How to Manage Pests

Pests in Gardens and Landscapes

Sunburn, sunscald or excessive or inadequate light

Too much or too little sunlight can damage plants. Sunburn, sunscald, and light deficiency are syndromes associated with improper light levels .
Sunburn, or leaf scorch, is damage to foliage and other herbaceous plant parts caused by a combination of too much light and heat and insufficient moisture. A yellow or brown area develops on foliage, which then dies beginning in areas between the veins. Sunscald is damage to bark caused by excessive light or heat. Sunscald-damaged bark becomes cracked, sunken, and is susceptible to attack by wood-boring insects and rot fungi. Sunscalded trunks and limbs can develop cankers, become girdled and die. Inadequate light causes pale foliage and elongated, spindly shoots. Excessive light can cause foliage to darken.

Solutions

Plant only species that are well adapted to the site where they are planted. Provide plants with proper cultural care, especially appropriate water. Prevent sunscald on the bark through proper planting and pruning. Avoid removing more than about 20% of the plant canopy in 1 year. Whitewash trunks of young trees and the older bark newly exposed to the sun. Mulches can reduce or increase heat and light around plants, depending on the location and type of material used (e.g., plastic). Avoid changing the environment in any way that significantly alters the amount of light received by established plants except purposely to remedy inappropriate light conditions.

Sunscald-damaged bark
Sunscald-damaged bark
Light damage
Light damage
Sunburned leaves
Sunburned leaves

 

 


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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