Tree vigor is diminished by feeding activities and inhibition of photosynthesis by sooty mold growing on the leaves. Citrus mealybug is controlled most effectively with pesticides during early stages before protective wax secretions and sooty mold form. Monitoring activities must be concerned with identification and quantitative assessment of first and second stage larvae. Mature mealybugs are highly resistant to contact pesticides. Heavy infestations interfere with fruit development and may cause fruit drop.
Sooty mold is difficult to remove at the packing shed, often resulting in downgrading of fruit.
Mealybugs have several predatory and parasitic natural enemies. Severe outbreaks in orchards not normally affected by mealybugs usually are the result of pesticide-related reductions or other unfavorable circumstances affecting natural enemies. Texas leafcutting ants can cause serious damage to citrus, particularly In young plantings, so monitoring notes on location and severity of infestations will facilitate control efforts. The leafcutting ant poses a special problem in well-drained sandy loam soils because it may nest some distance from the orchards Repeated defoliation of trees reduces tree vigor, eventually killing young trees. Locate the nest by tracking at dawn or dusk or during periods of cloudy weather because aboveground activity ceases during direct sunlight.