Effects of a mixture of vegetable and essential oils and fatty acid potassium salts on Tetranychus urticae and Phytoseiulus persimilis.
Laboratory trials were carried out to evaluate the toxicity and the influence of a commercial mixture of vegetal, essential oils, and potassium salts of fatty acids (Acaridoil 13SL) on the population growth rate (r(i)--instantaneous rate of increase) of two mite species, the phytophagous Tetranychus urticae Koch and the predator Phytoseiulus persimilis Athias-Henriot. A residue of 1.3 mg/cm(2) of pesticide solution was harmless for Ph. persimilis eggs, while a moderate mortality of eggs and of larvae from treated eggs of T. urticae, was observed (53.8%). The pesticide also caused a delay in the postembryonic development of the tetranychid. Moreover, 83.4% mortality was reported for treated females tetranychids and only 24.0% for Ph. persimilis females. The pesticide influenced negatively the population growth of T. urticae which showed a very low rate of increase (r(i)=0.07), compared to that obtained in the control (r(i)=0.68). The pesticide did not affect negatively the reproductive potential of Ph. persimilis (r(i)=0.54 and r(i)=0.57 for test and control, respectively). These results suggest a considerable acaricidal activity of potassium salts of fatty acids and caraway oil on T. urticae and a good selectivity on Ph. persimilis.
Tsolakis
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Dipartimento S.EN.FI.MI.ZO., Sezione di Entomologia, Acarologia e Zoologia, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy. tsolakis@unipa.it
Ragusa
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D000818:Animals; D005227:Fatty Acids / Q000633:toxicity*; D005260:Female; D007306:Insecticides / Q000633:toxicity*; D008297:Male; D008925:Mites / Q000187:drug effects* / Q000502:physiology; D009822:Oils, Volatile / Q000633:toxicity*; D010058:Oviposition / Q000187:drug effects; D010938:Plant Oils / Q000633:toxicity*; D011158:Population Growth; D011188:Potassium / Q000633:toxicity*; D012492:Salts / Q000633:toxicity; D015053:Zygote / Q000187:drug effects; D029974:Carum
D005227:Fatty Acids; D007306:Insecticides; D009822:Oils, Volatile; D010938:Plant Oils; D012492:Salts; C104525:caraway oil; D011188:Potassium