474 mocEEDixGS of the third entomological meeting 



The original home of the Piuk Bollworm appears to be most pro- 

 bably Asia. The insect was probably introduced from India into 

 (German) East Africa before the German occupation ; according to 

 the accounts by various German authors, the insect is thoroughly 

 established there. Trade with East Africa before the advent of the 

 Germans was practically all with India. Its spread to Zanzibar is 

 understandable in view of the trade connections with India. 



Although the introduction of the Pink Bollworm took place so 

 recently, very little is really known about its rate of spread in Egypt. 

 A few records are given by Willcocks, for the locahties in which it was 

 noted before 1913, but these records are defective in many ways, especi- 

 ally as they are the result of stray notes and not of an organized search 

 for the insect. Although first recorded in Egypt in 1910 from around 

 Alexandria we have distinct evidence in the shape of hollowed-out 

 seeds, ginned at Maghagha in Upper Egypt in 1911, that it had already 

 reached so far in the first year after its discovery. 



Food-Plants. The principal food-plant is without doubt cotton ; 

 it feeds on various other malvaceous plants contrary to the assertion 

 of Busck which has apparently been accepted by the American authorities. 



On cotton the larva feeds in the seeds, bolls, flower-buds, flowers 

 and in the stem, in which last it bores in the cambium ; the order of 

 preference bemg as stated. 



It was found in an experiment made at the Government farm at 

 Gemmeiza in 1917, that during the 19 weeks from June 9th to October 

 20th, of 44,013 buds only 165, of 5,792 flowers only 13 and of 48,395 

 green bolls 16,831 contained worms or showed signs of previous attack 

 or both (Plate 80). Of the green bolls very many certainly contained 

 more than one larva. This represents the total number of buds, flowers 

 and green bolls found on 9,300 plants ; 100 plants being daily pulled up 

 and examined until the 15th September, after which only 50 plants 

 were utilized for the daily counts. Recalculated in such a way that 

 each week is made to weigh in its proper proportion and calculating 

 all the buds, flowers and bolls each as 1.0,000, the proportion of attacked 

 flowers is found as 42 in 10,000, buds 67 in 10,000 and bolls (green) 

 4,346 out of 10,000. (See Table II.) We will have to come back to 

 this subject later on. 



After cotton the chief host plant in Eg}^t is the Okroe (Hibiscus 

 esculentus). (See Table III.) And here it may be mentioned that we 

 totally disagree on this subject with the views of Busck, who denies that 

 the Pink Bollworm feeds, or develops through, on any other plant than 

 cotton. Our experience has shown us that at certain seasons, it can in- 

 fest oJcroe pods to a serious extent (16 per cent.). (See Table IV.) 



