CHAP, XL J iin: CONTROL OF INSECT PESTS OF CROPS. 87 



(rickets, for example, often do a great deal of damage t'> crops in 



some districts. living in burrows in the ground andonly coming out 

 at night to cut off tender shoots which they carry off to their burrows 



and devour during the day-time; in such cases irrigating tin 

 affected area will drive them oul when they fall an easy prej to 

 crows, kites, and various other enemies. The manner in which 

 crows and kites will congn gate when fields are being Hooded is well 

 known to everj agriculturist and verj little observation will show 

 thai they are busj catching grasshoppers, crickets and other insects 

 winch are driven oul ol cracks in the soil by the advancing water, 

 e caterpillars, beetles, bugs and other crop-pests may also be 



mlled by irrigating the affected area, hut no general rules can 

 be laid down. Tin- addition of a bag of CrudeOil Emulsion inthc 

 irrigation channel sometimes helps to drive away certain pests, 

 temporarily at any rate. The converse of irrigation. Draining, is 

 used to control the Paddy Caseworm (Nymphula depunctalh) whose 

 larva is aquatic in habit. 



The selection ol resistant varieties of crops is a subject which has 

 hardly been touched in India but there is little doubt but that this 

 line of work offers one of the most promising lines oi research for 

 the future. It is ,1 inattei of common observation to any agricul- 

 turist that particular plants or particular varieties of plants are less 

 subject to attack b> pests than arc others grown under similar 

 conditions and by selecting and breeding from such resistant strains 

 we may hope to secure relative immunity from the ravages of pests. 

 This is not a matter in which immediate results can be expected 

 and it demands co-operation as regards the agricultural, botanical, 

 entomological and mycological aspects of the question in the case 

 ol each particular strain of each crop and perhaps the required 

 qualities may vary in different districts. In the meantime agricul- 

 turists should retain seed tor sowing from the most health) and 

 pest-resistant plants which thej can select from their fields and 

 should look on the selection ot the best seed obtainable as the vr\ 



foundation "t anj attempt t<> grow a good yield of crop. 



In some cases, especiall) in cereals where a large area is placed 

 under one crop and irrigation 01 Othei control methods ate im- 

 practicable, small patches ol a crop are sometimes found to be 

 badly attacked In a pest. In such cases it is often possible to cut 

 such patches and to U-a\ the affected plants to cattle as green fodder, 

 thus ridding the remaining area of these centres of infection and 

 at the same time making some use of the attacked plants. The use as 

 fodder of cholam, etc., attacked bj stem-borer will not hurt the cattle 

 but care must he taken not to teed hairy caterpillars (ktmblipuchis) 

 mi blister-beetles to cattle, as the effects of SUCh a diet may be 



