Tolerance of the Egyptian cotton leafworm Spodoptera littoralis (Lepidoptera: Noctuidae) to ingested phytoecdysteroids

Distribution and metabolism of exogenous ecdysteroids in the egyptian cotton leafwormSpodoptera littoralis (lepidoptera: noctuidae)

“…We have demonstrated that Spodoptera littoralis is resistant to ingested exogenous ecdysteroids and is able to tolerate both prolonged exposure to 100 ppm 20E and single-dose administration of 10 µg E or 20E (Blackford et al, 1996). In addition, we have shown that larvae feed readily and develop normally on Chenopodium album, a plant containing high levels of high levels of 20E and polypodine B.…”

Creation of ecdysone receptor chimeras in plants for controlled regulation of gene expression

“…RH5992 is a non-steroidal agrochemical, is highly speci®c for lepidopteran ecdysone receptors and has a fa- (Heller et al 1992). Although ecdysteroids are found in plants, most crop plants have low or undetectable levels of ecdysteroid agonists, as assayed in Drosophila Kc cell-based assays or by radioimmunoassays (Blackford et al 1996;Blackford and Dinan 1997). RH5992 was shown to have a dose-dependent eect on maize protoplasts co-transformed with reporter and chimeric receptor containing the Heliothis receptor (Fig.…”

Biological activity of natural phytoecdysteroids from Ajuga iva against the sweetpotato whitefly Bemisia tabaci and the persea mite Oligonychus perseae

“…Previous studies have demonstrated the potency of ecdysteroids from plants on a number of lepidopteran pests. These pests include some very economically important ones that are known for their ability to detoxify chemical insecticides, including S. frugiperda, Pectinophora gossypiella ,6 Acrolepiopsis assectella ,25 A. urticae and I. io ,11 while other species showed complete tolerance to these phytoecdysteroids, including H. virescens ,12 H. armigera 13 and S. littoralis 14. The data presented in the present study demonstrate that, in the concentrations studied, the mortality, fecundity and fertility of both B. tabaci and O. persea , two economically important agricultural pests, are affected by ecdysterone and sometimes cyasterone.…”

“…The effects included inhibition of growth and induced death before or after moulting. Certain insect species were not affected after phytoecdysteroid application such as in Heliothis virescens ,12 Heliothis armigera ,13 Spodoptera littoralis 14 and Lacanobia 15. In these species, detoxification mechanisms were able to overcome the applied exogenous phytoecdysteroids.…”