K.V. McCully1, G. Chiasson2, E. Theriault3, M.J. Melanson1 and G.L. Graham1
Partner: New Brunswick Wild Bluberry Growers Association
Abstract: A trial was established in the fall of 2004 in Val Doucet, NB to evaluate the effect of a fall application of dicamba, 2,4-D ester plus dicamba, triclopyr, glyphosate or glyphosate plus Sylgard on weed control of lambkill (Kalmia angustifolia L.) and rhodora (Rhododendron canadense L.) followed by mowing or burning for vegetation management. In addition to crop yield, visual observations on crop injury and weed control were collected. Vegetation management practices after herbicide application did not have an effect on weed control efficacy or crop tolerance in this trial. All herbicides tested caused significant blueberry injury early in the season, with the triclopyr, glyphosate and glyphosate plus Sylgard recovering to commercially acceptable levels by the end of the test period. Dicamba injury was severe and crop yield was reduced. Only dicamba offered extended control of lambkill, with the remaining treatments showing a level of suppression. Dicamba mixtures were also successful in controlling rhodora, with greater than 80% control over all evaluation timings. Triclopyr offered moderate suppression and the glyphosate mixes demonstrated limited to no activity against this weed species. As these are major weed problems in blueberry production, producers may accept a higher level of blueberry damage if the weed problem can be controlled. The damage shown by dicamba mixtures would not be acceptable within commercial production although a reduction in yield may be acceptable within the establishment years, especially if rhodora could be effectively controlled. Further testing is required to verify the results found and the examination of innovative herbicide combinations should also be pursued.
1 NB Department of Agriculture and Aquaculture, Crop Development Branch, P.O. Box 6000, Fredericton, NB, E3B
2 Department of Agriculture and Aquaculture, Regional Agri-Business Development, 1425 King Avenue, Bathurst, NB, E2A 1S7
3NB Department of Agriculture and Aquaculture, Regional Agri-Business Development, P.O. Box 3058, Tracadie-Sheila, NB, E1X 1G5