CRANBERRY GENETIC IMPROVEMENT AND INSECT PEST MANAGEMENT
Location: Vegetable Crops Research Unit
Title: Spotted Wing Drosophila, Sparganothis phenology and a new look at the BugFloods
Submitted to: Wisconsin Cranberry School
Publication Type: Proceedings
Publication Acceptance Date: January 14, 2013
Publication Date: January 22, 2013
Citation: Steffan, S.A., Lee, J.C., Deutsch, A., Singleton, M., Rodriguez-Saona, C., Zalapa, J.E. 2013. Spotted Wing Drosophila, Sparganothis phenology and a new look at the BugFloods. Wisconsin Cranberry School. 21:1-6.
Drosophila suzukii, commonly known as spotted wing drosophila (SWD), does not readily oviposit in cranberries. Following multiple replicated trials using ripe, under-ripe, and over-ripe organic Wisconsin cranberries, SWD females would not (or could not) insert eggs into under-ripe or ripe cranberries. This suggests that healthy, current-year fruit should be safe from attack. Conversely, last-year’s decaying bounty of unharvested cranberries may be vulnerable. SWD populations will likely be found each spring and summer in fruit-growing regions, but the risk to cranberry production seems minimal.
A large-scale field study was undertaken in 2011 to examine how a 30-40 hour spring flood (late May) would affect key insect populations, as well as the cranberry plant. A total of 46 beds were included in the study (23 pairs of flooded/unflooded beds across 11 marshes in central Wisconsin), focusing on ‘Stevens,’ ‘Ben Lear,’ and ‘GH1’ cranberry varieties. Collections of detritus floating atop the floodwaters were examined for arthropod fauna, and these samples yielded many noctuids, tortricids, and scarabs. Arthropod counts suggest that tens of thousands of individuals per-acre are commonly removed during the “trash floods.”