SOME SOI 1H INDIAN INSE< rS, ETC. CHAP. XI. 



serious; occasion maj also be taken to point oul the danger 

 ■ it Hydrocyanic-acid poisoning consequent on a too liberal use 

 oi young actively-growing cereals as fodder, but it is probable 

 that this danger will be largely reduced it only plants suffering 

 from attack by inserts are used. 



Mi advantages 01 sowing crops by means of a drill and ill 

 planting out seedlings in regular lines lie. mne especially apparent 

 in the control oi crop-pests bj means such as hand-picking. If a 

 cotton-field, for instance, is planted in regular rows, it is compara- 

 tive!} eas) to go ovei the field row by row and collect cotton-bug, 

 or whatever the particulai pest is, and to be certain that no bushes 

 have been left unexamined ; but it is far more difficult to make sure 

 that no bushes have been missed out if they are planted irregularly. 

 It is also far easier to notice the first stages of an attack in drill- 

 sown crops and their intercultivation is more efficient ami makes it 

 more difficult for pests to spread. Such crops, too. are more readily 

 thinned out and the more vigorous plants which are left air bettei 

 able to withstand the attack of pests. 



Mechanical mkthods. 



Under the heading of Mechanical Methods may be grouped 

 those means of control which are intended to reduce the numbers 

 of pests, either before or after they have attained destructive pro- 

 portions, without making use of insecticidal liquids, powders or 

 gases ; but it ma\ again be remarked that it is difficult to draw 

 any definite line between mechanical ami insecticidal methods. 

 Amongst mechanical means may be included hand-picking, 

 collection b\ hand-nets or bag-nets, hopperdozers, light-traps, 

 attraction to baits and traps, trenching, burning, banding of 

 trees, screening, destruction of borers in trees, removal of dead 

 tics and branches of trees, and cutting out of deadhearts. 



The collection of insect pests by hand is an extremely simple 

 method which has also the merit of remarkable efficacy if carried 

 out regularly and on the first appearance of a pest whilst its numbers 

 are still small. If pests are allowed to increase, their numbers soon 

 become so great that hand-picking is out of the question, but in 

 the early stages of an attack a vigorous onslaught will often nip 

 the outbreak in the bud. For example, in H)I2we had a small 

 outbreak of kumblipuchi on the Central Farm at Coimbatore ; one 

 chokra was set to colled the caterpillars and in lour days had 

 collected several hundreds with the result that little damage was 

 done by that brood and no subsequent broods Were even noticed ; 



ij thi lust brood ]\.^\ not been checked, at least two subsequent 



