NOVEL SUCROSE ESTERS FROM NICOTIANA-GOSSEI - EFFECTIVE BIORATIONALS AGAINST SELECTED HORTICULTURAL INSECT PESTS

Leaf-surface extracts of Nicotiana gossei Domin, N. benthamiana Domin, and N. bigelovii (Torrey) Watson were the most active of those from 1 7 species of Nicotiana evaluated against late second/early third insta rs of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). F our chromatographically purified sucrose esters of N. gossei resulted in 88-94% mortality of late second/early third instars of the sweetpot ato whitefly, Bemisia tabaci (Gennadius). A less purified mixture of t he four compounds was effective at 1.0 mg/ml (wt:vol) against nymphs o f both whitefly species and the green peach aphid, Myzus persicae (Sul zer), and it deterred feeding and oviposition by the twospotted spider mite, Tetranychus urticae Koch. These sucrose esters were not active against whitefly eggs; neonates of the Colorado potato beetle, Leptino tarsa decemlineata (Say); or second instars of the western flower thri ps, Frankliniella occidentalis (Pergande). The selective activity agai nst immature insects, and the feeding and ovipositional deterrence to spider mites suggest pesticidal activity. Activity of 1.0 mg/ml (wt:vo l) aqueous mixtures of the four compounds was comparable with, or bett er than, label rates of currently available biorational products or pe sticides. The purified product was stable for 1 yr.