Insecticidal and antifeedant

Destruxins and bassianolide have no importance in practical plant protection because their recovery is cumbersome, they are highly toxic to warm-blooded animals and, moreover, they are not contact poisons. Their activity as a stomach poison is greatly limited by their antifeedant effect. They are primarily products of theoretical interest, and it is to be hoped that study of them will clarify relationships concerning the mechanism of the insecticidal and antifeedant effects, and will help elucidate the biological effect of cyclodepsipeptide antibiotics of similar structure. 

Escoubas, P. Lajide, L. Mizutani, J. Insecticidal and antifeedant activities of plant compounds potential leads for novel pesticides., American Chemical Scociety Washington, DC, 1994 Vol. 551, pp 162-71. 

Products isolated from plants of the Celastraceae family have showed insecticidal and antifeedant activities, as discussed earlier. The compounds reported belong to the agarofuran sesquiterpene-type and sesquiterpene pyridine-type alkaloids. Nevertheless, the only description of insecticidal activity of quinone methides found is from Avilla et al [102], Despite the fact that the compounds assayed were known the... 

Fig. (6). Insecticidal and antifeedant sesquiterpenes from some Celastrus species...

Plant sesquiterpenes and other terpenoids aie major detenninants of insect-plant interactions (2i 16V Many insecticidal and antifeedant terpenoids are epoxides including monoteipene Q2, 18. sesquiteipene QQ, 19-23). diteipene (Jl, 24) and triteipene derivatives (25-27) typified by the potent antifeedant azadirachtin (28-30). Most biolo cal effects have been determined with Lepidoptera and non-chrysomelid Coleoptera. Occasionally, the same compound, while normally inhibitory to herbivores, may for adapted insect species or at low concentrations have a stimulatory effect (13). Insects, in turn, synthesize their own defensive (21, and pheromonal (22) terpenoids. Plants may utilize insect pheromones such as the sesquiterpene alarm pheromone, rranj-B-famesene, in their own defense (34. 35). Inhibitory cyclic sesquiterpenes (Table I) and diterpenes (Table II) for insect herbivores have been identified from at least 28 genera of the terpenoid-rich Compositae. These studies were largely confined to extrafloral tissues. 

Reed, D. K., B. Freedman, and T. L. Ladd Jr., Insecticidal and antifeedant activity of neriifolin against codling moth, striped cucumber beetle, and Japanese beetle, J. Econ. Entomol, 75, 1093-1097 (1982). 

A number of limonoids and quassinoids from the Rutaceae, Meliaceae, and Simaroubaceae are insect antifeedants. These compounds have been extensively investigated, as they may provide relatively specific, biodegradable insecticides and antifeedants. 

Klocke, J. A., M. Arisawa, S. S. Handa, A. D. Kinghorn, G. A. Cordell, and N. R. Farnsworth, Growth inhibitory, insecticidal and antifeedant effects of some antileukemic and cytotoxic quassinoids on two species of agricultural pests, Experien-tia, 41, 379-382 (1985). 

M. B. O. Isman et al. Insecticidal and antifeedent activities of neem oils and their relationship to azadirachtin content. J Agriculture Food and Chem, 38,1406, 1990. 

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