mOCEEDINGS OP THE THIRD ENTOMOLOGICAL MEETING 545 



the temperature conditions in the soil will be quite difierent to what 

 they are in the laboratory, and the same applies to the humidity 

 oonditions. 



" The main object of this experiment was really to give us positive 

 evidence of the survival of the Pink Bollworms in bolls buried to a 

 depth of 5-10 cm. to a date after the restrictions on the irrigation of 

 sMraki lands [land which has grown crops of bersim, beans, wheat or 

 barley, and has been left fallow, after the cotton crop] are removed ; 

 this happens as a rule about the end of June. We obtained our 

 evidence, since at the end of July there were still live Pink Bollworms 

 present at 5 and 10 cm. depth. Other experiments at this time, and 

 others made in 1916 and 1918, confirmed this. 



" I am thus still of the opinion that we have in these Pink Boll- 

 worm infested buried bolls a source from which the growing cotton 

 crop might be infested. But as to its relative importance in this connec- 

 tion I do not feel in a position to say anything definite — all I can say 

 -at present is that the number of fallen bolls left on the ground after a 

 cotton crop, and which will be turned in by ploughing, etc., may be 

 very large, and furthermore the Pink Bollworm population in these 

 bolls may be very large also— it varies of course, but might be anything 

 from 10,000 to 100,000. Thus, given only a very small percentage 

 of survivals to the end of June, when conditions— owing to the watering 

 of the dry soil— I mean the shiraki lands — will be much more favourable 

 to the Pink Bollworm, there might be sufficient moths produced from 

 this source to be of considerable importance, as these would find condi- 

 tions in the cotton fields very favourable to their rapid multiplication. 



" I may point out here that the Ministry of Agriculture do all they 

 can to make farmers collect fallen bolls before ploughing for the following 

 crop. 



" You will see by the results given in the Table that the survival 

 of Pink Bollworms was greatest under wheat and bare fallow and least 

 under bersim. 



" The bolls buried under wheat crop gave us the highest figure for 

 survival of Pink Bollworms, but I do not know if the difference over the 

 figure in the bare fallow pits is sufficient to signify anything. 



" I attach great importance to the influence of moisture, when the 

 temperature is high or fairly so, on the activity of the Pink Bollworm, 

 •especially in inducing the larvae to leave the bolls or seeds and pupate. 

 It is possible that the soil under a crop receiving only a very moderate 

 amount of water would be drier than soil bearing no crop, owing to 

 the large amount of water taken and evaporated from the plants. 

 However, in' this case I canno' say that the wheat pit bolls were drier 



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