So far, it looks like the biological control agents are winning. The battle is crucial, as the citrus blackfly is considered to be the most injurious insect affecting citrus trees and can rapidly cause a tree to stop bearing fruit. The adults can fly, but the juveniles appear as tiny black scales attached to the undersides of the leaves.
Whiteflies injure plants by sucking out the sap and nutrients.
Feeding by large numbers of adult and juvenile whiteflies weaken trees and may dramatically reduce or prevent fruiting. The citrus blackfly was first found on Oahu in July 1996, and a month later on Maui and the Big Island. The first identification of the pest on Kauai, was reported a few months ago by a University of Hawaii county agent. Soon after its discovery in Hawaii, the HDOA's Biological Control Program began surveying the state for pest infestations and plans began for exploration to search for biological control agents to attack this menacing whitefly. Several possible biological control agents were identified and two tiny parasitic wasp species were found and collected from Guatemala by the HDOA's exploratory entomologist.