00 REPORT OF THE AGRICULTURAL RESEARCH INSTITUTE 



but it is not possible, in a brief report of this nature, to 

 mention, even by name, all the insects dealt with during the 

 year : — 



1. Cotton. Experiments, commenced last year, were 

 continued to test the relative immunity to bollworm attack 

 of different varieties of cotton from the United Provinces, 

 the Punjab, Bombay, the Central Provinces, and Madras. 

 With this object in view, two sowings of each variety were 

 made, one planted thickly and the other thinly, and weekly 

 counts of affected bolls have been made separately for each 

 series. The parasites that emerged were counted, recorded, 

 and liberated; their hibernation and alternative hosts "were 

 also studied. One unexpected discovery was that there are 

 apparently at least five different species of RJwgas which 

 attack cotton bollworms (Earias fabia and E. insulana); 

 their discrimination may prove to be of practical import- 

 ance in control of bollworm by means of its parasites. The 

 life-history of Earias fabia was worked out and repeated; it 

 will be repeated again for the different seasons of the year. 

 The seasonal colour variation of bollworm moths was also 

 studied and a long series of specimens retained showing 

 range of variation. Studies were also made of the utility 

 of trap crops in connection with control of bollworm. The 

 advantage of sowing cotton as a mixed crop was also 

 studied and these experiments will be continued and the 

 results written up as requisite. 



At the end of May 1915, the Director of Agriculture, 

 Punjab, requested the despatch to Hansi of bollworm 

 parasites in order to establish a breeding plot and so faci- 

 litate their distribution in the Punjab. Between 7th June 

 and 22nd July 1915, 158 grubs and pupae of RJwgas spp. 

 were despatched from Pusa to Hansi, and after the latter 

 date sendings were discontinued as the parasites were fully 

 established in the experimental plots at Hansi. 



2. Rice. A diseased condition of growing rice plants, 

 by which the whole growing stem is converted into a long, 



white, hollow gall, has long been supposed to be due to 



