Herbicide selectivity and efficacy in weed control in canola production system

Abstract

Canola is an essential oilseed in global agriculture, contributing to the economic, social, and environmental sectors due to its versatility and nutritional value. Despite the notable growth of canola in Brazil, weed management poses a challenge due to the scarcity of registered selective herbicides and the prohibition of transgenics, resulting in productivity losses. Therefore, it is crucial to develop innovative technologies and generate knowledge to guide effective weed management and facilitate the expansion of canola in the country. Field studies during the 2022/2023 growing season evaluated the selectivity of herbicides in canola production and their effectiveness in weed control. The pre-emergent treatments were: clomazone, s-metolachlor, clomazone + s-metolachlor, and no pre-emergent herbicide; and the post-emergent treatments were: quinclorac, dicamba, quinclorac + dicamba, and no post-emergent herbicide, in addition to a weed-free control. Although clomazone, quinc lorac, and dicamba are not registered for use in canola in Brazil, they showed promising results by significantly reducing weed interference without negatively impacting oil and protein contents or yield components. Combinations S-metolachlor + clomazone and quinclorac + dicamba, provided the best outcomes in both weed control and grain productivity, with yields reaching 2053.29 kg ha⁻¹ in Lavras. These findings suggest that the tested herbicides have potential for selective use in canola production, paving the way for further studies aimed at their registration and incorporation into production systems.