Margosan‐O and Neem azal‐S two commercial preparations of neem seed kernel extract were tested for their effect as deterrent, toxicant and growth inhibitor against the two spotted spider mite Tetranychus urticae Koch. Both formulations exhibited strong deterrent effect for T. urticae females. ODI was maximum 100% in case of Neem azal‐S and 80.95% for Margosan‐O at (0.4%) conc. Leaf discs treated with different concs. of the two products showed increased mortality and retarded development. A significant reduction in the total no. of eggs laid as well as a decrease in the percentage of egg hatchability was observed. Zusammenfassung Zur Wirkung von zwei Neem‐Samenextrakten auf die Spinnmilbe Tetranychus urticae Koch Es wurden Margosan‐O und Neem‐Azal‐S, zwei kommerzielle Praparate aus Neemsamen‐Extrakten hinsichtlich ihrer abschreckenden, toxischen und wachstumshemmenden Wirkung auf die Spinnmilbe T. urticae untersucht. Beide Formulierungen zeigten abschreckende Wirkung auf die Spinnmilben‐Weibchen. Der ODI‐Wert betrug 100% beim Einsatz von Neem‐Azal‐S und 80.95 YO bei Margosan‐O (je 0,4% Konz.). Blattausschnitte, die mit verschiedenen Konzentrationen der beiden Produkte behandelt worden waren, zeigten zunehmende Mortalitat und Entwicklungshemmung. Weiterhin wurden signifikante Verminderungen der Gesamtzahl an abgelegten Eiern und der Eischlupfquote festgestellt.

Mites associated with abandoned fig trees in Egypt were observed during a 2-year study. This study included species diversity and seasonal fluctuations as well as some biological aspects of common eriophyoid species. Three phytophagous species consisted of the fig bud mite Aceria ficus (Cotte), the fig leaf mite Rhyncaphytoptus ficifoliae Keifer and the twospotted spider mite Tetranychus urticae Koch, representing a basic trophic level, were fed upon by three of predacious mites (Pronematus ubiquitus (McGregor), Amblyseius swirskii Athias-Henriot, Agistemus exsertus Gonzalez). Population abundance of the injurious mites were affected by the prevailing climatic conditions, action of predators and leaf age. A control measure of one summer pesticide (abamectin) application throughout the year seemed to be the most successful management of harmful mites. Life table parameters showed that the population of A. ficus multiplied 28.52 times in a generation time of 17.90 days, while R. ficifoliae population increasod 16.50 times in a generation time of 14.61 days. Field and laboratory studies indicated that the viviparity is a typical character in the reproduction of R. ficifoliae.

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The predacious mites Amblyseius gossipi El-Badry and A. swirskii Athias-Henroit developed, survived and reproduced successfully on several artificial diets. The best diet consisted of 1 g yeast, 1 g milk, 30 mg cystine, 30 mg proline, 30 mg arginine, 20 mg sucrose, 50 mg glucose, 30 mg streptomycin sulphate and droplets of sorbic acid. Mean eggs/female/day by the two predators was 0.54 and 030 when reared on the best diet compared to 1.21 and 0.40 when fed on a natural diet, respectively. Female longevity of A. swirskiiv/as 84 3 days, nearly twice as long as that on a natural diet Eggs showed no abnormalities; larvae fed on diets had normal development, and adults were comparable hi size to individuals reared on a natural diet. Resuml-Les acariens a predation, Amblyseius gossipi El Badry et A. swirskii Athias-Henroit etaient capables de se developper, survivre et se reproduire avec succes sur plusieurs milieux artificiels. Un milieu artlficiel compose de levure, lait, acides amlne et sucres a indiuit une oviposition soutenue et fourni un alimentation suffesante pour les predateurs. Le taux moyen d'oviposition des femelles etait d'environ la moitie et les 3/4 du taux complet chez les deux predateurs respectivement quand lls etaient testes sur milieu naturel. La longevity des femelles deA. swirskii etait a peu pres deux fois aussi longue que sur milieu naturel. Les oeufs obtenus des essais d'oviposition ne montraient aucune anotmalete. Les larves alimentees sur milieux artificiels avaient un developpement normal. Les adultes etaient semblables en taille aux indlvidus eleves sur milieux naturels.