226 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



by a slug, copious spraying with solutions of blue vitriol every fort- 

 night before transplanting have a good effect. 



Use of Blue Vitriol against Worms and Snails. — Snails and 

 slugs are as sensitive to blue vitriol as to green vitriol. If they pass 

 over a surface sprayed with blue vitriol they soon die. The hatred of 

 snails for blue vitriol is such that to remove them it suffices to stretch 

 a cord, 1^ inches wide, steeped for twenty-four hours in a 10 per 

 cent solution. This cord ought to touch the soil ; it forms an in- 

 surmountable barrier. This method is practised in Italy. Bignon 

 has also observed that the vitriolizing of ropes and trellises remove 

 slugs. 



