Hophornbeam Copperleaf (Acalypha ostryifolia) Biology and Control

Abstract

Little is known about the biology and control of hophornbeam copperleaf, a weed of increasing importance in the Midwest. More than 2 wk of cold stratification and a 0.2% KNO3solution increased germination of hophornbeam copperleaf. Germination at constant 30 C was 47% and alternating 30/20 C was 65%. Scarification did not increase hophornbeam copperleaf germination. Within the first 600 growing degree days after soybean planting, plant height, leaf area, and dry matter accumulation of hophornbeam copperleaf grown in soybean and alone were similar. Subsequently, leaf area and dry matter accumulation of hophornbeam copperleaf grown alone were greater than of those grown in soybean. In contrast, plant height of hophornbeam copperleaf grown in soybean was greater than when grown alone. Hophornbeam copperleaf grown alone produced up to 12 510 seeds/plant, whereas hophornbeam copperleaf grown with soybean produced 980 seeds/plant. Of 13 postemergent herbicides evaluated on hophornbeam copperleaf in soybean, only lactofen, acifluorfen, and fomesafen controlled 80% or more. Lactofen at 210 g ai/ha consistently controlled more than 95% of the hophornbeam copperleaf.