Injurious Tipitlidce. 103 



PREVENTIVE AND KeMEDIAL MEASURES. 



Although there is no known remedy for " leather-jackets " in the 

 field there is much we can do to lessen the amount of harm 

 caused by them and to prevent their undue increase. In garden 

 cultivation, on the other hand, we can destroy them even in the soil, 

 if it is considered worth tlie while. 



In the tirst place, we can do some good in preventing egg laying. 

 This we may do in three ways; firstly, by keeping down all long 

 herbage during the autumn, long rank growths at the headlands and 

 along hedgerows ; secondly, by bush-harrowing pasture land or 

 heavily rolling the same when the swarms of flies are noticed in the 

 fields, hundreds will thus be killed and so prevented from laying 

 their eggs, and the eggs in many cases themselves will be destroyed ; 

 tlmxlly, late mowing and rolling of lawns, croquet grounds, etc., will 

 not only kill large numbers of the adults, but eggs as well. There 

 is no doubt that for preference the flies will go to damp areas to 

 deposit their eggs, and thus drainage will do good. This has been 

 carried out on many occasions and has always been attended with 

 good results. Pasture land and clover lay should be broken up 

 when possible early in the autumn, so that the flies can find no 

 shelter amongst which to lay rheir eggs. The land may first be 

 dressed with gas lime, spread over it at once and allowed to remain 

 on the surface for a few days. The smell would deter the flies from 

 laying their eggs and would probably affect any small larvae present. 

 The effect of gas lime is very variable, however, and it is doubtful 

 from recent experience if it has much effect upon large subterranean 

 insects. 



The old plan of " paring and burning " the stubble or grass on 

 breaking up pasture is perhaps the best method of clearing out this 

 and other ground pests. It of course has its disadvantages and is 

 now seldom practised, but there is not the least doubt that it is the 

 only way to lessen these pests in the soil. 



Eolling with a cross-kill or Cambridge ring roller does some good 

 by compressing the soil, and so preventing the " leather-jackets '' 

 from free movement in the ground. This is especially advantageous 

 where they are attacking wheat or barley. In dealing with their 

 life-history it was pointed out that the grubs come to the surface at 

 night ; a heavy ring-roller, of course, would kill any number of their 

 larvse if passed over them, and could not fail to do much good, 



