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Effects of insect growth regulators on the hairy rose beetle, Tropinota squalida (Col., Scarabeidae)
- Hussein, H.M., Dimetry, N., Zidan, Z., Iss-hak, R.R., Sehnal, F.
- Journal of applied entomology 2005 v.129 no.3 pp. 142-148
- azadirachtin, experimental diets, Scarabaeidae, hormone agonists, saponins, insect development, hydroprene, insect reproduction, mortality, topical application, insect control
- Saponin extract from alfalfa roots, azadirachtin from the neem seed oil, synthetic ecdysteroid agonist RH-2485, and the juvenoid hydroprene disturb the development and reproduction of Tropinota squalida. Feeding beetles on diets containing 750 p.p.m. saponins, 7.5 p.p.m. RH-2485, and 1.13 p.p.m. azadirachtin reduces their progeny from 51 second instar larvae per female to 24, 15, and 15 larvae, respectively. When the larvae of untreated adults are fed for 1 week on dung with 75 p.p.m. saponins, 50 p.p.m. RH-2485, and 0.45 p.p.m. azadirachtin, the rate of adult emergence drops from 80% (controls) to 20, 0 and 13%, respectively. No adults emerge when the treatment is continued through the second and third larval instars. Two topical treatments of larvae with 0.2 microgram hydroprene decrease the rate of adult emergence from 90 to 11%, and treatments with 2 microgram prevent adult development in all insects. The observed effects warrant testing of azadirachtin, RH-2485, and hydroprene in the field. Several types of their application for the control of T. squalida are suggested.