DISTRIBUTION OF PANONYCHUS-CITRI (MCGREGOR) AND EUSEIUS-TULARENSIS CONGDON ON CENTRAL CALIFORNIA ORANGE TREES WITH IMPLICATIONS FOR BINOMIAL SAMPLING
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Adults and active stages of the citrus red mite, Panonychus citri (McGregor) and active stages of the predatory mite Euseius tularensis Congdon were sampled in a central California orange grove for the period 1968-1976. In 1983, 10 groves were sampled for P. citri adult females. Analysis of variance showed no difference (P > 0.05) between sampling locations within a tree. Clumping pattern per leaf for each species and age class sampled were expressed as the relationship between proportion of leaves infested with mites, mean number of mites per leaf and variance of mites per leaf. The clumping patterns of both P. citri classes were fairly constant between years and between orchards and were more clumped than with E. tularensis. The relationship between proportion of leaves infested and mean number of mites per leaf was determined for both species and age classes and incorporated into a binomial sampling program. Binomial sequential sampling schemes were developed for P. citri using thresholds proposed in the literature. 1985.