Flooding to manage dodder (Cuscuta gronovii) and broad-leaved weed species in cranberry: An innovative use of a traditional strategy

Abstract

AbstractThe implementation of new uses for traditional cultural and pest management practices has been prompted by renewed interest in sustainable approaches for farming. The use of floods (for various durations) has been an inexpensive and historical cultural practice in cranberry (Vaccinium macrocarponAit.) horticulture. The onset of a serious economic crisis in the cranberry industry in 1999–2000 brought about an urgent need to find inexpensive methods of pest control that would allow growers to remain fiscally solvent. Initially, anecdotal evidence from several farms indicated that holding short-term spring floods suppressed dodder infestations. Based on these findings, a 2-year demonstration-style project was initiated in 2002 to determine the efficacy of short-term floods (24–48 h) for the management of dodder in cranberry in Massachusetts. The project was expanded to include evaluating a 10-day summer flood for control of broad-leaved weed species at one commercial cranberry farm. Species richness and diversity and percentage weed coverage were lower after the implementation of the 10-day flood period compared to pre-flood assessments. Weed species dead or not detected after the 10-day flood included ground nut, asters, narrow-leaved goldenrod, chokeberry and poison ivy. Comparison of paired sites (flooded and nonflooded bogs) indicated dodder stem dry weights were lower on flooded areas in three out of the seven locations in year 1. At two additional locations, the flooded bog had higher stem weights when paired with a historically low-infestation bog, which may have masked any dodder reduction from the flooding practice. In year 2, no differences in the number of germinated seedlings between any treatment pairs were noted. Data from a cranberry company representing 12% of the cranberry acreage in Massachusetts indicated a 65–89% reduction in pesticide use when short-term spring floods were implemented during 2001–2003 compared to the previous 3-year period. Short-term flooding may offer a sustainable option that can be integrated into the overall management plan for several problematic cranberry weed species, especially dodder. Additional research is warranted to further define the most effective environmental conditions needed and to validate the efficacy of short flooding events for effective cranberry weed management.