Insecticidal activity of natural and synthetic sugar esters against Bemisia argentifolii (Homoptera: Aleyrodidae)

Insecticidal activities of natural sugar ester isolates of Nicotiana spp. and synthetic sugar esters were tested against Bemisia argentifolii Bellows & Perring in laboratory bioassays and a tomato field trial on staked tomato. A mixture of the pyrethroid cyfluthrin and methamidophos, as well as the juvenile analog pyriproxyfen, were used for comparison in the field trial. Mortality of adults immobilized on yellow sticky cards and sprayed to run-off (approximate to 100% coverage) with sugar ester isolates of Nicotiana spp. (including N. gossei) approached 100%. In contrast, mortality of immobilized adults heated in a Potter spray tower (approximate to 70% coverage) with the same concentrations of N. gossei was <50%. Sugar ester isolates of N. gossei, N. amplexicaulis, N. glutinosa, N. langsdorffii, N. trigonophylla, and N. palmeri and a synthetic sucrose ester were more toxic to 2nd-instar nymphs at a rate of 1 g (AI)/liter than were isolates of N. cavicola, N. simulans, N. pauciflora, N. plumbaginifolia, N. noctiflora, and N. otophora. Whitefly populations on tomato sprayed weekly in the field with a sugar ester isolate of N. trigonophylla or 4 synthetic preparations were reduced by 40-98% for immatures and 43-73% for adults compared with untreated plants. Sugar ester isolate and synthetic sugar esters in the field tomato trials compared favorably with commercial insecticides for whitefly control.