Bicyclopyrone and mesotrione are a HPPD-inhibiting herbicide (Group 27) registered for use in corn. Mesotrione is sold alone or in premixture with other herbicides; bicyclopyrone is sold only in premixtures. There is limited data available on the response of other crops planted into fields where these herbicides were applied. Greenhouse and field experiments were conducted to evaluate alfalfa, cucumber, black and kidney bean, and sugarbeet response to bicyclopyrone and mesotrione. In the greenhouse, cucumber, black bean, kidney bean, and sugarbeet were more sensitive to mesotrione compared with bicyclopyrone. Sugarbeet was the most sensitive to both bicyclopyrone and mesotrione followed by alfalfa. Cucumbers were the most tolerant to bicyclopyrone and mesotrione followed by kidney bean and black bean. In field research, bicyclopyrone at 50 and 100 g ha-1 (1 and 2X rate), and mesotrione at 210 g ha-1 were applied in early June to V4 corn at two locations in 2015 and 2016. The following spring, alfalfa and sugarbeet were planted in mid-April and cucumber and dry edible bean in early-June and crop response was measured. In 2016, injury in all crops was less than 20%, regardless of herbicide treatment at either location. In 2017 at East Lansing, sugarbeet was severely injured and did not survive where mesotrione was applied the previous year. Sugarbeet and kidney bean injury was 15 and 5%, respectively from the 2X rate of bicyclopyrone. Neither mesotrione or bicyclopyrone affected crop growth or yield at Richville in 2017. Soil pH was 6.0 and soil organic matter was 4.2 to 4.5% at East Lansing and soil pH was 7.8 and soil organic matter 2.6% at Richville. While there were differences in soils at the two locations, rainfall within the first 30 days following application contributed to differences in herbicide carryover. At East Lansing, rainfall was 20.5 and 2.8 cm within the first 30 days following application in 2015 and 2016, respectively, contributing to more herbicide carryover in the 2017 growing season than in the 2016 growing season. Rainfall at Richville had a 60% reduction in precipitation within the first 30 days however, no herbicide carryover was experienced. From this research it appears that alfalfa, dry bean or cucumber can be planted the year following mesotrione or bicyclopyrone application. However, sugarbeet should not be planted the year following applications of mesotrione or bicyclopyrone.
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