Whitefly population fluctuation and golden mosaic incidence in bean

Abstract

Bean golden mosaic (BGMV) is an economically pernicious disease in Latin America, especially in Brazil. With the objective of studying the fluctuation of the vector population and its relation to the variation of bean golden mosaic incidence and to the climatic conditions (temperature and rain), this research was carried out from 1994 to 1995. Early in September, the whitefly population sizes were small, but increased steadily up to February, when the bean golden mosaic incidence was also at high levels. In March, even with high vector populations moving from soybean fields, there was no increase in this disease incidence, which indicated that a greater proportion of the flies were not virulent. The decrease in vector population was related to low temperatures, specially to the minimum temperatures in April; nevertheless, the bean golden mosaic incidence was constant. It was concluded that small whitefly populations may be sufficient to promote BGMV epidemics, given that the number of virulent whiteflies rise due to successive bean plantings in time and to the presence of the virus/vector hosts.