Weed Control J 2022; 21: e202200766

Research Article

Horseweed chemical control in pre-plant burndown in soybean

DOI: 10.7824/wcj.2022;21:00766

Abstract

Background

Soybean is one of the most important crops planted in Brazil. The management of weeds becomes necessary, in this case the horseweed (Conyza spp.), because the lack of control is responsible for a significant reduction in production. No-tillage in the main straw system used in soybean crops and with the prohibition of the herbicide paraquat, used in the pre-planting of the crop in Rio Grande do Sul, efficient alternatives to this management were evaluated.

Objective

The objective of this work was to identify efficient alternatives to the sequential pre-planting management of soybeans to replace paraquat.

Methods

The experiment was established with desiccation of the area with glyphosate + 2,4-D and sequential applications of paraquat; glufosinate alone and in combination with chlorimuron; flumioxazin and diclosulam; diquat alone and in association with chlorimuron; flumioxazin and diclosulam. In addition to the control, the percentage control of horseweed plants and reinfestation were evaluated by counting the emerged plants in 1m ² with evaluations at 7, 14, 21, 28 and 35 DAT. The percentage of vegetation cover was also evaluated using the Canopeo application at 21 and 35 days DAT.

Results

From this, it was found that the mixtures of glufosinate products with chlorimuron, flumioxazin and diclosulam and diquat with chlorimuron, flumioxazin and diclosulam showed satisfactory control and compatible with the efficiency of paraquat.

Conclusions

It was identified that paraquat can be adequately substituted in the pre-seeding sequential management for horseweed control by glufosinate or diquat applied in association with chlorimuron, flumioxazin or diclosulan.