100 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



Action on Fung-i and their Spores. — Used in a dose lower than 

 0"0013 per cent coi-rosive sublimate stimulates, according to trials 

 by Ono, the growth of saprophytic fungi, but at this strength parasitic 

 fungi cannot support it. Hitchcock and Carleton found that the uredo- 

 spores of Pucclnia coronata and Pnccinia rubigo vera, which are the 

 spores of the parasitic fungi most resistant to poisonous salts, were 

 incapable of germinating in a O'OOl solution of corrosive sublimate. 

 There is, according to Wuthrich, a great similarity between the action 

 of corrosive sublimate on the spores of fungi and that of blue and 

 green vitriol. This action is, on the one hand, proportional to the 

 chemical equivalent of these salts, and on the other hand, these pro- 

 portions adhered to, corrosive sublimate is ten times stronger than blue 

 vitriol and 100 times stronger than green vitriol. The following are 

 the respective doses of these salts required to prevent the germination 

 of the different parasitic fungi : — 



TABLE LVII. — Shoiving the Dose of Green a7id of Blue Vitriol and of Cor- 

 rosive Sublimate Per Cent Required to Prevent tlie (Termination of the 

 Spores of Different Parasitic F^tngi. 



Herzberg submitted the spores of different species of Ustilago to the 

 action of corrosive sublimate and found that they all behave in much 

 the same way, with the exception of Ustilago Jenseni, which resists a 

 little better. The following are the doses which prevent the germina- 

 tion of the spores examined : — 



TABLE LVin. — Showing the Dose of Corrosive Suhlimate Per Cent Required 

 to Prev'-nt the Germination of Spores of the Various Spiccies of Ustilago. 



