365 



prevents the germination of the spores of black rot (Eavaz and 

 Gouirand). It is much inferior to cupric and mercuric salts. 



Action on Insects. — Perroncito found that a 1-5 per cent solution 

 acts better on the eggs of the mulberry bombyx than a solution of 

 corrosive sublimate of 0*5 per cent. Its energy is due to its soapy 

 nature, which surrounds the insects and their larvae and thus brings the 

 insecticide in direct contact with the vulnerable parts of the insect. 

 Insects generally succumb to a larger dose than that which is in- 

 jurious to plants ; thus the caterpillars of the cochylis touched by a 

 6 per cent solution do not die. Fleischer has summed up in the 

 following table his researches on the action of " lysol " on plant lice : — 



TABLE LXXXI. — Shoiving the Action of " Lysol " Solutions of Variotcs Strengths 

 on Plant Lice. 



This table shows that a solution of "lysol" of O'S per cent kills plant 

 lice. " Lysol " is regarded by Fleischer as the best insecticide, and by 

 Sturgis as greatly inferior to emerald green (Paris green). 



Use. — SpJuerotlieca pannosa, Wallr. (blight of the peach and the 

 rose-tree). — According to Schiller, Lambert, and Griibe, a solution of 

 "lysol" of 0"5-l per cent kills this blight. Constantin and Dufour ad- 

 vise " lysol " for the same purpose. The dose must be varied with the 

 delicacy of the rose or peach-tree. Ch. Charpentier circumscribes the 

 disease by spraying every eight days, and immediately the disease 

 appears with a solution of 3'5-4 per cent " lysol ". All the trees were 

 not radically cured by this treatment, but the disease did not increase, 

 and is not conveyed to the neighbouring sound trees. 



Peronospora viticola, De By. (mildew of the vine). — Opinions ai'e 

 much divided as to the efficiency of " lysol " against mildew. In a report 

 of the Wadenswiel Station, Switzerland, "lysol" is declared incapable 

 of overcoming this parasite. Dufour also regards it as inefficient ; it 

 gave no result ; its adherence to the leaves was also defective. " Lysol " 

 is regarded in Switzerland as inefficient and is not used. Sipiere, on 

 the other hand, advises its use in place of copper bouillies, and he has 

 praised its good effects. A "lysolage" with a solution of 0-5 per cent 

 gave him the same results as bouillie bordelaise, whilst it was also 

 cheaper. This treatment had also the advantage of overcoming oidium 



