MONITORING BLACK SCALE IN CALIFORNIA OLIVE ORCHARDS

Black scale, Saissetia oleae (Olivier) (Homoptera: Coccidae), is an explosive and unpredictable pest in California olive orchards. A four year study found that cultural practices (e.g. irrigation) and summer weather greatly influence scale biology. To improve control, a monitoring program is being designed based on cultural practices, adult scale density, and summer temperatures. Regression analysis of mean-variance estimates showed that of cultural practices studied, canopy structure had the most influence on scale distribution and mortality. Scale distribution is highly aggregated with most scale, honeydew, and mold found in the lower and inner canopy sections. Constant precision sampling was determined for each of three canopy types: open, two-microclimatic, and closed.