﻓﻁﺭﻴﻪ ﻋﻠﻰ ﺍﻟﺒﺫﻭﺭ ﺍﻟﻤﺼﺎﺒﻪ ﺒﻤﻌﺩل ﻋﺎﻟﻲ ﻤﻘﺎﺭﻨﺔﹰ ﺒﺎﻟﺒﺫﻭﺭ ﺍﻟﺴﻠﻴﻤﻪ ﺃﺜﻨﺎﺀ ﺇﺨﺘﺒﺎﺭ ﺍﻹﻨﺒﺎﺕ ﻭﺘـﻡ

ﺍﻟﺘﻌﺭﻑ ﻤﻌﻤﻠﻴﺎﹰ ﻋﻠﻰ ﺍﻷﻨﻭﻉ Aspergillus flavus ; Micillium.sp and Fusarium sp

ي 1. INTRODUCTION

In some countries, cotton is a major cash crop and it is a basis for national textile industry and a source of foreign exchange. It is primarily grown as a fiber crop for lint. The principle products of cotton seed is the oil the cake, which is a good source of feed, and also useful manure.

As the world population is increasing, the demand for natural cotton fiber continues to increase. Today the crop is grown in over 60 countries, on a total of almost 32.4 million hectares, which represents approximately

2.5%, of all cultivated land (Mathews, 1989).

In Sudan, cotton is widely grown. It ranks almost first among the main cash crops .The two commercial species cultivated are: the long staple,

Gossypium barbadense. L. and the short staple, hirsutum L. The area under cotton in the season 1989/90 was about 791.000 feddans

(feddan= 1.038 acres), about 67.000 feddans were under rain cultivation.

The total production of the above area was 308.400 ton of cotton seed

(Atem, 1993).

The production of cotton in the Sudan is affected by decreasing its yield, grade and increasing its cost of production. Among the main reasons is the infestation of the insect pests which considered to be the most serious.

More than a dozen of different species attack the cotton crop. Each of these

1 species is capable of causing economic yield loss. Annual losses in cotton yield due to insect damage had been estimated as 20% (Gaines, 1967).

Insects attack cotton start early in the season and continue until the pulling of the cotton sticks.

A number of Hetropterous are associated with the cotton crop in different parts of the world .Three groups of these insects stand out above the rest as regards their economic importance, namely, various species of

Pentatomidae, or shield bugs, the genus Dysidercus (Pyrrhocoridae), or cotton stainers and the genus Oxycarenus ()or cotton seed bug .Of these the last one has up to the present received comparatively little attention from entomologists; indeed it is probably no exaggeration to say that of no other widespread and abundant pest of any such commercially important plant as cotton.

The cotton seed bug, Oxycarenus hyalinipennis Costa is found in all cotton growing areas. Although it is a most serious pest of mature cotton, its attack continues until harvesting time (Sween, 1956; Diab, 1968;

Schumutterer, 1969 and Guddoura, 1977) . However Morrill (1910) was the first who recorded the damage by Oxycarenus.

2 The objectives of this work were to study the external morphology of the species and the effect of the pest feeding on the weight and germination rate of seeds as well as the seed quality, (oil, protein, and nitrogen contents).

3 2. REVIEW OF LITERATURE

2.1 The cotton seed bug

The cotton seed bug, Oxycarenus hyalinipennis Costa (Hemiptera,

Lygaeidae) is a serious pest of malvaceous plants in the Sudan. It is among the late season insect pests, confining its attack to the ripen seeds of cotton and other malvaceous plants such as , esculents; Roselle,

Hibiscus sabdariffa and Kenai, Hibiscus cannabinus (Gameel, 1967) Other pests on cotton include: aphids, white flies, boll worms, thrips, stainers bugs and mites.

This pest not only feeds on other plants of the order Malvacae, but also on plant in Tiliaceae and Sterculiaceae (Slater & Baranowski 1994). All stages of the species feed solely on the seeds.

2.1.1 Classification

Phylum: Arthropoda

Sub-phylum: Uniramia.

Class: Insecta.

Order: Hemiptera

Sub order Hetroptera

Super family: Lygaeoidea

Family: Oxycarinidae.

4 Sub- family: Oxycareninae

Genus: Oxycarenus

Species: hyalinipennis

Author: Costa .

2.1.2 Taxonomic position

Oxycarenus hyalinipennis Costa is a member of the super family

Lygaeoidea, family Oxycarenidae, and sub family Oxycareninae with the

synonymy Aphanus tardus var hyalinipennis. The species was described

from by Costa in 1847 (Henry, 1997).

It is commonly referred to as “the cotton seed bug.” (Slater &

Baranowski 1994); and were collectively known as dusky cotton seed bug

(Pearson, 1958; Odhiambo, 1960).

In Sudan Oxycarenus hyalinipennis Costa is locally known as ”bug

bizrat el gutn” (Ripper and George,1965) ,however the species was till

recently described under the family Lygaeidae, but now it belongs to the

family Oxycarenidae .

2.1.3 Geographical distribution

The cotton seed bug, Oxycarenus hyalinipennis Costa is the most widely distributed species in the world. Various cotton feeding of the genus

5 Oxycarenus, are recorded from , Asia, Australia, and South America, the majority being from Africa. About 36 species of Oxycarenus were listed in Africa by Samy (1969). A few species are mentioned as injurious to plants, other than those of the family (Kirkpatrick, 1923). It was recorded from Egypt, Sudan, Uganda, Congo, Kenya, Tanzania, Angola,

Malawi and a number of other African countries (Schmutterer, 1969).

