Choice of ovipositional site of Bemisia tabaci on vegetables
In order to design efficient sampling procedures for Bemisia tabaci (EPPO A2 quarantine pest), it is considered essential to know where its immatures stages can be found on the plant. Selection of ovipositional site by B. tabaci strain B (B. argentifolii) has been studied on 10 vegetable crops: Cucumis melo (melon), Cucumis sativus (cucumber), Solanum melongena (aubergine), Capsicum annuum (pepper), Brassica oleracea ssp. acephala (cabbage), Vigna unguiculata (cowpea), Phaseolus vulgaris (bean), Cucurbita pepo ssp. melopepo (summer squash), Lycopersicon esculentum (tomato) and Citrullus lanatus (watermelon) under field, greenhouse and laboratory conditions. The results showed that feeding and oviposition started on the cotyledons and then continued on the subsequent immature leaves, but no oviposition was observed on cotyledons of Vigna unguiculata and Phaseolus vulgaris. On most crops, 90-95 % of the eggs were laid on the lower surface of the leaves. In laboratory tests on four species (Cucumis melo, Cucurbita pepo ssp melopepo, Phaseolus vulgaris and Vigna unguiculata), eggs are mostly laid on leaves positioned at the top of the plant (strong negative geotropic response). The author felt that during sampling, consideration should be given to immature stages present on the lower leaf surface.
Sources
Simmons, A.V. (1994) Oviposition on vegetables by Bemisia tabaci (Homoptera: Aleyrodidae): temporal and leaf surface factors.
Environmental Entomology, 23 (2), 381-389.