Studies on inward leaf curl disorder in grape

摘要

Inward leaf curling/cupping is a commonly occurring disorder in Maharashtra during the grand growth period of grapes. 'Spring fever' a symptom described as a transient period of K deficiency has also been reported to occur during the rapid growth to flowering stage in Californian vineyards by Clarke (1). In the recent past, growers have shown reluctance to use potassic fertilizers due to the misconception that a fairly high level of available K content in soil ensures a ready availability of this essential element to the crop. However, a number of factors such as high Na, Ca and Mg contents in soil solution and high content of soluble salts in soil impair K availability to grapes. Potassium regulates opening and closing of stomata in leaves. Under Kdeficient conditions older leaves on vines tend to curl up (Saayman, 4) and hence shoots do not mature, yield and quality are reduced. Since leaf curl is common on Thompson Seedless grape and its clones, there has been an apprehension of virus related problem in the minds of the growers and consultants, hence the present study was carried out to find out the causes of inward curling, a K related disorder in grape.