144 COLEOPTEEA OR BEETLES. 



to be exempt from their attack. They feed very ravenously, 

 and destroy far more than they can devour, hence the great 

 damage caused by them. Permanent pasture and clover ley 

 contain the greatest number of these pests, as they can there 

 work without being molested. Serious attacks of this larva 

 usually follow the breaking-up of pasture and clover leys, unleSs 

 the land is to some extent freed of these vermin first. 



Prevention and Remedies. — "When land is going to be broken 

 up, it is well to feed it down with sheep, and then feed 

 them artificially on it. By so doing all the available herbage 

 is cleared off, the land is trodden down firm, preventing the 

 wireworm from moving and made objectionable by virtue of 

 the sheep excrement. This process places the pests under un- 

 favourable conditions. On breaking the land up a dressing of 

 gas-lime is most beneficial, if applied in a proper manner, and 

 perhaps forms the only successful insecticide for wireworm. 

 Mustard will never be touched by these elater larvse, and thus 

 may be advantageously employed as a green manure. It should 

 be let grow to about a foot high, and then either ploughed in 

 direct or partly fed off by sheep, and then turned in : excellent 

 results follow this method. As wireworm move about in the 

 soil from plant to plant, frequent and heavy rollings with a 

 Cambridge ring-roller cannot fail to have good effects ; in attacks 

 upon wheat and barley this is the best remedy, followed by a 

 good dressing of artificial manure to force on growth and repair 

 the damage. The destruction of all weed growths, particularly 

 couch grass, is highly necessary ; wireworm are always most 

 destructive on badly farmed and unclean land. I know of no 

 manures, unless it be seaweed, deleterious to them. Mustard 

 dross has been said to have good results in driving them away, 

 but experiments in the laboratory and on the farm do not 

 bear out this statement. In garden cultivation the use of bi- 

 sulphide of carbon and trapping may be resorted to with good 

 effects. The value of the rook and other birds is considered in 

 a later chapter. 



