Techniques for monitoring cranberry tipworm (Diptera: Cecidomyiidae) in rabbiteye and southern highbush blueberries

Several monitoring techniques were evaluated for their effectiveness, based on the highest mean captures of cranberry tipworm, Dasineura oxycoccana (Johnson), in detecting D. oxycoccana in rabbiteye, Vaccinium ashei Reade, and southern highbush, V. corymbosum L. x V. darrowi Camp, blueberry plantings. There were no significant differences in captures of D. oxycoccana adults on unbaited sticky board traps, regardless of color (yellow, white, green, or blue). In a separate experiment, three monitoring techniques, yellow unbaited sticky boards, larval/adult emergence from infested buds, and bud dissection, were evaluated for detecting D. oxycoccana, eggs, larvae, and adults. In total, four bud types were examined, including rabbiteye floral, rabbiteye leaf, southern highbush floral, and southern highbush leaf. The emergence monitoring technique detected significantly more D. oxycoccana adults than the other techniques evaluated. Emergence and dissection techniques performed equally well for detecting D. oxycoccana larvae. Dissection was the only technique capable of detecting D. oxycoccana eggs. Overall, the highest numbers of D. oxycoccana eggs were detected in southern highbush leaf buds. However, larval infestation was lower for southern highbush leaf buds compared with other bud types sampled. Hypotheses to explain this phenomenon are discussed. The fewest number of eggs was recorded for southern highbush flower buds, potentially because these buds develop before peak emergence of D. oxycoccana. Managing D. oxycoccana in infested plantings can be improved by incorporating monitoring techniques, specifically bud dissection to search for eggs, that will aid growers in making timely insecticide applications.