Small Fruits 125 



begin to open; a second application should be made before 

 the first sign of the mildew, and other applications should 

 follow as need indicates. It is necessary to resulfur if from 

 one to two days at 32° to 35° C. (90° to 95° F.) or four to five 

 days at 29° to 32° C. (85° to 90° F.) do not intervene before 

 the sulfur is removed by rain. If the disease was destructive 

 the previous year, it is well to make application even earlier 

 than indicated above, i. e., when the shoots are about 15- 

 20 cm. long. 



After the grapes commence to ripen they are comparatively 

 safe from mildew, but for the future good of the vine the 

 leaves should be protected by further sulfuring if need be. 

 Young vines should similarly be protected. To properly 

 apply, use good dusting machines which give an even flow 

 of sulfur and are easy of operation. 



In climates where sulfur cannot be used to advantage 

 reliance must be placed upon Bordeaux mixture or hme- 

 sulfur applied as for the black-rot. 



.Downy-mildew ^^^' ^^-' ^"^^ (Plasmopara viticola (B. & C.) 

 Berl. & de Toni) . — Downy-mildew produces a more or 

 less distinctly visible downy or velvety growth upon the 

 affected surface, caused by myriads of spore-bearing stalks 

 that rise from the diseased surface. If these stalks are 

 close together, the appearance is thoroughly characteristic 

 and the diagnosis clear. As the spores mature the spots 

 assume a gray or frosted appearance. 



The European grapes are more susceptible to this mildew 

 than the American varieties. All the green parts of the plant 

 are affected. Upon the lower side of the leaf the disease 

 may be recognized by the description given above. The 

 upper surface of the leaf over a diseased spot becomes pale, 

 yellowish, and finally turns brown and dies. The area so 

 affected is definitely bordered and does not necessarily 

 cause the death of the whole leaf, though it may do so. 



Upon shoots the same characteristic appearance is noted 

 as upon the lower surfaces of the leaves. Sometimes the 

 death of the affected twig or even of the whole vine results; 



