Using Phenology to Time Insecticide Applications for Control of California Red Scale (Homoptera: Diaspididae) on Citrus

Abstract

The relative efficiency of different timings of chlorpyrifos applications for controlling California red scale, Aonidiella aurantii (Maskell), was evaluated in 3 yr of field tests (1985-1987). The timing of applications was made in relation to male flight phenology and focused around the second male flight period. Optimal timing for chlorpyrifos application in 1985 and 1987 occurred 2-4 wk after the peak of the second male flight period. In 1986, the optimal timing period was longer in duration and lasted over 4 wk. Applications made close to the beginning of the second flight period or several weeks after the lowest male catches between the second and third flight periods resulted in relatively poor control. The third year's experiment was expanded to include earlier application times and suggested another optimal time for California red scale control during the second half of the first male flight period. Data from traps used to monitor crawlers in the third year suggested that optimal timing coincided with sharp increases in crawler production at the beginning of each generation.