It is present from Africa to the far East; but does not occur in North and South America. In Far East, it was recorded from Vietnam and the

Philippines, while it was accidentally introduced to Brazil (Pearson; 1958 and Samy; 1969). Morstatt (1914) reported the occurrence of Oxycarenus hyalinipennis Costa in large numbers in East Africa.

Henry (1997) found cotton plants infested cotton by the cotton seed bug, in Matthew town, Great Inagua and Bahamas. Although it has not been reported from North America, but has been intercepted numerous times at

U.S. ports of entry and because it is already established on islands near the

U.S. mainland, its arrival in the U.S. is expected. In the West Indies,

Baranowski & Slater (2005) report it from the Turks and Caicos, Bahamas,

Cayman Islands, and Hispaniola. They stated that: It was not found during a preliminary survey along the entire eastern coast of Florida in 2006,and added that a breeding population of Oxycarenus hyalinipennis Costa is

6 reported for the first time from the West Indies (Baranowski and Slater:

2005).

2.1.3.1 Distribution in Sudan

Oxycarenus hyalinipennis Costa has been known to occur in Sudan at least since 1860 and there seemed to be no grounds for supposing that it is not indigenous to the country.

This insect appears to be abundant throughout lower and Middle

Sudan, in the cotton growing districts. the limiting factor is probably high temperature, i.e. in Gezira state Wad Medani, Khashm -El Grba and other places where cotton is cultivated in large areas (Kirkpatrick:1923) .

Seven species were recorded from Sudan, these were: Oxycarenus hyalinipennis Costa, Oxycarenus rufiventris Gemmar. Oxycarenus feiberi

Stal., Oxycarenus breddini (Bergroth), Oxycarenus izzardi, Stal Oxycarenus alibidipennis Stal., Oxycarenus multiformis . The species occurring on cotton were the first three mentioned above .Other species were found feeding on variable host plants of no economic importance and weeds such as spp.and sp (Samy, 1969; Schumutterer, 1969).

7 2.1.4 Description: Morphology

2.1.4 1The adult (general)

The adult is a small, elongate bug with pointed head , about 4 mm long and 1.5mm broad, dark-brown or black with a dorsally reddish-brown abdomen and translucent hemelytra (Pearson ;1958).The main character that distinguished Oxycarenus hyalinipennis Costa from other species was its dark brown to black antennae, two-third of the basal segments are light to brownish-yellow (Samy,1969).

The hairs on this insect are of three different types, more or less erect, stiff hairs, blot at the tip, where they terminate in from four to seven small teeth; normal straight tapering hairs; and very thin curved flatling tapering hairs (Kirkpatrick, 1923) .

(i) The Adult male (Plate 1A)

- The head: blackish, punctuate clothed with white coronate hairs.

- The mouth: parts piercing and sucking, brownish to black clothed with

short fine hairs.

- The compound eyes: project out considerably from the head, red, slightly

oval in shape, with pair of brighter red ocelli close to the compound eyes.

(Plate 1A)

8 - The antenna: black, with four segments .covered with simple hairs. The

average length 1.8 mm

- The thorax: three segments departed as follows:

(i) Pro- thorax: The pro thorax and scutellum of meso thorax , punctuate ,

black ,some what brownish .

(ii) Meso–thorax: black, shining, covered with a few exceedingly minute

hairs .

(iii) Meta thorax: black and minutely punctuate.

- The wings have a silvery iridescent appearance; the fore wings, or hemi- elytra, are hyaline, brownish at the base, with a small brown spot at the apex of the clavus,the clavus has a row of about twenty-two or twenty-three circular pigmented pits. There is also, median rows of pits which are variable in number, clothed with very fine simple hairs .Membrane very thin hyaline with traces of fire inconspicuous longitudinal veins. The hind wings are exceedingly thin hyaline with slivery appearance during life when seen through the hemi-elytra, venation of the normal type. The total length when fully extended being over 1.1 mm.

- The legs are shining, with the coxae and trochanters brownish, all femora black, Tarsi three jointed.

9 - The rostrum is brownish to blackish often quite black, it is thinly clothed

with short fine hairs, its average length is as 2.34 mm.

- The abdomen is orange brown, darker at side (and middle of the basal

segments). The abdomen is bares on the disc, truncate at the end and

covered with the wings when at rest.

- Venter all side brownish, blacker at the sides, shining on the median area

of the two terminal segments (excluding the genitalia). Thick row of very

fine white simple hairs is present.

- Genitalia is black, terminal segment, clothed with shorter hair .Terminal

pair of claspers strong sickle shaped. The penis consists of a yellowish

brown rod-shaped organ terminating in affine coiled tube, the total length

when fully extended being over 1.1mm.

In studying the male genetalia of the Oxycarenus species, the male adages offered a useful identification feature .The dorsal part of the adages of Oxycarenus hyalinipennis Costa is triangular in shape , while in other species it had variable forms . (Pruthi; 1925; Ashock ,1957) .The average length is 3.7mm .(Atem ,1993) .

(ii) The Adult female(Plate 1B)

It is very similar to the male except in size, the average length being

4.3 mm, the abdomen is truncate at the end. The ovipositor is two-jointed,

10 yellow in color, doubly folded back on the ventral surface of the abdomen and covered by the penultimate ventral sclerites (Plate 1B).The antennal length is 2.115mm. (Kirkpatrick: 1923).

