How to Manage Pests

Pests in Gardens and Landscapes

Frost

Frost-damaged leaves or twigs become water-soaked, wither, and turn dark brown to black. On fruit, the rind surface may appear corroded. Watery, brownish specks or pits called icemarks may be present. The pulp underneath the icemarks dries. A frost may kill young trees but rarely mature trees.

Solutions

Certain cultural practices, such as avoiding pruning or fertilizing during late summer and providing protection during critical injury times, can reduce the impact of frost. Avoid oil sprays in the fall. Protect young trees from frost damage by building a wooden framework above the tree and covering it with a cloth. Cover with a tarp in the evening when frost is expected. Remove the tarp during the day to give the tree light. Fiberglass insulation can also be tied around the trunk on a young tree to protect it from freeze damage. If trees are damaged by frost, do not remove dead leaves or twigs until late spring or summer. Prune out dead material after new growth develops. Pruning too early may remove live branches and increase the risk of more frost damage.

Frost-damaged leaves
Frost-damaged leaves

Damaged fruit
Damaged fruit (left) and healthy fruit (right)


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

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