http://worldcat.org/entity/work/id/22214004

Biology, spatial distribution, and control of Oligonychus Oligonychus ilicis McGregor Acarina: Tetranychidae on Ilex crenata 'Hetzii'

Studies were conducted to determine the temperature effects on the development and reproduction of the southern red mite, Oligonychus (Oligonychus) ilicis (McGregor) reared on holly, Ilex crenata 'Hetzii, ' to ascertain the mites' spatial distribution on field grown I. crenata, and to evaluate selected acaricides for residual control of 0. (0.) ilicis . Southern red mites completed development through all stages under constant temperatures ranging from 15.5 to 35 °C. In general, developmental times of all stages and adult longevity decreased as temperatures increased. Males developed more rapidly than females at all temperatures except 2 6.5°C. The developmental curves for all stages were cubic. Mortality curves for males and females dropped more abruptly as temperature increased. The survival rate of 0. (0.) ilicis was greatest for eggs, and the highest mortality occurred in the larval stage. The net reproductive rate was highest (7.0961) at 26.5°C. The mean generation time was shortest (2.5695) at 35° and longest (7.3119) at 21°C. The intrinsic rate of natural increase was greatest (0.4694) at 26.5°C. The number of degree days required for the development of each immature stage at 6 different temperatures indicated that the egg stage required the greatest amount of heat. Southern red mites were found predominantly on the under surface of I_. crenata. The mean number of mites in the upper portion of the plants differed significantly at the 1% level from the means for the lower and middle heights. Means for eggs did not differ with regard to height. Significantly more eggs and mites were located in the inner zone of the plants. More eggs and mites were found in the north and south quadrants than in the east and west quadrants. The optimum sampling location on I_. crenata appeared to be in the inner zone and at the upper height in either the north or south quadrants. Hexakis (H), propargite (P), dicofol (D), and naled (N) and combinations of these 4 acaricides were evaluated for control of 0. (0.) ilicis on field grown holly. Hexakis provided the best control after three weeks of the compounds sprayed singly. Combinations of compounds offering equally good residual action were H+p, H+D, H+P+D, H+P, N, P+D+N, and H+P+D+N.

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