11

( Plate .1.A) The adult Male stage of Oxycarenus hyalinipennis Costa

(Plate.1.B) The adult female stage of Oxycarenus hyalinipennis Costa

12

2.1.4.2 The egg

The freshly laid egg is pale yellow or creamy in color, small and elongate in shape and tapering towards the anterior end. The average dimensions of the egg are 0.9-0.01 mm in length and 0.3-0.2mm in width

.(across its widest part. (ِAtem; 1993

2.1.4.3 The nymph (general).

There are five instars in the nymphal development of

O.hyalinipennis.Costa (Plate.2). When first emerges has beautiful coral pink colour, both on the body and on the antennae and legs, after few hours (the period being shorter when the weather is warm) the colour is entirely changed, and the insect assumes the next colour. All the immature stages are wingless, have only two tarsal joints and no ocelli .The first three instars are very similar except in size (Plate 2).

(1) First nymphal instar

The newly hatched nymph is tiny, light reddish brown in colour, soon after ecolosion nymph became active and aggregate The average measurements of the nymph body are 1.2mm in length and 0.3±0.02 mm in width (Kirkpatrick:1923).

13

(2) Second nymphal instar

This is very similar to the preceding instar,except the size , the average length being 1.58 in length and 0.63±0.05 mm in width The abdomen often becomes dark reddish brown by exposure to the air

(Kirkpatrick:1923) .

(3)Third nymphal instar

It is about 2.3± 0.08 mm long and 0.93 ± 0.07 mm broad ,its colour is fainter at both the anterior and posterior parts , giving it the appearance of two white bands on the thorax , a character that may distinguish it from the two previous instars (Atem, 1993)

(4) Fourth nymphal instar

Wing buds, cover the side margins of the met thorax are present. The average length of this instar is 2.86 mm (Kirkpatrick: 1923).

(5) Fifith nymphal instar

This is the last immature stadium of the insect, when just molted, has coral pink antennae and legs, transparent whitish wing-buds, and a brilliant red abdomen with some traces of pale colour on the basal segments and a few very simple hairs. The length of this stage varies from about 3.28 mm, to 3.65 mm (Kirkpatrick: 1923).

14

(Plate .2) The Nymphal stages

15

2.1.5 Biology (life history)

Studies on the life history of the cotton seed bug were carried out by several workers (Odhiambo, 1957; Abul-Nasr and Samy, 1969;

Schmutterer, 1969; Dimetry, 1971; Hammad et al., 1973; Hill, 1983). The whole cycle from egg to egg may probably be completed in as short a time as twenty days .There are almost three generations but some workers found four generations during the course of one breeding season. Three stages were recorded during the life history: the egg, the nymphal stage and the adult stage.

(a) Egg stage

The eggs are laid very soon after copulation .The average number laid by one female which has fed on cotton is about twenty, deposited singly or in clusters, arranged closely in the grooves of opened cotton bolls, usually among the lint or sometime between the bolls and bracteoles.

The incubation period varies from 3-5 days according to temperature and humidity .At constant temperature, it ranges from about 4 days at 35°C to 43days at 14.6°C .The eggs do not hatch at temperature above 37°C and below 8°C (Pearson,1958) .

16

(b) Nymphal stages

There are five instars in the nymphal development of Oxycarenus hyalinipennis Costa. The average duration of the various instars were

3.81±0.2, 3.6±0.45, 3.6±0.32 and 3.73±0.42 days for the first, second, third, fourth and fifth instars respectively (Atem, 1993) .The nymphal stage was found to last 27-30 days by Odhiambo (1957) in Uganda and it occupied up to 2 weeks (Pearson,1958)and 15 days at 25-32 °C in Egypt (Schmutterer,

1969) .The shortest development was in July and the longest in November-

March.

The duration of all five nymphal stages is two weeks upwards, but there is considerable variation, apart from that caused by temperature.

(c) Adult stage

Copulation occurred within 24 hours of adult emergence in summer; but was delayed 2-3days in winter and the adult dies very shortly after oviposition.The preoviposition period depended on the temperature .It was found to be 1-4 days by Pearson (1958),10.1, 8 and 4.1 day at 3 temperature

:25,30 and 35°C respectively by Hammed et al. (1973) and 2-3 days at average temperature of 26.3°C in July (Abul-Naser and Samy,1969).

The average longevity was 5 days for both sexes of the bug. (Abul-

Nasr and Samy; 1969). In Egypt, the average longevity of the adult male

17 bugs was 34.8, 28.8 and 9.6 days at 25, 30 and 35°C, respectively ; while the Adult female longevity was 42.4, 36, 22.6 days ,respectively (Hammad et al.,1973).

The developmental period of the cotton seed bug , Oxycarenus hyalinipennis Costa, differed according to the type of food and prevailing environmental conditions (Wigglesworth, 1953; Bosvine, 1966, Engelmann,

1970). Okra seeds shortened the nymphal period and increased the number of eggs production .It prolonged the adult longevity and therefore it can be considered the most favorable host plant followed by cotton, roselle and deccan hemp seeds. Okra produced adults of higher egg production than cotton .This due to the fact that the seed coat of okra seed is soft and the bug is able to pierce it with its styles deep and suck the seed nutrients easily.

This probably, favors quick maturation of eggs, while the seed-coat of cotton and other species are comparatively harder (Pearson; 1958).

Dimetry (1973) mentioned that the deccan hemp seeds were the most suitable food in terms of fecundity, longevity and mortality, when compared with cotton, okra, roselle and marrow. The reason for this contradiction was not clear, but it could be explained by the differences in the nutritive value with in the same plants.

18 Oviposition: The total number of eggs laid by a female ranged between 15-40 egg with an average of 20 eggs (Atem,1993) Hammed et al.

(1973) in Egypt came to the same result of egg production as it is in the

Sudan. They stated that the similarity of the weather conditions in both countiers where the experiments were performed is the reason for this.

