Cut-shoot bioassay test was used to study the significance of three flavonoids as aphicides against the woolly apple aphid (WAA), Eriosoma lanigerum (Hausmann). The used flavonoids were two flavanols that are quercetin dehydrate and rutin hydrate, but rutin hydrate is a glycoside of quercetin dehydrate. In addition to one flavanone that was naringine. These flavonoids were used at three concentrations; 100 ppm, 1000 ppm and 10,000 ppm. Results showed that the three tested flavonoids were active as aphicides against the target species and that mortality to nymphs was higher than that obtained against apterous adults. Increasing the concentration of the flavonoids resulted in a remarkable increase in nymphs mortality. However, rutin hydrate is more toxic to WAA than quercetin dehydrate and naringin.The three flavonoids had slight effect on the sole parasitoid of WAA, Aphelinus mali compared with effect caused by imodacloprid insecticide. Quercetin dehydrate, rutin hydrate and naringine can be used as botanical insecticides and incorporated into integrated management programs of the aphid.
Aqueous extracts of nine plants, known to have medicinal activity, were tested for their toxicity against the sweet potato whitefly, Bemisia tabaci Genn. (Homoptera: Aleurodidae) compared to the toxicity of the insecticide, Imidacloprid. Extracts of Lepidiuim sativum L. (Brassicales: Brassicaceae) killed 71 % of early stage nymphs, which was not significantly different from mortality caused by Imidacloprid. Treatment of pupae with three plant extracts, L. sativum, Achillea biebersteinii L. (Asterales: Asteraceae), or Retama raetam (Forssk.) Webb and Berthel (Fabales: Fabaceae) prevented adult development, and treatment with R. raetam extract killed adults, at levels that were not significantly different from Imidacloprid. None of the other plants showed significant toxicity. However extracts of four plants, Pimpinella anisum L. (Apiales: Apiaceae), Galium longifolium (Sibth. and SM.) (Gentianales: Rubiaceae), R. raetam and Ballota undulata Bentham (Lamiales: Lamiaceae) had a repellent effect.
Toxicity and repellent activities of aqueous extracts of nine medicinal plants were evaluated on diVerent life stages of the sweet potato whiteXy, Bemisia tabaci. Tomato plants infested with whiteXies were dipped in 10% (wt/wt) of each plant extract for toxicity evaluation. Repellency was evaluated in a choice experiment with detached tomato leaves. All extracts evaluated were relatively ineVective against the adult stage. Extracts of Ruta chalepensis, Peganum harmala and Alkanna strigosa were eVective in reducing the numbers of B. tabaci immatures similar to the reduction observed in the imidacloprid treatment. These three extracts were not detrimental B. tabaci parasitoid, Eretmocerus mundus. In addition, the plant extracts Urtica pilulifera and T. capita were repellent to B. tabaci adults. These results indicate that the extracts from the plants R. chalepensis, P. harmala and A. strigosa could act as a potential source for natural product developed for B. tabaci management.
Experiments were conducted in Ash-Shoubak area of Jordan from June 2003 to September 2005 to study the effect of three apple rootstocks on the development of the small red-belted clearwing borer, Synanthedon myopaeformis (Borkh.) (Lepidoptera: Sesiidae), under field conditions. Mondial Gala apple trees grafted on the dwarfing rootstock M9 and the semi-dwarfing rootstock M26 were equally infested, whereas those grafted on MM106 showed significantly lower infestation levels. S. myopaeformis bore into burr knots that develop below a graft union on rootstocks and girdle the tree. There was a significant effect of rootstock on the numbers of burrs present, and the percentage of burr knots infested by S. myopaeformis, with M106 having significantly fewer burrs, and a lower percent infested.
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