LIFE-HISTORY TRAITS OF THE WHITEFLY, BEMISIA-TABACI (HOMOPTERA, ALEYRODIDAE) ON 6 VIRUS-INFECTED OR HEALTHY PLANT-SPECIES

In some cases, infection by plant viruses can alter host plant quality for homopterous insects. In these experiments, adult whiteflies from a population of Bemisia tabaci (Gennadius) that had been reared continuously on pumpkin plants for more than five years, were exposed to six plant species infected with one of four whitefly-transmitted plant viruses. The life history traits of whiteflies on virus-infected hosts were compared to those of whiteflies exposed to corresponding healthy hosts. Significant differences were found in progeny survival and oviposition rate among the six healthy hosts. Survival on healthy hosts ranked as follows: zucchini > cantaloupe = cotton = pumpkin > lettuce = tomato. Oviposition and immature survival rates varied between healthy and virus-infected host plants. The mean proportion of eggs surviving to adulthood was higher on pumpkin plants infected with watermelon curly mottle strain of squash leaf curl virus (WCMoV/SLCV) than on healthy pumpkin. Significantly lower mean proportion of offspring survived to adulthood on WCMoV/SLCV-infected zucchini, chino del tomate virus-infected tomato, and cotton leaf crumple virus-infected cotton compared to whiteflies on healthy control plants. For other virus-infected-healthy combinations, there were no significant differences in survival rates. No correlation was observed between levels of total free amino acids in healthy and infected plants and rates of oviposition or survival. The lack of correlation between oviposition and survival rates on healthy and infected plants, suggests that B. tabaci does not assess host suitability to regulate oviposition with respect to the projected host suitability for offspring survival.