Schmutterer (1969) gave 25 eggs as the average production per female, while Hammad et al. (1973) reported an average of 90 eggs per female . Typical oviposition behavior of the insect was also reported by

Buxton (1930); Wigglesworth (1953); Pearson (1958); Busvine,

1966;Englemann (1970); Dimetry (1973) and Hill (1983) who reported that, the number of eggs produced often depends on the nutrition of the females, which was suggested to be the most important single factor in the majority of insect species.

Insects seldom oviposit indiscriminately over the surface of the plants; but characteristically deposit their eggs on selected sites (Beck, 1965). The selection of suitable site by the female is of great importance since it must ensure that the eggs are adequately protected from environment and that the correct food would be available for the relatively immobile off-springs when they emerge (Brazzel and martin, 1957; Champman, 1969).

19 2.1.6 Ecology

Cotton fields were being infested with Oxycarenus in October by bugs migrating from Sida sp, and Hibiscus plants growing at the boarder of cotton fields.The infestation was greater at the edge than the center of the field. The population of Oxycarenus latus Kirby was favored by high temperature (35 to 45°C) and moderately high humidity (45 to 60%).

(Odhaimbo, 1957; Thangavelu, 1978). In India, maximum populations of

Oxycarenus hyalinipennis Costa was recorded during September (Ram and

Chopora, 1988).

The cotton seed bug after the harvest passes the dry or dead season in diapause (Pearson, 1958; Schumutterer, 1969). Copulation lasts for four hours or longer, not always continuously; in warm weather it completes with in twenty-four hours (Kirkrpatrick, 1923).

The chemotatic and visual factors may play a role in site selection and subsequent egg laying, O hyalinipennis Costa was found to prefer the open boll cavities and the lint for egg laying, and the cavities provide protection and moisture for egg development and maturation. This will also enables new emerged nymphs to gain access to the mature seeds easily.

Oxycarenus hyalinipennis Costa was found in the bolls of the cotton plants, or in cotton fibers on the outside of the boll .Great majority were

20 found deeper in the boll around the seeds and would emerge when the boll was agitated. Occasionally, these bugs could be found in the leaf litter beneath the cotton plants and even more rarely on the leaves. (Beck; 1965) .

2.1.7 Host plants

The bug is a polyphagus feeder, with a host range mainly belonging to the order Malvaceae; in addition to the members of this order, the bug feeds on plant seeds belong to the order Tileaceae and Sterculiacae (Slater &

Baranowski, 1994)

The most important cultivated host are: Cotton, Okra, Deccan hemp and Roselle .The rest are weeds or ornamental plants. (Pearson,1958)

Odhiambo (1957) observed the bug attacking wild Sida spp. and Hibiscus spp .Samy (1969), Schumutterer, (1969), Thangavelu (1978) and Hill

(1983) confirmed most host plants listed by Kirkpatrick (1923) as hosts in

Egypt (Table 1).

Breeding can only take place when the seeds of one of the host plants are available for food. On cotton it commences as soon as the first bolls open .The first 3 families of the order Malvales (Table.1) are most probably the only true host plants.

The host plants of the bug were surveyed in Shambat locality by the plant species are found recorded in (Table 2), (Atem, 1993).

21 Table (1) List of potential and alternative host plants of the cotton seed bug, Oxycarenus hyalinipennis Costa in Egypt

Serial No Common Name Family 1. Cotton Malvaceae 2. Hambuk " 3. Kapok " 4. Kola " 5. Kenaf " 6. Okra " 7. Roselle " " ــ .8 " ــ .9 " ــ .10 Stericuliaceae ــ .11 " ــ .12 Tiliaceae ــ .13 14. Cashew Anacardiaceae 15. Peaches Rosaceae 16. Apples " Boraginaceae ــ .17 18. Becium Labiatae 19. Potato Solanaceae Compositae ــ .20 21. Lettuce "

22

Table (2) Host plants of Oxycarenus hyalinipennis Costa

in Shambat area (Sudan)

Host plant Scientific name Family

Hambuk Abutilon spp Malvaceae

Cotton Gossypium spp "

Deccan hemp Hibiscus cannabinus "

Roselle Hibiscus Sabdariffa "

Okra Hibiscus esculentus "

Wild Okra (Waika) Hibiscus esculentus "

Wild Okra (Waika) Hibiscus lobatus "

Sakaran Datura stramonium Solanaceae

Egg-plant Solanum melongena "

23 The seed bug was commonly found on cotton Gossypium barbadense which is the main host throughout the growing season. Large numbers of the bug were also recorder on Roselle.

Hibiscus sabdariffa, okra Hibiscus esculentus, deccan hemp, Hibiscus cannabinus and Abutilon sp.

2.1.7.1 Host Preference

The relationship between insect abundance and suitable food is fairly obvious, accelerating their growth, development and reproduction (Roth and

Willis 1950, Busvine, 1966).

The plants chosen by the bug for oviposition correlated which those on which they preferred to feed .Those plants (seeds) on witch the bugs oviposited were also those in which the nymphs could feed and develop to maturity. The largest bug population was found on Okra, which was most preferred by the insect, while deccan hemp was the least preferred and hosted much fewer bugs.

The developmental period of the cotton seed bug, Oxycarenus hyalinipennis Costa differed according to the type of food and prevailing environmental conditions (Wigglesworth, 1953; Busvine, 1966, Engelmann,

1970). Okra seeds shortened the nymphal period and increased the number of egg production. It prolonged the adult longevity and therefore it can be

24 considered the most favorable host. However, the bug host Preference depends on crop maturity, Okra Hibiscus esculents being an early maturing plant was more attractive to the bug than the other host plant followed by cotton, roselle and deccan hemp seeds (Atem, 1993).

