The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), a phloem feeding insect, is one of the most economically damaging agricultural crop pests worldwide. Yield of Cucurbita plants is reduced by B. tabaci through direct feeding, transmission of viruses, and physiological disorders. Feeding by B. tabaci nymphs causes squash silverleaf (SSL) disorder in plants in the genus Cucurbita . Leaves of Cucurbita plants fed on by nymphs change from a healthy green to a silvery appearance. The severity of SSL disorder can be reduced by reducing the population of this pest by cultural, chemical, biological control, and host resistance. Genetic studies have shown that SSL disorder resistance is controlled by a single recessive gene, sl , along with modifying genes in both C. pepo and C. moschata. Leaf variegation with a silvery appearance also occurs in Cucurbita in the absence of B. tabaci . We revisit earlier studies that suggested that this silvering in Cucurbita is associated with insect non-preference and hypothesize that SSL disorder might be a defense response mimicking leaf variegation.
Luckew et al. (Fri,) studied this question.