INSTITUTE, PUSA, FOR 1919-20 69 



the maximum shade temperature reaching as high as 

 112-3°F. The ground soon lost moisture and as a result 

 the plants did not boll well; indeed, in the case of some 

 varieties of cotton, there were no bolls at all to continue 

 the countings. Sylepta derogata, together with Phena- 

 coccus hirsutus and Ph. corymbatus, appeared and did con- 

 siderable damage to certain varieties of cotton. During 

 the year Hibiscus abelmoschus continued to be a better trap- 

 crop for Cotton Bollworms (E 'arias) than either bhindi 

 (Hibiscus esculentus) or hollyhock, and as in previous years 

 a larger number of bollworms and of Microbracon lefroyi 

 were found in the pods of H. abelmoschus. A survey of 

 alternative f oodplants of bollworms was made and is being 

 continued. Microbracon lefroyi continued to be the most 

 prominent parasite of Earias. 



Rice. Work on the borer pests of rice has been con- 

 tinued in the neighbourhood of Pusa and confirmed the con- 

 clusion arrived at in last year's Report that on the average 

 in the Pusa district these borers cause a relatively small 

 amount of damage, amounting to about 4 per cent. In order 

 to get an idea of their activities in some of the other rice- 

 growing districts in Bengal and Bihar, the rice-stubblen of 

 the following places were examined in December 1919. 



At Chinsurah, stubbles examined in and around the 

 Farm showed about 13-5 per cent, damage by borers. The 

 actual damage to the crop (for reasons explained in the 

 preliminary paper on Borers) would be less than this. In 

 about 800 stubbles examined the following insects (larva, 

 pupa or empty pupa-case) were obtained : — 



Schosnobius bipunctifer . . . -5 



Chilo simplex . . • . .1 



Chilo oryzce ...... 1 



At Midnapur, stubbles collected from the neighbourhood 

 of the town showed about 54 per cent, damage by borers. 

 From about 500 stubbles examined the following insects 

 were obtained : — 



Schoenobius bipunctifer . • * 



Chilo simplex .-..•••■*• 



