Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 30, 2011
Publication Date: January 12, 2012
Citation: Steffan, S.A., Singleton, M., Sojka, J., Zalapa, J.E., Harbut, R. 2012. Early-season flooding for insect pest control. Wisconsin Cranberry School 2012 Proceedings. 20:24-28. Technical Abstract: In Wisconsin, there is much interest in the spring flood as a means to not only reduce pest populations, but also to facilitate marsh sanitation and provide frost protection. 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. In parallel, greenhouse trials were initiated to investigate the submergence tolerances of these three cranberry varieties, under two temperature and three submergence duration regimes. To-date, it appears that cranberry plants in the field were largely unaffected by the flooding, although development of uprights in flooded beds may have been slightly delayed. Populations of black-headed fireworm (Rhopobota naevena) and cranberry fruitworm (Acrobasis vaccinii) appear to have been suppressed by the flooding, but again, the data are preliminary. Most growers sprayed insecticides on unflooded beds, effectively rendering pest populations similar between flooded and unflooded beds, and suggesting that the flood served as a replacement for an insecticide application. Collections of detritus floating atop the floodwaters were examined for arthropod fauna, and these samples yielded many noctuids, tortricids, and scarabs. From greenhouse trials, data to-date suggests that cranberry plants can endure prolonged submergence (up to 4 days) in either warm or cold water.