454 The Grey Field Si.rcr. [Arc, 



Control. — (a) Effect of Climate. — Dry weather appears to 

 be antagonistic to slugs to a small extent only, merely driving 

 them to moist situations lower down in the soil or into the 

 depths of dense vegetation. Heavy rains, as such, apparently 

 do not affect them, except that drowning may take place in 

 pools and rnts in roadways, paths and buildings. During cold 

 weather they may go a little deeper in the soil or hide under 

 any available shelter, and become dormant. 



(h) Natural Enemies. — Tt is probable that the slug has few 

 natural enemies. Insects and fungi are only very seldom found 

 preying on them, and though in 1920 observations in Shrop- 

 shire revealed a number of dead slugs infested with maggots, 

 it is improbable that these were the cause of death. Birds 

 such as the thrush, blackbird, jackdaw and rook have been 

 observed eating slugs, and Collinge* states that slugs and 

 snails form 6.5 per cent, of the animal food of starlings.' 

 Poultry destroy numbers of slugs, ducks and geese being 

 particularly partial to them. 



(c) Combative and Preventive Measures. — As slugs readily 

 take advantage of all kinds of refuse for shelter in the daytime, 

 it would seem advisable to plough-in crop residues immediately 

 after the removal of the crop, and organic manures as soon as 

 applied. Hedge-brushings and ditch-side vegetation should be 

 destroyed: it should never be allowed to remain in heaps about 

 fields and roadsides. This is specially important during the 

 periods when no crops are available on arable land. All 

 vegetation on waste ground, hedge-, ditch- and pond-sides 

 should be periodically burned. Cleanliness and tidiness in 

 stack-yards, around root clamps, and in gardens should always 

 be maintained, since all material lying about harbours slugs 

 to a remarkable extent. 



Trapping, by means of sacks or pieces of board and bark, 

 is effective in gardens and around cold frames. Where slugs 

 are very numerous it might be advisable to apply Bordeaux 

 mixture either as a spray or in the powdered form. This has 

 given good results in America on lettuce, and in the tests 

 carried out by Messrs. Lovett and Black, "Plants sprayed with 

 Bordeaux Alixture 2-2-50 and 4-4-50, respectively, showed very 

 little indication of slug injury for a month after the time of 

 treatment." These workers also tested various stomach 

 poisons and contact irritants, but no very satisfactory or 

 practicable application was forthcoming. Copper sulphate was 



o '^The Starling-;' Jour. Min. of Agric, March, 1921. 



