Trends in the Temporal Distribution and Host Plant Relations During 1988-1994, and Virus-vector Characteristics of Two Whitefly Populations in Arizona

Abstract

The abrupt and widespread introduction and establishment of the B type whitefly B. tabaci (Genn.) (also B. argentifollii) in Arizona in approximately 1987-1990 has given rise to unprecedented losses in vegetable and fiber crops in Arizona, and elsewhere throughout the sunbelt states. This report documents the discovery and the tracking of B type whitefly over time in Arizona crop and weed species, and reports important biological characteristics of the A and B whitefly populations with respect to host range, host preferences, and virus-vector capabilities. Here, from tracking data, we provide direct evidence that the A and B whitefly populations existed simultaneously in the state for a short period of time during 1989-90, and that by 1991, the B type population had become predominant whitefly pest and whitefly vector of plant viruses in Arizona crops. Unique host ranges and host preferences represent the most important distinctions between these two populations of B. tabaci, and are largely responsible for the altered epidemiologies of several whitefly- associated virus diseases, and for new pest problems in previously unaffected crops. From these collective data, it is possible to present an historical documentation of the emerging importance of the B whitefly as a pest and virus vector in Arizona. An unusually broad host range and the ability to induce phytotoxic disorders, set the B population apart from the historically problematic, local A type B. tabaci, and provide insights into the underlying basis of its unprecedented impact on crop production in Arizona. Baseline information about whitefly biology, host range, and virus-vector capabilities is relevant to the design and implementation of management practices aimed at controlling the whitefly as a pest and virus vector in Arizona crops.