How to Manage Pests

Pests in Gardens and Landscapes

Water excess or deficiency

Improper irrigation is probably the most common cause of plant damage. Inadequate water amount causes foliage to wilt, discolor, and drop prematurely. Overwatering is a more common problem than underwatering. Overwatering problems occur primarily because water is applied too frequently rather than too much being applied during a single irrigation. Overwatering is especially damaging when drainage is poor. Excess moisture kills roots. As roots die, foliage discolors and dies. An inappropriate amount or frequency of irrigation predisposes plants to attack by mites and certain insects. Most pathogenic bacteria and fungi require moisture to infect plants and cause damage; good water management is critical to effective pathogen control.


Plant in well-drained soil and at the proper depth. Monitor plants and environmental conditions to determine irrigation need and frequency. Avoid overwatering by irrigating less frequently. Consider switching from overhead irrigation to drip irrigation to minimize water and also decrease humidity and foliar diseases.

Browning of Kalanchoe caused by drought Browning of kalanchoe caused by drought

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