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Evaluation of the insecticidal properties of the green alga, Scenedesmus acutus against the Egyptian cotton leafworm Spodoptera littoralis (Boisd)
Published online by Cambridge University Press: 19 September 2011
Abstract
Successive extraction of the green alga, Scenedesmus acutus 276–3a with different solvents indicated that the petroleum ether extract was the most repellent to the hatched larvae of Spodoptera littoralis. The application of spray emulsified 1 % petroleum ether extract inhibited egg laying. At 0.25% concentration the moths laid only 52.4 of their egg masses on the treated oviposition sites in comparison to the untreated control. Concentration of 1% was protective against the immature stage by hindering the third instar larvae to feed on treated leaf discs. In addition, the water emulsion of petroleum ether extract was insecticidal. The percentage mortality was directly proportional to the concentration applied and to the duration of exposure.
Résumé
L'extraction successive de l'alge verte Scenedesmus acutus 276-3a avec des different solvents montre, que l'extrait du l'ether fretrole e'tait le plus reperable aux larves obtenues de Spodoptera littoralis. Des concentrations different de l'extrait d'ether petrole etaient examines pour la diminution ovipositionale, l'activite contre le manger et l'ecaractere insecticide contre les insectes qui attacquent les feuilles du cotton Spodoptera littoralis. Les resultats obtenus montrent que 1 % concentration de l'eau emulsifie de l'extrait de 1'ether petrole diminue le nombre des oeufs. A concentration e'gale 0, 25% la mere donne seulement 52, 4 de leur oeufs, sur les ovifroitions traits en comparant au control pas traites. 1% concentration agie comme une concentration protegante contre l'etat pas bien developé et cela en prevenant la troisieme de la larve de manger les disques des, feuilles traites. En plus l'eau emulsifie de l'extrait de 1'ether petrole etait insecticide dans un pourcentage de mortalite qui est directement proportional à la concentration appliquee et la duree de l'exposition.
- Type
- Research Articles
- Information
- International Journal of Tropical Insect Science , Volume 14 , Issue 5-6 , December 1993 , pp. 615 - 619
- Copyright
- Copyright © ICIPE 1993
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