THE GRAPES OF NEW YORK. 87 



nose/ or " bird's-eye rot " and chlorosis,^ or " yellow-leaf ". Vineyards 

 are very generally sprayed in this district and usually with satisfactory 

 results. Grape-growers have learned that certain varieties are much more 

 susceptible to some of the diseases than others and plant accordingly. 



on the upper surfaces of the leaves and give the leaf a gray, powdery appearance — hence the name, 

 powdery mildew. Affected leaves finally become light brown and often fall. Diseased fruits are 

 gray in color, scurfy, become specked with brown, fail to develop and often burst on one side thereby 

 showing the seeds. The winter or resting spores are borne in sacs, in the latter part of the season. 

 The spore sacs, in their turn, are borne in small, black, spherical spore cases, each furnished with a 

 number of slender appendages having curled tips. The powdery mildew, unlike most other fungus 

 troubles of the grape, is most prevalent in hot dry weather. The disease is combatted by dusting 

 with flowers of sulphur or by spraying with bordeaux mixture as for black-rot. 



■ Anthracnose (Sphaccloma ampclitinm De By.). — This disease attacks any of the tender portions 

 of the growing vine. When the leaves are affected dark spots are first formed on their surface. As 

 the disease advances these spots enlarge, and irregular cracks are often formed through the dead 

 tissue. Frequently many of these small cracks run together, forming a long irregular slit through 

 the leaf. Similar marks are formed on the tender shoots, though they are not so noticeable. When 

 the fruit is attacked the disease is sometimes called bird's-eye rot. Circular spots are formed on the 

 surface of the berry. The spots may be of different colors and usually have a dark border; as the 

 spots enlarge and eat in, a seed is often exposed in the center. In rotting the tissue becomes hard 

 and wrinkled. Sometimes the disease girdles the stem of a fruit cluster, cutting off the supply of 

 sap from the grapes beyond the diseased line and causing them to shrivel and die. 



Anthracnose does not spread as rapidly as some other vineyard diseases, neither does it yield 

 as readily to treatment. When a vineyard is badly infested with anthracnose, it requires prompt 

 attention and a careful treatment to control the disease. It is not satisfactorily controlled by bor- 

 deaux mixture alone. It is suggested that in addition to such treatment with this mixture as is 

 given for black-rot the plan be followed which is advocated by certain European authorities, of 

 applying a warm saturated solution of copperas (iron sulphate) in spring when the buds are swelling 

 but before they begin to open. One per ct. or more of sulphuric acid may be added to the solution 

 before it is applied. This solution must be handled with care as it is very caustic. It is applied 

 with swabs or if the acid is not used it may be sprayed. It is essential that the work be done thor- 

 oughly, covering all the surface of the canes. 



- Chlorosis or yellow leaf. — The name is applied to a grape disease in which the foliage turns 

 yellow, later becoming brown. It is common in several parts of the State but more particularly in 

 the Central Lakes district. Chlorosis is more likely to appear in wet seasons. Some varieties, as 

 the Diamond, are much more susceptible than others. In some seasons portions of the leaves may 

 become yellow but eventually 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 



