|Bergh, J - VIRGINIA TECH|
Submitted to: Annual Cumberland Shenandoah Fruit Workers Conference
Publication Type: Proceedings
Publication Acceptance Date: January 30, 2002
Publication Date: N/A
Technical Abstract: The dogwood borer (DWB), Synanthedon scitula Harris, is becoming an increasingly important economic pest in commercial apple orchards. This is due in large part to increased plantings of apple trees on size-controlling rootstocks that promote the formation of burrknots near the graft union and elsewhere on the scion. Furthermore, review of chemical tolerances as dictated by the Food Quality Protection Act (FQPA) has made continued availability of the most effective insecticide for controlling dogwood borer (chlorpyrifos) uncertain. At the outset of the 2001 field season, our primary objectives were: to compare the response of DWB to young apple trees with and without burrknot tissue; to examine the response of DWB to a combination of visual and olfactory stimuli; to develop the relationship between the capture of males in pheromone traps and the abundance of pupal cases; and, to measure the sex ratio of DWB over the season based on pupal case morphology. Unexpected negative results from our pheromone trapping during the early part of the 2001 flight season prompted us to include a preliminary comparison of the effectiveness of pheromone lures, and to begin examining phenology and voltinism of DWB in apple based on temporal changes in the frequency distribution of larval instars collected from apple burrknot tissue.