Plant Industry - Plant Protection Section

On the first of November, 1993, ash whitefly infestations were detected in downtown Raleigh, North Carolina. The ash whitefly, Siphoninus phyllyreae (Haliday),is native to much of Europe and Northern Africa. It was first detected in the United States in 1988 in California. Since that time it has spread across the U.S., most likely via infested nursery stock. The ash whitefly can be economically damaging to the agricultural industry, particularly the production of apples, citrus, and pomegranate. This pest also infests several ornamental trees and shrubs, such as; ash, Bradford pear, Pyracanthas, Photinia, and Malus spp. Infestations are considered heavy in the Raleigh area.

The NCDA&CS has initiated a biological control program to slow the spread and to reduce the population size of ash whitefly. Encarsia inaron (Walker) is a tiny wasp which parasitizes ash whitefly late instar larvae. The Encarsia wasp has been used successfully to control the ash whitefly in California where it resulted in a 1,000 to 10,000 fold reduction in the ash whitefly population within two years.

In the absence of its natural enemies, the ash whitefly exhibits tremendous population growth. It is the goal of the NCDA&CS Biological Control Program to release the Encarsia wasp in infested areas of North Carolina to prevent the populations of ash whitefly from reaching economically damaging levels. Encarsia wasps are currently be reared in a facility on Dorthea Dix Hospital property, and additional shipments of this effective natural enemy are being received from U.C. Riverside, Riverside California. The NCDA&CS is optomistic about the imminent control of ash whitefly populations in North Carolina, and its ability to provide assistance to other agencies, and individuals attempting to control the ash whitefly.