Spruce budworm deterrents

Bentley, M. D., Leonard, D. E., Stoddard, W. F. and Zalkow, L. H. (1984). Pyrrolizidine alkaloids as larval feeding deterrents for spruce budworm, Choristoneura fumiferana (Lepidoptera Tortricidae). Annals of the Entomological Society of America 77 393-397. 

Tomatidine (298) was found to be a feeding deterrent to sixth instar larvae of the spruce budworm Choristoneura fumiferana [658] and it strongly inhibited growth in the Xenopus embryo teratogenesis assay [651]. The 3-oxo derivative of 298, and the 23-acetoxy derivative have been isolated from roots of a hybrid of Lycopersicon esculentum x L hirsutum [640],... 

The importance of the 15,16 double bond of esterified pyrrolizidines was also borne out in a study using the spruce budworm larvae (Choristoneura fumiferana) as a model test system (see Table 2.1). Anti-feeding behavior was recorded for a variety of alkaloids and plant extracts containing alkaloids (1). Of the 14 pyrrolizidine alkaloids examined, only two, senkirkine and lasio-carpine, were highly deterrent (> 75%). When the stereochemistry of the 15,16 double bond of these compounds was modified, as in the case of neosenkirkine, or the double bond was epoxidized, as in otosenine, the deterrent activity of the alkaloid was decreased dramatically. This is in sharp contrast to the increase of toxicity associated with epoxide formation in the case of jacobine... 

James A. Saunders, Nichole R. O Neill, and John T. Romeo Table 2.1. Alkaloids tested against the spruce budworm for feeding deterrency at 0.5 mg/ml ... 

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