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ON THE EFFECTS PRODUCED BY THE ATTACKS OF THE PINK 



BOLL WORM ON THE YIELD OF COTTON SEED AND LINT IN EGYPT. 



By Dr. L. H. Gough, Ph.D., F.E.S., 



Director of the Entomological Section, Ministry of Agriculture, Egypt. 



(Plate XVIII.) 



Summary of the Established Facts Concerning the Life-History 

 of the Pink Bollworm. 



The history of but few insects can be compared with that of Pectinophora (Gelechia) 

 gossypiella, which, having started as a minor pest in its native country and having 

 been transported by human agency to a new country, has there suddenly leapt to 

 the most important position as a major pest of the crop it attacks. In this respect 

 it may be placed with the Phylloxera and the gipsy moth. 



Although the chief object of this paper is to consider certain aspects of the damage 

 done by the pink bollworm to the cotton crop, the following short summary of the 

 established facts concerning the life-history of the insect may be useful to readers 

 not familiar with its habits. 



Food-Plants. The pink bollworm feeds on cotton (Gossypium, various species), 

 okra (Hibiscus esculentus ; Arabic : bamia ; Hindustani : bhindi), Deccan hemp 

 (Hibiscus cannabinus ; Arabic : til), hollyhock (Althaea rosea), mallow (Malva sp., 

 probably silvestris), Thespesia fopulnea (fide Fullaway ; this record is considered 

 doubtful by Busck), and Abutilon sp. (Arabic : hanbuJe ; fide King). 



It will be noticed that all these plants belong to the Malvaceae. The record for 

 pomegranates given by Dudgeon and Gough is without doubt due to error. 



Of all these food-plants cotton is preferred. The larvae attack the stems (feeding 

 in the cambium and boring a tunnel which encircles the stem), flowers, flower-buds, 

 bolls and seeds. The order of preference is the inverse of that given above ; stems 

 are very rarely attacked, maturing seeds are the favourite food. Attacked buds 

 almost invariably fail to mature into flowers. Bolls attacked during the first weeks 

 of their development are entirely eaten out, or dry up and fall. 



The pink bollworm is now known to occur in India, Palestine, Mesopotamia, 

 Ceylon, Burma, Straits Settlements, China, Japan, the Philippine and Hawaiian 

 Islands, East Africa, Zanzibar, Egypt, Sudan, West Africa (S. Nigeria, Sierra Leone), 

 Brazil, Mexico, and Texas in the United States. Palestine and Mesopotamia 

 constitute new locality records, seed showing typical damage having been received 

 by us from both places. 



The eggs are minute and are laid singly, or in small groups up to ten. They 

 are to be found on the bolls, involucres, leaves and axils of leaves. The egg-stage 

 in Egypt is known to last from 3 to 7 days. Busck gives the period as 4 to 12 days. 

 Owing to the small size of the eggs, the insect cannot be controlled at this stage. 



