Integrating Reduced Herbicide Use with Mechanical Weeding in Corn (Zea mays)

Concern about the effects of pesticides on the environment and the desire to reduce purchased inputs are stimuli to reduce herbicide use. Field research was conducted at two locations for two growing seasons to identify integrated weed management practices in corn that are effective and economical. Weed control treatments included PRE application of a herbicide mixture of 1.8 kg ai ha −1 of atrazine plus 2.2 kg ai ha −1 of metolachlor alone, this mixture broadcast or band-applied at a reduced rate in combination with mechanical weeding, and mechanical weeding alone. Weed control, corn yield, and economic returns were generally higher in treatments combining herbicides and mechanical weeding than those using only mechanical measures. Without herbicides, timeliness of rotary hoeing was critical. Herbicide use can be reduced 50 to 75% in integrated systems with minimal risk of yield loss due to uncontrolled weeds.