Herbicide options for glyphosate-resistant kochia (Bassia scoparia) management in the Great Plains

Gustavo M Sbatella,Phil Westra,Albert T Adjesiwor,Phillip W Stahlman,Robert G Wilson,Andrew R Kniss,Michael Moechnig

doi:10.1017/wet.2019.48

Abstract

AbstractKochia is one of the most problematic weeds in the United States. Field studies were conducted in five states (Wyoming, Colorado, Kansas, Nebraska, and South Dakota) over 2 yr (2010 and 2011) to evaluate kochia control with selected herbicides registered in five common crop scenarios: winter wheat, fallow, corn, soybean, and sugar beet to provide insight for diversifying kochia management in crop rotations. Kochia control varied by experimental site such that more variation in kochia control and biomass production was explained by experimental site than herbicide choice within a crop. Kochia control with herbicides currently labeled for use in sugar beet averaged 32% across locations. Kochia control was greatest and most consistent from corn herbicide programs (99%), followed by soybean (96%) and fallow (97%) herbicide programs. Kochia control from wheat herbicide programs was 93%. With respect to the availability of effective herbicide options, glyphosate-resistant kochia control was easiest in corn, soybean, and fallow, followed by wheat; and difficult to manage with herbicides in sugar beet.

Highlights

Kochia is an invasive annual forb native to Asia, introduced into the United States at the end of the 1800s as an ornamental from Europe (Friesen et al 2009; Whitson et al 2000)
The chosen herbicide programs were a representative sample of possible herbicide combinations that would provide the best kochia control within each crop of interest (Table 1)
Experimental site explained more variation in control estimates compared with herbicide treatment within the crop scenario; the crop scenario for which herbicide treatments were registered explained the greatest amount of kochia control variance (Table 2)

Summary

Introduction

Kochia is an invasive annual forb native to Asia, introduced into the United States at the end of the 1800s as an ornamental from Europe (Friesen et al 2009; Whitson et al 2000). Yield loss from kochia competition has been documented in many crops, including oats (Avena sativa L.), wheat, sugar beet, sunflower (Helianthus annuus L.), and alfalfa (Calpouzos et al 1980; Friesen et al 1993; Lewis and Gulden 2014; Manthey et al 1996; Mesbah et al 1994). In addition to these competitive traits, kochia is adapted to a variety of common agricultural practices. Effective kochia management is a priority in most crop production systems

Objectives

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Results