I II j It r ions 'ripiiliihc. 103 



riJKVENTIVK AND UkMKDIAL MkASL-KES. 



Ahliough lliei-e is uo known it'int'dy I'di- " leallier-jackcts " in tin- 

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

 caused I'V ihem and to prevent their undue increiu^e. In j^arden 

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

 if it is considered wt>rih the while. 



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

 This we may do in tiiree ways ; fii-stly, hy keeping down all long 

 lierhage during the autumn, long rank gr«»wths at the headlands and 

 along hedgerows ; secondly, by bush-haiTowing jjasture land or 

 heavilv rollin<' the .same when the swanns of tlies are notice<l in the 

 fields, iuindreds will thus 1)0 killed and so pi-eventetl from laying 

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

 thirdly, late mowing and rolling of la^\'ns, 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 ai-eas to 

 dep<^>sit their eggs, and thus drainage will do good. This has been 

 canied out on many occasions and lias always been attendetl with 

 good results. Pasture land and clover lay should l)e broken up 

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

 shelter amongst which t<i lay iheir eggs. The land may first be 

 dres.sed 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 tlieir eggs and would probably all'ect any small larva^ present. 

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

 from recent exj>erieuce if it has much etlect ujxm largo subteminean 

 insects. 



The old jtlan of "paring and burning" tiie stubble or gn».«*s on 

 breaking up j)asiure is jMirlmps the Injst method of clearing out this 

 and other ground jHJSts. It of course has its di.sadvantages and is 

 now sehlom practise<l, but there is not tin' least tloubt that it is the 

 only way to les.sen the.se i>ests in the soil. 



Kolling with a cn>ss-kill or Cambridge ring roller does some goo<l 

 by comprossing the soil, and so preventing the " leather-jackets " 

 from free movement in the ground. This is es|xM'ially advantageou.s 

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

 life-histor}* it was pointed out that the grubs come to tlio surface at 

 night ; a heavy riug-rt»ller, f»f ctair.se, would kill any numljer of their 

 larvflc if passed over them, antl could not fail to do much g<Kxl, 



