Abstract

The raspberry beetle is a key insect contaminant of machine-harvested raspberries in Whatcom County, Washington State. Tolerances for this contaminant range from zero tolerance to moderate depending on the berry grade that is harvested. In Whatcom County, over 2,800 ha of red raspberry are grown and many of these acres are treated with a calendar-based application of diazinon to control raspberry beetle. Through co-operation with the Scottish Crop Research Institute, Washington State University has developed a monitoring technique to evaluate raspberry beetle levels in red raspberry fields. A white, non-ultraviolet reflective sticky trap is attached to the top support wire every 2040 rows, approximately 10 m from the perimeter of the fields. Traps should be monitored weekly, or at least once, before making a decision to apply a pesticide for treatment of raspberry beetle. Preliminary thresholds for raspberry beetle have been established for different processing grades, ranging from individually quick-frozen to juice quality, and these will aid growers in making wise decisions on the application of a pesticide. These thresholds may then be fine-tuned for each grower. During 2004, three growers opted to avoid applying a pesticide treatment to control raspberry beetle due to low numbers of adult beetles in the traps. Through increased use of this monitoring tool, growers will be able to determine their own acceptable thresholds appropriate for each processing grade with the expectation of reduced pesticide reliance.