Citrus Whitefly

Encarsia and Eretmocerus parasitoid wasps specifically attack citrus whitefly nymphs -- they are already present in most outdoor citrus and provide significant suppression when not disrupted. Delphastus catalinae is a small black beetle that eats large numbers of whitefly eggs and nymphs -- preserve it by avoiding broad-spectrum treatments. The most important biological practice is avoiding insecticides that collapse these beneficial populations -- citrus whitefly rebounds far faster than its natural enemies after chemical disturbance.

Citrus whitefly populations surge on dense crowded canopies with stagnant air and excess nitrogen growth. Yellow sticky traps at canopy height monitor adult presence -- more than 10 adults per trap per week signals a building population. Avoid broad-spectrum sprays on citrus that destroy the parasitoid wasp complex that normally keeps whitefly in check. Inspect new nursery trees before planting.

Prune dense interior branches to improve airflow and spray penetration -- citrus whitefly thrives in humid stagnant canopy interiors. Remove heavily infested lower leaves on young trees to reduce population. Avoid excess nitrogen fertilization. Keep weeds near citrus mowed -- many weed species host whitefly populations that move into trees.

A strong water spray dislodges adults and nymphs from leaf undersides on small backyard trees -- repeat every 2-3 days for meaningful suppression. Yellow sticky traps at canopy height monitor and catch modest numbers of adults. For container citrus, a handheld vacuum in early morning removes significant adult populations.

Insecticidal soap with thorough coverage of leaf undersides kills nymphs on contact -- apply every 5-7 days for 3 weeks on a crawler schedule. Horticultural oil smothers eggs and nymphs. Neem oil disrupts development and reduces egg-laying. Apply all sprays at dusk to protect beneficial insects. Beauveria bassiana fungal spray infects and kills nymphs in humid conditions above 70% relative humidity.