432 Report oF THE HORTICULTURIST OF THE 
Chlorosis is more likely to appear in wet seasons. Some varie- 
ties, as the Diamond, are much more susceptible than others. In 
some seasons portions of the leaves may become yellow, but event- 
ually regain their normal color so that at the close of the season 
the vine appears to be in a healthy condition. In other instances 
the yellow color extends over the entire leaf; brown, dead patches 
appear; the leaf curls and eventually drops from the vine. If the 
vine loses its leaves two or three seasons in succession it is likely 
to die. One striking peculiarity of the disease is the fact that a 
badly diseased vine may appear by the side of a perfectly healthy 
vine of the same variety. 
The cause of chlorosis, as given by foreign investigators, is the 
presence of a large amount of lime in the soil which prevents the 
roots from taking up an amount of iron sufficient for satisfactory 
growth. Their experiments show that the difficulty may be over- 
come by applying a small amount of sulphate of iron around 
affected plants. But since there are a number of good American 
varieties that are not subject to chlorosis, perhaps the better 
method to pursue is to plant only such varieties as are known to 
be free from this trouble. 
The standard varieties given in the following list are, so far as 
we know, practically exempt from chlorosis: 
Moore Early, Concord, 
Winchell, Catawba, 
Delaware, Vergennes, 
Worden, Agawam. 
Niagara, 
DOWNY MILDEW. 
(Plasmopara viticola (B. & C.) Berl. & DeT.) 
Description.— In some sections of the State the downy mildew 
causes considerable loss to the grape grower. It may attack 
nearly every portion of the current season’s growth,— leaves, 
shoots and fruit. Its first appearance on the leaves, that will be 
