1074 PROCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 



of the eutomologist capacity to iiiulerstaud aud to carry out the recom- 

 mendations. 



Measures of control and prevention against insects may be broadly 

 placed under two categories. In one, definite results can be expected 

 by the adoption of certain definite measures. If the Scales, Mealy- 

 bugs aud Alem'odids, etc., are sprayed with certain spray-fluids, we 

 can see the results at once. The insects are killed and the plants saved. 

 Great progress has been made in this respect in America and other 

 countries. Although similar results can be expected and are obtained 

 in India, a good deal of work has yet to be done to test the fumigants 

 and sprays under Indian conditions of temperature and moisture and 

 especially to find out simple things which the Indian cultivator can 

 make up and use with small expenses within his means. In the other 

 category such definite results can hardly be expected and mider it are 

 included the majority of the pests, caterpillars, grubs, bugs and the 

 whole host of insects affecting garden, vegetable and field crops. In 

 their case, the measures of control and prevention, however carefully 

 and accurately they may have been worked out, can only approximate 

 to certainty in their results. With regard to most of these, although 

 the Agricultural Department with a recognized entomological staff has- 

 now been in existence in India for about a decade and a half, Economic 

 Entomology may be said to be still in its infancy. It has not yet been 

 possible to make out a complete survey of the pests, although most of 

 the prhicipal ones have been discovered. Of the known ones again, 

 on account of the paucity of workers, it has not been possible to carry 

 out the intensive study necessary to understand them in all their aspects, 

 viz., in relation to the agricultural practices followed for cultivating 

 the crop or crops concerned, the climate, presence and absence of alter- 

 native foodplants and various other conditions, a correct study of which 

 is necessary to grasp their real nature. Insects like all other living 

 creatures are influenced by varying conditions of early or late rainfall, 

 drought, scarcity or abundance of food and presence or absence of 

 enemies. Therefore, unless we are able to keep) them under careful 

 observation for a series of years our knowledge of their real behaviour 

 is extremely defective. It has not yet been possible to devote such 

 study to them and in fact no attempts at th" study of most of them have 

 yet been made. Our recommendations to combat them are therefore in 

 most cases based on general observations and deductive inferences. 

 For instance, borers in sugarcane cause " dead heart." On the principle 

 of " catch and kill," to diminish the number of borers, recommendations 

 have been made to cut out the shoots with " dead heart." Similar 

 measures are recommended for borers in rice which cause dry ear. 