Dimetry (1973) mentioned that the deccan hemp seeds were the most suitable food in terms of fecundity, longevity and mortality, when compared with cotton, okra, Roselle and marrow The reason for this contradiction was not clear, but it could be explained by the differences in the nutritive value with in the same plants. (Atem, 1993).

2.1.8 Nature and extent of damage

The damage cased by Oxycarenus hyalinipennis Costa on cotton was reported by Geering (1953), Odhiamo (1957), Pearson (1958) ,Pollard

(1959),Evans(1964), Schmutterer (1969); Basta (1972); Guddora (1977) and

Hill (1983).They observed that the attack of insect stared right from the boll-opning and continued up to the crop harvest .These insects "suk the sap from the base of the young pods and from the blosoms and thus prevent their development.They attack also the seeds when they are tender, which results in a diminution of the germinative strength and consequently a diminution in the product of the plant. A staining of the lint is also

25 mentioned, but the exact method by which this injury is brought about is un explained (Morrill.28.1910).

2.1.8.1 Damage to the seeds

This insect, like most seed-feeders, is very economical in marked contrast to most leaf-eating insect. It completes it is whole development by eating a protein of seeds larger than the full-grown insect.

The injuries are, affected in one way by all stages of the bug percing the testa of ripe seeds with their setae and extracting the juice of the embryo, it will be convenient to describe them under the following four head:

(i) Damage to tugari (i.e. seed use for oil extraction and the manufacture of

cake by weighting of individual seeds, and consequently of the total crop.

(ii) Damage taqawi (i.e.seeds used for sowing) by causing non-germination.

Injuries to the embryo radical not so severe as to inhibit germination.

2.1.8.1.1 Effect in germination

When the picking has been delayed, the vitality of three quarters of the seed may be destroyed (nitrogen, protein,oil) that effect in the vitality of seeds. Experiments on the germination shows that, in the absence of damage by Oxycarenus hyalinipennis Costa most of seeds complete germination

26 without any problem in 3-4 days compared with the infested seeds which gave lower rat of germination (Kirkrpatrick, 1923).

2.1.8.1.2 Effect of damage in seed weight

The feeding of the bug on the internal contents of the cotton seeds (oil

,protein,nitrogen ,damage to seed lint) makes the seed lighter in weight .The lost in weight increased by the increase of infestation. Loss may reach 2.5-

15% or more of it is weight. (Kirkpatrick, 1923).

2.1.8.1.3 Effect on seed content

The cotton seed bug Oxycarenus hyalinipennis Costa inflicted serious damage on cotton seeds all over the country .It was found that the infestation of the bugs probably cased a total loss in range of 2442 and 1017 tons of oil in the two consecutive season of the years 1974/75 about 2.5%

(Guddora ,1977) . Adults and nymphs suck oil from mature seeds and fluid from leaves of young stems to obtain moisture, according to

(Ananthakrishnan et al., 1982).

2.1.8.2 Damage to the lint

There is no damage done to the lint resulting from the puncture of green bolls, such as occurs when cotton is attacked by “stainers” (Dysdercus

27 spp). Possible damage could consequently only be effected in the following ways:

(a) Staining by the squashing of the bugs during picking.

(b) From the same cause during ginning.

(c) From their excrement.

(d) Dirtying of the fiber by the dried dead bodies.

If the cotton seed bugs are present in sufficient numbers, the cotton fiber becomes stained during processing by the maceration of their bodies.

(Nakache & Klein, 1992).

2.1.9 Control

2.1.9.1 Cultural control

Control measures suggested in Egypt included the reduction of suitable resting sites and trapping of the bug on trees during the resting period .Also sunning and storing the cotton lint under cover reduced the risk of crushing the bug whilst ginning. In a large numbers and are easily accessible, they could be brushed off in a cold morning and stamped into the ground (Pearson, 1958).

Traps made of and put round the edge of a cotton field will collect vast quantities of bugs , but the number of such trap necessary for a large field is a disadvantage (Kirkpatrick, 1923).

28 Other means of control include hand picking, traps of cotton seed in early summer, trap crops of bamia (Okra) or Till, and the removal of all totally damaged bolls at the time of the first picking. Any damage to the lint can be entirely eliminated by speeding the cotton in sun, and the use of loose-meshed sacks, to enable as many as possible of the bugs to escape.

During heavy outbreaks of the bug, the cotton crop should be picked or harvested as quickly as possible, in order to expose the crop for the shortest possible time to the bug attack (Schmutterer, 1969). Early picking may reduce loss (Guddora) 1977.

2.1.9.2 Chemical control

The tendency of the presence of the bug deeper in the boll around the seeds makes effective application of pesticides for control of Oxycarenus hyalinipennis Costa difficult. The insecticides will have very little effect with in these protected environments. During the bug outbreaks, effective control is achieved in some countries with a combination of chemicals that have both contact and systemic properties. These chemicals are recommended as ULV (ultra low volume) sprays applied early in the morning while the insects are less active. (Ananthakrishnan, et al.1982) .

Attempt for chemical control of the bug, particularly on cotton had been mentioned by few workers. Paradham and Satpathy (1953) studied the

29 toxicity of some important insecticides on Oxycarenus. latus in India .They found parathion, BHC and Thiocyanate preparation more toxic than DDT.

In Tunisia some races of Oxycarenus hyalinipennis Costa were resistant to many insecticides including DDT, Carbaryl, Malathion and

Aldrin (Melon and Yana, 1964).

No separate chemical measures taken against the bug in the Sudan, but just kept in check when controlling other major pest as bollworms.

