Repellency, toxicity, and oviposition inhibition of vegetable extracts against greenhouse whitefly Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae)

In a search for sustainable options of greenhouse whitefly Trialeurodes vaporariorum (Westwood) management, the toxic and/or repellent potential of water, ethanolic, and acetonic extracts of Ambrosia artemisiifolia L. (Asteraceae), Comocladia engleriana Loes (Anacardiaceae), Piper auritum Kunth (Piperaceae), Raphanus raphanistrum L. (Brassicaceae), and Taraxacum officinale F.H. Wigg. aggr.* (Asteraceae) were evaluated. Repellency was assessed by the cylinder method (olfactometer), while toxicity and oviposition inhibition were assessed by the leaf immersion method. Acetonic extracts did not cause any repellent or insecticidal effect. In contrast, 200 mg mL(-1) water and ethanolic extracts of R. raphanistrum and ethanolic extract of A. artemisiifolia had the highest repellent activity (76%, 72%, and 69%, respectively) although their activity decreased gradually over time. Ethanolic extracts of P. auritum (66%) and R. raphanistrum (56%) at 200 mg mL(-1) were highlighted as being toxic, while the most effective in inhibiting oviposition were water extracts of R. rap hanistrum (76.1%) and P. auritum (72.0%) and ethanolic extract of P. auritum (69.5%); however, concentrations lower than 60 mg mL(-1) caused oviposition stimulation. Our results suggest that water and ethanolic extracts of R. raphani strum and P. auritum represent a useful tool in integrated whitefly management.