Populations of San Jose scale (SJS), Quadraspidiotus perniciosus (Comstock), adult males and crawlers were monitored with pheromone traps checked weekly and associated sticky tape traps monitored biweekly, respectively, in Kern County, CA commercial almond orchards in 1999 and 2000. Regression analysis was used to determine if abundance of SJS crawlers could be predicted from SJS males captured on pheromone traps. No significant relationship was indicated for any generation or for all SJS captured for the season in 1999. In 2000, a statistically significant relationship was indicated for the first generation and for all generations together. An additional orchard in 2000 was divided into eighteen 1.21 ha plots with different treatments applied. A statistically significant relationship was indicated for the first generation and second generation. These results suggest that relative densities of SJS crawlers on sticky tapes can be estimated using SJS male trap captures for the first generation, and that this approximation is appropriate for whole orchards or for subplots within orchards as small as 1.21 ha. In addition to SJS, its parasitoids Encarsia perniciosi (Tower) and Aphytis spp. were also monitored with pheromone traps in one of the orchards of the study. Blocks within the orchard were treated during winter dormancy with several insecticides, including oil alone, oil combined with the organophosphate diazinon at different dilution rates, and oil combined with the pyrethroid esfenvalerate. A completely randomized block design evaluated alternatives to the use of diazinon, which has been implicated in surface water contamination. Higher volume diazinon applications proved effective against SJS, as did esfenvalerate. The lower volume application of diazinon was generally less effective in controling the crawlers. All insecticide treatments were associated with a reduction of parasitoids, especially the application of esfenvalerate.
Species 1: Homoptera Diaspididae Quadraspidiotus perniciosus (San Jose scale)
Species 2: Hymenoptera Aphelinidae Encarsia perniciosi
Species 3: Hymenoptera Aphelinidae Aphytis
Keywords: dormant spray
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA