Study of Host Preference and the Comparison of some Biological Characteristcs of Bemisia Tabasi (Genn) on Tomato Varieties

The resistance of 8 tomato varieties to cotton white fly, Bemisia tabaci (Genn) (Hemiptera: Aleyrodidae), was evaluated in four greenhouse experiments. In the first experiment, we evaluated the attractiveness and preference for oviposition in a free-choice test (randomized blocks, 8 treatments, and 5 replications). In the other experiments, we evaluated the no-choice preference for oviposition (randomized blocks, 4 treatments, and 4 replications). The whitefly egg-adult cycle was monitored using a statistical design in randomized blocks with four replications. The percentage mortality of immature stages was also determined (randomized blocks with four replications). In the free-choice test, the tomato variety Rio Grande was the most attractive to adults, while the variety Cheffalat had the lowest number of adults. Also in this assay, the variety CAL-JN3 presented the lowest number of eggs, while the variety Ergon presented the highest number of eggs. In the no-choice test, the varieties Chef-falat and CAL-JN3 remained resistant. Consequently, for these two varieties non-preference is the oviposition resistance mechanism. The egg-adult cycle varied from 26.02 days (Ergon) to 26.66 days (CAL-JN3). The total mortality varied from 20.52 (Ergon) to 33.97 (CAL-JN3). Considering all the characteristics, the variety CAL-JN3 was the most resistant to B. tabaci among all the tomato varieties studied, while variety Ergon was susceptible.