How to Manage Pests

Pests in Gardens and Landscapes

Fertilizing

Maintaining a good fertilization program can keep your plants vigorous and help prevent diseases such as bacterial canker and oak root fungus.

Young trees benefit from light applications of nitrogen fertilizer. Apply about 0.33 pound of ammonium sulfate (which equals 1 to 2 oz of actual nitrogen) per tree per year. Keep the fertilizer at least 18 inches or farther from the trunk and water well after application. As trees mature, increase fertilizer to up to 5 pounds of ammonium sulfate per tree per year (1 pound actual nitrogen). The ideal time of application is just after bloom.

Never use more nitrogen than necessary. Nitrogen fertilizers favor leaf growth, which may encourage insects such as aphids to build up. Be careful not to neglect other important nutrients, such as iron or potassium, or deficiencies will result.

Potassium deficiency symptoms
Potassium deficiency symptoms

Deficiency of iron
Deficiency of iron


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