416 rnocEBDiNGS of the thibd entomological meetino 



For entomological observation the following plants were grown in 

 ^ acre plots side by side : 



Maize Juar. Bnjra. Sudan Guinea Rarhi Batri 



(Impey grass grass 



variety). 



At a distance of about 200 yards from this variety plot there was 

 in the trenching ground about 2 acres of winter paddy, there being 

 no other rice within about half a mile. All of the above remained on 

 the ground fi-om about June to November. Rarhi and hatri did not 

 have good growth as they require well-developed roots which cannot 

 grow unless they be at a place for a few years continuously. 



In i]xQJuar, Chilo simplex occurred in large numbers, Diatrcea venosata 

 in smaller numbers and Sesamia inferens in still smaller numbers. 

 Between 11th and 16th October, out of 3,174 plants in the entire plot, 

 501 were observed to have been bored in the stem and each stem to 

 harbour from 3 to 8 larva3 and pupae of Chilo simplex. The affected 

 plants were cut and kept under observation. The caterpillars hibernated 

 in them. 



In Sudan grass, Chilo simplex and Diatrcea venosata occurred to the 

 same extent as mjuar. 



In maize, Chilo simplex and Sesamia inferens, the latter in smaller 

 numbers, occurred up to about August. In the ripening plants there 

 was hardly any borer. 



In bajra there was no borer. Only one Chilo simplex larva was 

 observed in the entire plot. This crop is usually observed to be practi- 

 cally immune. 



In Guinea grass there was no borer. 



In rarhi, Diatrcea auricilia occurred in small numbers. 



In batri, Diatrcea auricilia and the Zeuzerid borer (C. S. 1696) occurred 

 in small numbers. 



In the neighbouring rice plot hardly any Chilo simplex occurred al- 

 though it was occurring in numbers on rice outside the Pusa Estate. 



Parasites and Predators. 



Special attention has not been paid to parasites of the borers but 

 parasites necessarily came under observation in the course of examining 

 ■ thousands of caterpillars and pupae. At Pusa, Dacca and Cawnpore and 

 probably in the whole of North India there are hymenopterous para- 

 sites including Chalcidids, Braconids and Ichneumons on practically 



