Beet army worm

Ritter, F. J., Briiggemann, I. E. M., Gut, J., and Persoons, C. J. (1982). Recent pheromone research in the Netherlands on muskrats and some insects pests introduced from America into Europe the muskrat, Odatra zibethicus, the American cockroach, Peri-planeta americana, and the beet army worm, Spodoptera exigua. American Chemical Society Symposium Series 190,107-130. 

A new member of the tartrolon series of macrodiolides, tartrolon C (17), was isolated from a Streptomyces species on the basis of its insecticidal activity [56]. The producing organism was isolated in 1990 from a soil sample collected near Braunschweig, Germany. Tartrolon C was active on the beet army worm and tobacco bud worm, with minimum emergent larvicide concentration of 125 ppm on both insects, approximately 40 x and 310 x less active than a standard of spinosyn A. 

C23H38N2O5, Mr 422.47, amorphous solid. Beet army-worm caterpillars supply their plant host with a suicide weapon called V. (induced chemical defense in plants). V. is the A( -( 17-hydroxylinolenoyl) derivative of L- "glutamine. When some plants, such as com, are injured by the caterpillar s feeding, V. in damaged tissues signals the plant to emit volatile compounds that attract wasps, the caterpillar s natural enemy. V. appears to be a natural product of the caterpillar, rather than of the plants. 

One effect of these chemical modifications is that DE-175 is intrinsically more active against pest insect species than spinosad. For example, in a laboratory bioassay of topical toxicity to beet armyworm Spodoptera exigua) larvae, DE-175 is 48X more active than spinosad (Table 29.3.3). Similar results are observed in a bioassay of ingestion activity, where DE-175 is 58 x more active on beet army-worm than spinosad. Improved potency of DE-175 is also observed against other lepidopterous insects, though to a lesser degree (Table 29.3.3). 

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