Adhesive Properties of Fungicides. 47 



the first to use the remedies (see page 29) on other plants, and 

 some experimenters soon followed their example. Aime Girard 1 

 in 1888 and 1889 made some very conclusive experiments upon 

 the potato. Among the points emphasized by him may be 

 mentioned the fact that curative applications do not assure 

 complete immunity ; he also noticed that there was a great 

 difference in the varieties as regards their susceptibility to the 

 disease. 



Chatrin applied the Bordeaux mixture to pears in 1890 2 for 

 a disease commonly known as " tavelure." It is caused by a 

 fungus, Fusicladium pyrinum, and his applications are said to 

 have been followed by good results. Another fungous disease 

 commonly known as " cloque," probably due to some species of 

 Taphrina or Exoascus, was receiving attention. 8 The trouble 

 is mentioned as affecting peach trees. It causes the leaves to 

 curl in a manner similar to that which is only too frequently 

 seen in America. Lesne advised growers to spray their trees 

 with the Bordeaux mixture, but this recommendation does not 

 appear to have been founded upon successful work. 



Aime Girard 4 conducted some experiments to test upon 

 potato foliage the adhesive powers of various fungicides. His 

 conclusions are as follows : 



" 1. Copper compounds adhere to foliage with different de- 

 grees of persistence. 



" 2. Under the action of severe rains, copper disappears 

 largely on account of the mechanical action of the water. 



" 3. Among these compositions the one which washes the most 

 is the Bordeaux mixture of various formulas. The diminution 

 of the proportion of lime augments a little the adhesive power ; 

 but the addition of aluminous materials does not produce any 

 sensible amelioration. 



"4. The precipitated carbonate of copper (bouillie cupro- 

 sodique) on the one hand, and verdet on the other, have the 

 faculty of adhering almost twice as w r ell as the Bordeaux mix- 

 ture. But above all others Ferret's mixture of copper, lime, 

 and sugar [see page 43] resists the action of rains remarkably 

 well. Therefore the last is to be preferred, other things being 

 equal, and its use is advised." 



1 Jour. d'Ag. Prat. 1890, June 5, 803. Ibid. 1891, May 21, 736. 



* Ibid. Nov. 20, 755. * Ibid. 1892, Feb. 4, 177. 



