Once insecticides targeting thrips kill these parasitoids, groves containing low numbers of citrus mealybugs quickly become heavily infested. Citrus mealybugs cause direct and indirect damage. Heavy infestation on the fruit can cause the fruit to drop from the tree. Indirect damage is caused by unsightly contamination of the fruit from the mealybugs themselves and from honeydew excretions and sooty mold. Heavy infestations of citrus mealybug are very difficult to chemically control.
Mealybugs prefer to infest the fruit and cover themselves with a dense waxy material.
It is difficult for insecticides to penetrate the waxy covering and mealybugs on the backside of a piece of fruit or in the inner tree canopy are difficult to cover. The woolly whitefly causes damage similar to the citrus mealybug except it does not infest the fruit. Not much is known about the woolly whitefly in Arizona. It was found in the State in 1996, and currently infests only one commercial lemon grove. Like the citrus mealybug, it produces a protective waxy covering and is difficult to control with insecticides.