How to Manage Pests

Pests in Gardens and Landscapes

Leaf scorch

Leaf scorch causes leaves to become brown around the edges and sometimes between the veins. Leaf scorch is caused by a variety of environmental factors and salt burn or mineral toxicity that restrict the movement of water to the leaves. Dry, brown, dead leaf margins are often caused by twohorned oak gall wasps, Dryocosmus dubiosus, infesting leaf undersides. Portions of the leaf die back beyond where tiny galls occur on the underside of leaves, usually along a vein. Mature galls may drop, leaving only dead leaf margins with no obvious cause. Twohorned oak gall wasps pupating in litter and soil under trees are attacked by parasites and fungi. Groundcover, irrigation, and rainfall apparently affect the abundance of this gall wasp and its natural enemies. The gall apparently does not harm the oaks, populations vary naturally from year to year


No control is recommended. Keep plants irrigated deeply and thoroughly.

Leaf scorch
Leaf scorch

Galls caused by twohorned
Galls caused by twohorned oak gall wasp

Statewide IPM Program, Agriculture and Natural Resources, University of California
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