Schmutterer (1969)

Materu and Kattumbura .(1974) reported ULV aerial spray of a mixture of Azordin/DDT on Kenaf to be satisfactory; but the determination of spraying regime for Kenaf pests would need further work on seasonal fluctuation of the pest. The following insecticides were used for the control of the cotton seed bug:

(a) Fenvalerate (Sumicidin 90%) at the rate of 0.6 ml/litre H2O .

(b) Methomyl (Lannate 90%) at the rate of 2.5ml/feddan.

(c) Omethoate (Folimat 80%) at the rate of 150ml/feddan .

(d) Dimethoate+Deltamethrin mixture(DecisD(15 +400 gm/littre )at the

rate of 0.2 litre/feddan.

(e) Neem seed water extract (NS,E),prepared from dried neem seed at

the rate of 1Kg seeds/40 litres H2O/feddan (Atem ; 1993).

30 2.1.9.3 Biological control

2.1.9.3.1 Natural Enemies

This species is entirely free from the attack of any insect parasite .It also appears to be remarkably free from predatory enemies, due no doubt to its un pleasant smell. Birds have never been observed to eat them, nor would a Mantis that had been without food for several days take any notice of them. On one or two occasions ants were seen carrying off dead nymphs; whether they actually killed them or not is uncertain (Kirkpatrick, 1 923).

In India, the predator Triphleps tantilus was once seen to attack the nymphs of Oxycarenu latusbut has never been observed naturally, and could not be induced in the laboratory, to attack any stage of Oxycarenus hyalinipennis Costa.

The Reduviid, Nagusta sp, was observed feeding on Oxycarenus in a cultivated field in Uganda . However, predators were not seen in cotton plots .Also Trombidiid mite was recorded on one occasion (Odhiamo,

1957).The predator Chyposa carenia was seen preying on the last instar nymphs of Oxycarenus hyalinipennis Costa in the laboratory in Egypt

(Dimetry ,1971).

31 2.1.9.3.2 Fungus

Fungus was found growing on the dead bugs. The fungus (Apparently

Aspergillus flavus) Appeared on dead bodies of the insects. Although the presence of this fungus was found to hasten very considerably the rate of mortality, it appeared that this was due not to its being parasitic, but to the numerous minute spores which clogged up the spiracles of the living bugs, and caused death by suffocation (Kirkpatrick, 1923).

32 3. MATERIALS AND METHODES

The present work has been carried out in the Faculty of Agriculture university of Khartoum (Shambat).The demonstration farm at Shambat and the laboratory of the crop protection Department were used to cultivate cotton crop Gossypium hirsutum and investigate the insect specimens respectively.

3.1 Filed survey

Regular visits were made to the field to collect insect specimens as well as infested cotton seeds. For this purpose a big number of cotton bolls were caged with paper bags while others were left for infestation.

3.2 Morphological studies

The insect specimens collected were found inside the bolls of the cotton plants; while some specimens were collected standing on the cotton fibers on the outside of the boll. The majority was found deeper in the boll around the seeds.

To study the morphology of the of the cotton seed bug Oxycarenus hyalinipennis Costa, adults were killed; some were kept dry separately while the other were preserved in 5% Sodium chloride solution. The insects were then washed thoroughly in distilled water to remove all traces of Sodium

33 chloride and dehydrate in series of alcohols, 40, 50, 70 and 95% (5 minutes for each) until they assumed a bright transparent appearance. Dehydration was then continued in two batches of absolute alcohol (5 minutes in each).

The specimens were then gradual transferred into Xylene for clearance and then mounted in slide. To study the external features of the bug colour, specimens were kept in a collection with out any treatment. The following parameters were measured on the random sample of ten insects:

1. The body length (mm).

2. The front wing length (mm).

3. The hind wing length (mm).

4. The legs length (mm).

5. The antennae length (mm).

3.3 Effect of the bug feeding on seed quality

The level of infestation in the cotton at that Site which the samples

(seeds) were collected during this experiment, was highest level in

December. They were found on practically every boll of every cotton plant in the infested area and in some cases with over 30 bugs in a single boll (at

November/December).

The two samples (infested and non-infested seeds) were processed and divided into (3) portions then subjected to the following treatment:

34 (A) For the germination experiment the following method was adopted: All boll worm damaged seeds were removed .The seeds to be tested were mixed, and a sample estimated to contain rather over 1,000 apparently sound seeds was taken, from which all those damaged by boll worms were removed , and their percentage counted as "damaged seeds". Of the remainder, consisting of apparently sound seeds, ten groups of 100 each were counted and weighed, to ascertain the average weight and probable error of the mean weight of 100 seeds and to compare between the weight of healthy and infested seeds.

These thousand (500 infested + 500 non-infested) seeds each were germinated in Petri-dishes containing moist filter papers holding 50 seeds each, between thick felt discs for 4 days. The seeds were considered to have germinated successfully when the radical was healthy and the first leaves appeared. The stale water was drained off and fresh added at intervals of 24 hours during the four days .Those that germinated healthy were collected and calculated daily up to the end of the period .In most samples, a small proportion of seeds was found producing a short radical, under one centimeter in length, but failed to grow any more. The number of such overlooked damaged seeds was found to be very small, rarely exceeding one per cent, and not such as to affect appreciably the average weight of the

35 appreciably sound seeds. Excluding such those which did not germinate were classed as "failed".

(B) A portion of 1000 seeds (500 infested, 500 non-infested). All the boll worm damaged seeds were removed and samples of 1.000 apparently sound seeds were carefully weighed, using Mettler sensitive analytical balance and the results were compared for infested and healthy seeds.

(C) The two infested and healthy samples were analyzed for their Oil,

Protein, and Nitrogen contents.

