Techniques for Monitoring Cranberry Tipworm (Diptera: Cecidomyiidae) in Rabbiteye and Southern Highbush Blueberries

Abstract

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.

Evaluation of Emergence Traps for Monitoring Blueberry Gall Midge (Diptera: Cecidomyiidae) Adults and Within Field Distribution of Midge Infestation

“…D. oxycoccana larvae feed in developing ßower and leaf buds. In susceptible cultivars, Ͼ80 Ð90% of ßower buds can be destroyed, reducing potential fruit yield (Lyrene and Payne 1992, Sampson et al 2002, Sarzynski and Liburd 2003. Production of rabbiteye blueberries in Florida has been jeopardized due to heavy infestations (Sampson et al 2002).…”

“…D. oxycoccana adults are difÞcult to detect due to their small size (2Ð3 mm). Sticky traps have been used in some plantings to catch adult midges but have proven ineffective (Sarzynski and Liburd 2003). Furthermore, key morphological features can be damaged or obscured by the trapÕs sticky surface, making subsequent identiÞcation difÞcult (Sarzynski and Liburd 2003).…”

“…Sticky traps have been used in some plantings to catch adult midges but have proven ineffective (Sarzynski and Liburd 2003). Furthermore, key morphological features can be damaged or obscured by the trapÕs sticky surface, making subsequent identiÞcation difÞcult (Sarzynski and Liburd 2003). Sarzynski and Liburd (2003) investigated methods for detecting D. oxycoccana and found an emergence technique and bud dissections were useful for monitoring populations in the Þeld.…”

“…Furthermore, key morphological features can be damaged or obscured by the trapÕs sticky surface, making subsequent identiÞcation difÞcult (Sarzynski and Liburd 2003). Sarzynski and Liburd (2003) investigated methods for detecting D. oxycoccana and found an emergence technique and bud dissections were useful for monitoring populations in the Þeld. The emergence technique involved removing ßower buds from blueberry bushes, holding them in a growth chamber for 10 Ð14 d, and counting larvae or adults as they emerge.…”

“…Larvae begin emerging from buds within hours of being collected, but buds need to be held for a minimum of 10 d to obtain accurate counts of population density (unpublished data). Although bud dissection is a good technique for detecting eggs (Sarzynski and Liburd 2003), it is time-consuming, requires visual aid, and is not practical for growers (Finn 2003).…”