The phenology of Aonidiella aurantii (Maskell) was studied on mature 'Navel' orange trees at Lind cove, Tulare County, Calif. Scale populations were monitored using leaf and twig samples and synthetic sex pheromone traps. The lower developmental threshold (t = 11.6°C) and the thermal constant (K = 616.4 °D) for total development (crawler to crawler) were calculated from existing reports in the literature. Degree-day (°D) accumulations were derived from within-grove hygrothermograph data using t = 11.7°C. The F1 and F3 generations showed well-defined progressive peaks in all developmental stages but the F2 generation was anomalous. Coincidental peaks in adult virgin female and adult male numbers captured with pheromone traps during the F1 and F2 generations and absence of peaks in these stages during the F2 generation indicated that male flight patterns reflected development in scale generations. Stage-specific durations and total developmental time (T°D), as described by accumulated °D, were similar for the F1 and F2 generations and T°D (F1 605.6 °D; F3, 572.8 °D) closely approximated K. Degree-day accumulations between consecutive stage-specific peaks were more variable than °D accumulations between consecutive onsets of stage-specific increases but both measurements closely approximated K when averaged over three or more generations. These observations indicated that field populations of A. aurantii at Lindcove are well described by physiological time. The variability in adult male capture patterns commonly observed during midsummer in the San Joaquin Valley was partially explained by the absence of progressive peaks in female stages and the near absence of immature males during the F2 generation, but the causative factors were not determined.
Document Type: Research Article
Publication date: February 1, 1985
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.