The influence of agronomical and chemical weed control on weeds of corn

Weeds in sweet corn reduce the yield and are economically more harmful than other pests. The aim of this study was to evaluate the effects of mechanical weed control and efficacy of pre-and postemergence applied herbicides in sweet corn, and their influence on weed control expressed by various indices, corncob yield and net return. Field studies were carried out with preemergence thiencarbazone-methyl + isoxaflutole (at 29.7 + 74.3 g · ha –1 ), postemergence S-metolachlor + terbuthylazine (937.5 + 562.5 g · ha –1 ), mesotrione + ter-buthylazine (100 + 652 g · ha –1 ), terbuthylazine + mesotrione + S-metolachlor (656.3 + + 131.3 + 1093.8 g · ha –1 ), weed free (WF, hand weeding), and mechanical weeding (MW, hoeing) to assess weed control, corncob yield and net return. Variability in potential yield losses was observed between years due to weather conditions at the level of 30 to even 93%. Hand weeding was the most effective, but it is expensive and needs is labour consuming, unlike mechanical weeding which was the cheapest but simultaneously the least effective. Among pre-and postemergence applied herbicides, a mixture of terbuthylazine + mesotri-one + S-metolachlor was the most efficacious weed control treatment. It gave high corncob yield and economic net return.