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Effect of hexazinone on species distributions and weed competition in lowbush blueberry fields in Maine
Abstract
Lowbush blueberries (Vaccinium angustifolium Aiton and V. myrtilloides Michaux) are produced on native or wild stands in Maine and Eastern Canada. The use of the herbicide hexazinone has caused changes in the weed populations in lowbush blueberry fields. To determine the effect of hexazinone on these species and on the growth and productivity of lowbush blueberries in commercial fields in Maine; blueberry and weed population cover, frequency, and blueberry plant stand and yield were sampled on two fields over four years. Cover and frequency of all species were compared to an earlier survey on 14 fields which had been treated once or twice with hexazinone. Blueberry plant stand was compared among the treated fields. Hexazinone-treated fields had a decline in the cover and frequency of a number of weed species and a corresponding increase in blueberry growth and yield. Open ground, bunchberry (Cornus canadensis L.) and dogbane (Apocynum androsaemifolium L.) increased in cover and frequency with hexazinone treatment. Replacement series experiments to assess competitive effects of bunchberry were established on native stands of blueberries in 1986 and 1987. Quadrats were established on prune and crop fields at cover ratios, where c = crop or blueberry and w = weed or bunchberry of 100c/0w, 75c/25w, 50c/50w, 25c/75w, 0c/100w. Dormant blueberry and bunchberry plugs from prune fields were grown in the above proportions in the greenhouse in the summer of 1987. In the field study, relative yields and regression of individual vs associate yield indicates that blueberry and bunchberry growth are equivalent. Blueberry fruit number and yield decreased with increasing bunchberry density. In the greenhouse study, relative yield, regression of individual versus associate yield, and leaf area index of blueberry and bunchberry indicated that blueberry grew as well or better in mixtures than in prune stands. Replacement series experiments indicated that blueberries are competitive with bunchberry but open areas among clones in native fields allow faster growing bunchberry to spread without competition. Two field experiments indicated that imidazoline compounds did not provide selective control of bunchberry but sulfonyl urea compounds merit further research for bunchberry suppression.
Subject Area
Agronomy|Ecology
Recommended Citation
Yarborough, David E, "Effect of hexazinone on species distributions and weed competition in lowbush blueberry fields in Maine" (1991). Doctoral Dissertations Available from Proquest. AAI9120960.
https://scholarworks.umass.edu/dissertations/AAI9120960