3.4 Statistical Analysis

The data collected were subjected to statistical analysis, where the T- test was applied for comparing the means of healthy and infested seeds samples.

36

4. RESULTS

The field and laboratory work revealed the following results:

4.1 Morphological study

Males and females have similar coloration, but males are slightly smaller than females. The average length of adults female and male was 4.3 and 3.7 mm respectively, (Table 3).The average length of the antennae, legs, the forewing and hind wing was 2.21, 2.2, 2.1, 1.9 mm respectively in female and 1.84; 1.8, 1.8, 1.6 mm respectively in male. (Table 4,5 and 6 ) .

4.2 Seed weigh

Table 7 and Figure 1, shows consistent decrease in seed weight when comparing infested and healthy seeds. The percentage of loss was found to be as 2.3%.

4.3 Seed germination rate

Statistical analysis showed that there was difference in germination rate between the infested and healthy cotton seeds. Mean germination percentage was 98.2 fore the healthy seeds and 94.6 for the infested seeds.

The average percentage loss of seeds germination was found to be 3.7%

(Table 8 and Figure 2).

37

Table 3: The length of the total body (mm) of the cotton seed bug Oxycarenus hyalinipennis Costa

Replicate Male Female 1. 3.7 4.32 2. 3.69 4.29 3. 3.70 4.27 4. 3.69 4.3 5. 3.72 4.06 6. 3.71 4.3 7. 3.68 4.3 8. 3.73 4.34 9. 3.71 4.25 10. 3.70 4.79 Average 3.703 4.322

38

Table 4: The length of the antennae (mm)of the cotton seed bug Oxycarenus hyalinipennis Costa

Replicate Male Female 1. 1.87 2.30 2. 1.90 2.05 3. 1.89 2.15 4. 1.90 2.10 5. 1.79 1.99 6. 1.91 2.32 7. 1.90 2.25 8. 1.90 2.29 9. 1.89 2.35 10. 1.95 2.30 Average 1.84 2.21

39

Table 5: The length of the legs (mm) of the cotton seed bug Oxycarenus hyalinipennis Costa

Replicate Male Female 1. 1.89 2.30 2. 1.90 2.29 3. 1.90 2.00 4. 1.88 2.10 5. 1.92 1.99 6. 1.89 2.32 7. 1.90 2.25 8. 1.90 2.00 9. 1.89 2.35 10. 1.87 2.30 Average 1.80 2.2

40

Table 6: The length of the forewing /hind wing (mm) of the cotton seed bug Oxycarenus hyalinipennis Costa

Replicate Male Female Forewing Hind wing Forewing Hind wing 1. 1.8 1.59 2.30 1.98 2. 1.75 1.73 2.05 1.89 3. 1.8 1.6 2.15 1.90 4. 1.8 1.6 2.10 1.99 5. 1.77 1.70 1.99 1.95 6. 1.76 1.74 2.32 1.99 7. 1.80 1.60 2.25 1.98 8. 1.80 1.60 2.29 2.10 9. 1.89 1.69 2.35 1.99 10. 1.79 1.69 2.30 1.98

Average 1.8 1.6 2.1 1.9

41

Table 7: Effect of bug feeding on the weight of cotton seeds/mg

Replicate Healthy seeds Infected seeds 1 11.90 11.400 2 11.87 11.354 3 12.10 11.300 4 11.90 10.500 5 12.00 10.900 6 11.90 11.390 7 11.90 11.200 8 11.85 11.347 9 11.90 11.254 10 11.91 11.452

Reduction = 2.3 %

42

12.512.5

1212 g g 11.511.5 1111 HealthyHealthy seeds seeds Weight/m Weight/m 10.510.5 InfectedInfected seeds seeds

1010

9.59.5 1234567891012345678910 CottonCotton seeds seeds FigureFigure 1: 1: Effect Effect of of bug bug feeding feeding on on thethe weight weight of of cotton cotton seeds/mg seeds/mg

43

Table (8) Effect of bug feeding on the germination rate of cotton seeds

Number of Infested seeds tested forHealthy seeds Replicate seed % loss germination

1 50 98 98 0 2 50 98 88 10 3 50 98 96 2 4 50 98 94 4 5 50 98 90 8 6 50 100 94 6 7 50 100 100 0 8 50 100 90 10 9 50 94 98 4 10 50 98 98 0 Total 500 98.2 94.6 44.00 Non-infested : Infested: X = ∑X = 98.2 Y = ∑X = 94.6 N N S²x = 3.067 S²y = 16.933 S²poold = 16.933 T-calculated = 2.55 * Reduction = 3.7% (in germination)

44

100100

% 95

% 95 HealthyHealthy seeds seeds 90 90 InfestedInfested seed seed

8585 Germinati rate Germinati rate 8080 12345678910111234567891011 CottonCotton seeds seeds FigureFigure 2: 2: Effect Effect of of bug bug feeding feeding on on the the germinationgermination rate rate of of cotton cotton seeds seeds

45 4.4 Seed Oil content

The results of the oils content analysis indicated that feeding by the bug decreased the quantity of the seeds oil. The percentage of the oil content of infested seeds was lower than that healthy seeds by 6.3% (Table 9 and

Figure 3).

4.5 Seed nitrogen content

The nitrogen content decreased due to the bug feeding. The percentage nitrogen content of infested cotton seeds was lower than that of healthy seeds by 19.5 % (Table 10 and Figure 4).

4.6 Seed Protein content

The protein content was decreased and reached to 12.5% (Table 11 and Figure 5).

