[Bemisia tabaci, the vector of bean golden mosaic virus]

The information that exists for Bemisia tabaci (Gennadius) as a vector of bean golden mosaic virus (BGMV) is fairly limited. Although 5 species of whiteflies (Homoptera: Aleyrodidae) have been identified from beans in the Americas, only B. tabaci is confirmed as a vector of BGMV. There are reports that numerous biotypes of B. tabaci (A,B,C,D,G) are present in Central America and the Caribbean basin, but these conclusions are premature. Additional research is needed on biotypes, in general, in Latin American and specifically on the biotype(s) associated with bean plantings. The only detailed study on the biology of Bemisia tabaci in beans comes from research at CIAT. The development time for B. tabaci on beans under greenhouse conditions (26 degrees C) was found to be 30.3 days. Average adult longevity was 11 and 14 days for males and females, respectively. And, females laid an average of 76 eggs during their lifetime. Under field conditions in the Dominican Republic and Brazil, B. tabaci reproduces abundantly on beans. However, both CIAT studies and field observations from Mexico and Central America suggest that beans are not a good reproductive host for B. tabaci. In these latter cases, it is probably other cultivated host plants that serve as reproductive hosts for the whitefly. In Central America B. tabaci can complete its life cycle on, at least, 14 cultivated plants. The crop plants should be studied to determine their relative importance as reproductive sources for Bemisia. Bemisia tabaci develops between 10.0 and 32.2 degrees C, reaching high populations levels under hot, dry conditions. The most important factor in reducing whitefly population levels appears to be rainfall. High levels of rainfall have been linked to low whitefly populations in many crops, world-wide, including bean-producing zones in Latin America. The contribution of entomologists to the understanding of Bemisia tabaci as a vector of bean golden mosaic virus (BGMV) and the development of crop protection strategies to manage the whitefly has been extremely limited. This has been true in part because the principle tactic promoted for BGMV protection has been the deployment of resistant varieties, and because entomologists continue to treat insect vectors as if they were insect pests. Consequently, the conventional strategy of reducing whitefly populations in the bean fields with insecticides has predominated. Chemical control is the predominant form of vector managament in Latin America and the Caribbean with IPM, i.e. insect pest, style economic injury levels established at low population densities (e.g. 0.5 whiteflies/plant in Cuba), and frequent insecticide applications (e.g. 12-14 per growing season in Guatemala). An alternative approach, based on epidemiological analysis using a mathematical model is presented