44 



2 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



and Mr. C. C. Ghosh, read at the Third Entomological 

 Meeting, and which is still in the press. Since then con- 

 siderable further information has been collected and brief 

 notes on the more important points only can be given here ; 

 it is intended to write up these further results more fully 

 in a separate paper. 



As ascertained by observations extending over the last 

 four years at Pusa, the principal damage to the sugarcane 

 crop occurs in the early stages of its growth in April, May 

 and June, when the climatic conditions at Pusa are charac- 

 terized by high temperature, very low humidity (at least 

 for the earlier portion of this period) and scantiness or 

 absence of rainfall. The incidence of attack by insect pests 

 is apparently correlated with climatic conditions. Favour- 

 able climatic conditions, enabling the crop to grow rapidly, 

 have a great effect in controlling the activities of the pests, 

 the crop in such cases easily outgrowing their attack. But 

 with unfavourable climatic conditions, especially drought 

 and want of moisture in the soil (and it must be remember- 

 ed that sugarcane is not grown as an irrigated crop in these 

 parts), the insects get the upper hand and owing to want of 

 growth and tillering on the part of the plants the loss 

 caused by their attack is not compensated for, the result 

 being that the percentage of damage becomes very high. 

 In 1920 the sugarcane was planted as usual about the middle 

 of February but, in contrast to previous years, this was done 

 after irrigating the land in order to secure proper moisture. 

 No further irrigation was ' done and there was no rain 

 worth mentioning until the middle of June. In April the 

 damage in some of the thick canes at Pusa was as high as 

 ten per cent., whilst at Coimbatore and Hebbal (Mysore) 

 similar canes, although planted about the same time as but 

 far more advanced in growth than the canes at Pusa, hardly 

 exhibited any damage except a few occasional dead-hearts 

 here and there. The sugarcanes at Manjri, planted earlier 

 and grown under irrigation, were certainly not as good as 

 the Coimbatore and Hebbal canes either in growth or as re- 

 gards infestation by borers. The damage about this time 



