LEAF SILVERING OF Cucurbita

Abstract

Leaf silvering is an important physiological disorder of summer squash (Cucurbita pepo) grown in Israel. The symptom, in mild cases, is a silvering parallel to the veins in the upper surface of leaves, but in severe cases silvering includes the entire upper leaf surface and the bleaching of stems, petioles, flowers and fruits. Leaf silvering was distinguished from silver mottling, a genetically controlled characteristic, by differences in distribution of silver over the leaf surface, the developmental reversibility of silvering and the bleaching effect of severe silvering on various plant parts. Low soil moisture increased the severity of silvering.Key words: Squash (summer), marrow, Cucurbita pepo, Cucurbita moschata, physiological disorder, stress (drought, water).