Experiments were conducted in the laboratory and the greenhouse to assess the effects of five acaricides against Tetranychus urticae Koch and its natural enemy Phytoseiulus persimilis Athias-Henriot. The acaricidal activity of the tested compounds against T. urticae was assessed by the slide dip and leaf disk dip techniques. Data showed that slide dip technique was efficient method to screen abamectin, chlorfenapyr and fenpyroximate; while the leaf disk dip technique was efficient method to determine the toxicity of ethion and etoxazole. The difference between the compounds may be due to their mode of actions. Results indicate that ethion, chlorfenapyr and etoxazole are very less toxic to P. persimilis adult females than those of T. urticae. Direct count for each of the prey and predator in order to assess the impact of compounds tested under greenhouse conditions, confirmed the results obtained to a large extent in the laboratory experiments.
Two experiments were conducted in Baramoon Research Station, Dakahlia Governorate, Egypt during the growing summer seasons of 2014 and 2015 to determine the effect of some exogenous plant extracts to control mechanical injured, pest management, increasing productivity and storability of potato plants. Five locally available plants namely, neem, liquorice, turmeric, pomegranate and thyme were evaluated plus check treatment. Foliar spray with pomegranate peels or liquorice extracts (5%) led to significant increases in all vegetative growth parameters, total tuber and marketable yields and decreases in all physiological disorders and mechanical injures of potato plants. All the treatments were significantly reduced in population density of two spider mite, aphids and whitefly. The most effective treatments were turmeric, thyme and neem extracts for previous mentioned three insects, respectively, in terms of reduction percentage. Application of pomegranate or thyme extracts were significantly reduced percent of weight loss and decay, also excelled at increasing the content of dry matter and starch over the control and other treatments during storage at 4 o C. The control treatment or neem extract had significant reduction the content of total phenols and the activity of polyphenol oxidase enzyme.This study recommends using foliar application with pomegranate peels or licorice extracts to increase the productivity, quality and marketable yield and neem or thyme extracts as pesticides and pomegranate peels or thyme extracts to increase storability and reduce weight losses, at intervals of 15 days beginning from the first of March until the end of April.
The biology of Agistemus exsertus Gonzalez was studied using five different types of diets, eggs and nymph of Tetranychus urticae Koch, eggs and larva of Bemisia tabaci, and eggs of Ephestia kuehniella as the food source. The development was faster and reproduction was higher when A. exsertus fed on eggs of E. kuehniella. A diet of T.urticae, eggs provided the longest female longevity and mean total fecundity which resulted in the highest net reproductive rate (R 0) value (93.71), intrinsic rate of natural increase (r m = 0.25), finite rate of increase (e rm = 1.28) per day , and Gross reproduction rate (GRR =104.8) for A. exsertus.whereas the lowest value of all parameters achieved with a diet of B. tabaci larva.
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