Edamame, a specialty food-grade soybean popular among health-conscious
consumers, is growing in popularity worldwide. Despite a well-developed
soybean industry, most edamame consumed in the United States is imported
from Asia. Considerable interest exists in growing edamame domestically;
however, weed interference is a major problem, and until recently, only a
single herbicide was registered for use on the crop. The objectives of this
work were (1) to compare effectiveness of weed management treatments that
utilize herbicides currently registered for use on edamame or that may be
registered in the near future, (2) to determine the significance of edamame
cultivar on performance of these treatments, and (3) to identify potential
relationships between the crop and weed. Ten different weed management
treatments were tested in three edamame cultivars over a 3-yr period. All
weed management treatments increased marketable pod yield relative to the
nontreated control, but only treatments with saflufenacil or
S-metolachlor combinations were comparable to the
hand-weeded weed-free treatment. Of the treatments studied,
S-metolachlor followed by imazamox was among the
greatest yielding, had the least weed density and biomass, and did not
reduce crop population density. Also, cultivars differed in their
weed-suppressive ability. Path analysis indicated certain relationships were
consistent across cultivars, such as weed population density having a direct
negative association with crop biomass; however, other edamame–weed
interactions were not identical across cultivars. Although more improvements
are needed, the vegetable industry is beginning to have nascent weed
management options in edamame, which will likely reduce reliance on hand
weeding and result in crop-production costs that are more competitive in the
global market.