46 Table 9: Effect of bug feeding on the oil content of cotton seeds

SAMPLE NO. OIL CONTENT%

Healthy seeds Infected seeds

1 25.2 23.65

2 25.05 23.43

Total 50.7 47.08

Mean± 25.13 23.54

Non-infested : Infested :

X = ∑X = 25.125 Y = ∑X = 23.54

N N

S²x = 0.01125 S²y = 0.0242

S²poold = 0.017725

Tculculated = 11.9 **

0.1331353

Reduction = 6.3 %

Note : T table = 4.303 at level 5% 9.925 at level 1%

47

2626 2525 24 24 HealthyHealthy seeds seeds

Oil conten% 23

Oil conten% 23 Infected seeds 2222 Infected seeds 1212

CottonCotton seeds seeds

FigureFigure 3: 3: Effect Effect of of bug bug feeding feeding on on the the oil oil content content of of cotton cotton seeds seeds

48

Table 10: Effect of bug feeding on the nitrogen content of cotton seeds

Sample No Content% Healthy seeds Infested seeds 1 3.570 2.87 2 3.542 2.56 Total 7.112 5.43 Mean± 3.556 2.715

Non-infested Infested

X = 3.556 Y = 2.863

S²x = 0.000392 S²y = 0.000098 Spooled =

0.000845

Tculculated = 44.28 **

Reduction =19.5 %

49

n 4 n 4

% 2 % 2 Healthy seeds

content Healthy seeds Nitrogei content Nitrogei 0 0 InfestedInfested seeds seeds 1212

CottonCotton seeds seeds

Figure 4: Effect of bug feeding on the Figure 4: Effect of bug feeding on the nitrogennitrogen content content of of cotton cotton seeds seeds

50 Table 11: Effect of bug feeding on the protein content of cotton seeds

content% Sample No % loss Healthy seeds Infested seeds 1 20.50 17.9375 2 20.40 17.8500 Total 40.90 35.7875 Mean 20.45 17.89375 2.55625

Non-infested seeds : Infested seeds:

X = ∑X = 20.45 Y = ∑X = 2.863 N

N

S²x = 0.0038 S²y = 0.005

Spooled =0.0044

T-calculated = 38.53 **

0.06633

Reduction = 12.5 %

Not : T table = 4.303 at level 5% 9.925 at level 1%

51

2222 2020 HealthyHealthy seeds seeds 18 % 18 Infested seeds % Infested seeds Protein Protein content 16 Protein Protein content 16 1212 CottonCotton seeds seeds FigureFigure 5: 5: Effect Effect of of bug bug feeding feeding on on the the proteinprotein content content of of cotton cotton seeds seeds

52

5. DISCUSSION

Little information is available in the literature about the cotton seed bug, Oxycarenus hyalinipennis Costa comprising brief notes about certain aspects of the species .The present work covered investigation on the external morphology, effect of damage on the seed weight, seed germination rate and seed contents (oil, protein, nitrogen).

As for the morphological studies, both the male and female have the similarity, except the size of body,since the female is bigger than the male

.This agreed with Kirkpatrick (1923) and Atem (1993) .During the development stages and at the beginning of the adult stage, the species has the red or orange colour and some time later it has the permanent black colour for the rest of its life. This may be considered as if they are two different species. However, this has to be looked into carefully while collecting specimens for identification.

Also during the present studies, infested seeds were lighter in weight when compared to healthy ones. As seeds were the primary diet of the bugs, all developmental stages, consumed their contents, resulting in decreasing seed weight. This agreed with the work done by Kirkpatrick (1923) in Egypt when it weight equal to 2.5 per cent of the total possible crop which reached in this work to 2.3%.

53 The studies showed that the population of the pest is very large towards the end of the season and this is reflected in the germination power

.To minimize the damage to the seeds and their germination percentage early harvesting of matured boll is to be considered. However, the average loss in infested seeds which was 3.7% came in conformity with the findings of earlier workers (Odhiambo ,1957; Sweet, 1960;, 1972; Guddoura, 1977 and

Atem, 1993).

The seeds weighed showed that the average loss in weight was found to be 2.3% . This finding did not agree with that stated by Atem (1993) whow reported that the percentage loss in average seed weight was

35.9±2.3% and 19.2±2.3% for the seasons 1990/91 and 1991/92, respectively.The differences in these results may probably due to the fact that in Atem experiment, the seeds were collected very late in the field or in other words the cotton bolls were left for longer time in the field exposing for the insect feeding, before harvest.

As for the oil content, an obvious decrease in the seed oil as a result of bug feeding amounting to an average of 6.3%. Although this agreed in the loss of oil but did not agree in the percentage of loss estimated by Guddoura

(1977) who obtained an average loss of 2.07%.

54 The present results showed the oil content percentage loss was relatively high i.e. 6.3% compared to the seed weight loss and germination percentages loss which were 2.3% and 3.7% respectively .This result is disagreed with (Atem, 1993) who reported that the effect of the infestation by the seed germination (i.e.19.22&21.4 respectively) is higher than its effect on oil content percentage loss which was 1.5 %.

The work and the losses of the protein and Nitrogen contents is first time to be carried out in the present work. However the results showed that the feeding of the Oxycarenus hyalinipennis Costa on cotton seed reduced the percentage of both the nitrogen and protein contents clearly to 12.5%, and 19.5% respectively. However ,this reduction in the percentage of both the nitrogen and protein are so light compared to the reduction the germination rate and the seed weight .Further investigation in this respect may lead to know the reason for that.

55 REFERENCES

Abul-Nasr. S.and Samy, O. (1969). Seasonal Population of Oxycarenus

hyalinipennis Costa (Hemiptera- Hetroptera) infesting cotton plant

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