Whitefly (Bemisia tabaci Genn) populations were monitored in La Huerta and Casimiro Castillo, Jal, Mexico at different planting dates (From September to January) of winter irrigated watermelon. Ten plots under grower’s conditions were weekly sampled for two consecutive years (1998-01). Adults were sampled by using five yellow water traps/plot and immature stages (nymphs) present on leaves from 10 plants per each of five places into the plot. Virus infection was monitored by counting infected and non-infected plants from three 10-m rows in five places into the plot. Whitefly populations were high in plots planted from September to mead October. The lowest population was recorded in plots planted in late October to early November. Again high populations occurred in those plots planted in December or later. Whitefly population and the proportion of infected plants always had the same pattern. In plots planted at early dates, whitefly populations and proportion of infected plants increased gradually as the crop was growing, reaching the peak at harvest time. However, at late planting dates, high whitefly population and infected plants were detected before or at flowering. Immature stages were very low at different planting time of the crop, probably because of the high frequency of insecticide applications. Levels of infected plants were according with whitefly adult populations. The lowest proportion of infected plants occurred in plots planted from September to early November, and the highest proportion was recorded in plots planted after mead November (sometimes levels reached 100 % of infected plants). The severity of the infection was also higher in late than in early planted plots. Pest population and infected plants increased not only as planting date was later, but also as white fly’s host weeds and temperature increased from winter to spring.
Species 1: Homoptera Aleyrodidae Bemisia tabaci Genn (whiteflies)
Keywords: Whitefly, watermelon
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA