68 



growing season, of four to five weeks each. A small proportion of 

 the larvae, however, spin a particularly tough cocoon within the 

 seed in which they have been feeding or within a double seed, and enter 

 into a resting stage in which they may remain during two winters 

 and the intervening summer, and perhaps much longer. There is 

 apparently no difference between the short-cycle larvae and those 

 that will enter the resting stage, and it is not known what factors 

 give rise to this condition ; temperature and moisture do not seem 

 to determine it. It is during the resting period that remedial measures 

 can be most easily appUed. 



The nature of the damage caused by P. gossypiella and its effect 

 upon the yield of cotton is discussed [E.A.E., A, vii, 489]. The 

 first infestation of the season results from the moths developing 

 from larvae that have passed the winter in the resting stage, and the 

 attack generally begins in May or early June, and increases rapidly 

 throughout the season. 



Various opinions are quoted regarding the attraction of the moths 

 to light. It has been the author's experience that the pink bollworm 

 is attracted to lights in Egypt, both in the field and in storage. The 

 moths are evidently crepuscular, their activities being greatest shortly 

 after sunset. Experiments in the insectary indicate that they probably 

 do not come to light on the first night of their adult existence, but 

 that their impulse on emerging is to make for the open field. The 

 relative abundance of E. insulana and P. gossypiella in recent years 

 is discussed \loc. cit.']. 



Several natural enemies of P. gossypiella exist, but either through 

 lack of numbers or owing to the time of their occurrence they exercise 

 very little control. The most important of these is Pediculoides 

 ventricosus. This mite attacks and destroys large numbers, but its 

 attacks come very late in the season. Moreover it also attacks 

 human beings, producing great irritation of the skin. Several 

 Hymenopterous parasites also occur, but are inefficient checks. It 

 is only late in the season when there are many open bolls exposing 

 the bollworms that the parasites have much opportunity of attack. 

 It is hoped that an egg-parasite may be discovered. 



The most important consideration in attempting to exterminate 

 the pink bollworm in Egypt is the destruction of the larvae at the 

 end of the season, both those left in bolls in the field and those 

 removed with the crop. It is essential that all infested material left 

 in the field should be collected and disposed of, and this is provided 

 for by law. The cotton sticks are all inspected before being taken 

 into the villages and any old cotton left on them is carefully cleaned 

 off. Various methods of cleaning the sticks are described. A 

 machine for this purpose has been devised and is very promising ; 

 moreover it provides for conserving all the waste materials removed 

 from the sticks, which can be used as fuel. 



The most successful treatment for infested cotton seed is found 

 to be heat [R.A.E., A, vi, 42]. Seed cotton or cotton seed may be 

 stored in Egypt only in licensed warehouses, the doors and windows 

 of which are protected so as to prevent the emergence of moths that 

 develop from larvae in the seeds. Early ripening varieties of cotton 

 are a great advantage in minimising pink bollworm attacks. Early 

 ripening can to a certain extent be induced by withholding irrigation 



