Economic threshold of smooth pigweed escaped from a herbicide program in roundup ready® soybean

Renan R Zandoná,Dirceu Agostinetto,João Gabriel S Göebel,Maicon F Schmitz,Adriana A Do Amarante,Geovana F Barbieri

doi:10.51694/advweedsci/2022;40:amarathus002

Abstract

Introduction A. hybridus interference in soybeans varies with population size and may be quantified by mathematical models that allow establishing the threshold levels. Objective Determine the interference of A. hybridus escaped from an herbicide program and with multiple resistance to EPSPs and ALS-inhibiting herbicides on soybean yield and its economic threshold (ET). Methods Two experiments were conducted in a randomized block design. The treatments consisted of populations of A. hybridus ranging from 0 to 41 plants m-2 (2018/19) and [...]

Highlights

A. hybridus interference in soybeans varies with population size and may be quantified by mathematical models that allow establishing the threshold levels
Yield losses due to competition with Amaranthus palmeri vary between 6 and 65% depending on time of emergence and population density (Berger et al, 2015)
Regarding the variable yield loss of grains plant-1, there was significance in the two years of test, and the rectangular hyperbola model was fitted this variable (Figure 3). To analyze this variable in 2019/20, it was necessary to set the value of the parameter a of the rectangular hyperbola at 100% (Figure 3b), as the model

Summary

Introduction

A. hybridus interference in soybeans varies with population size and may be quantified by mathematical models that allow establishing the threshold levels. The species of the genus Amaranthus are among the main weeds found in soybeanproducing regions in Brazil. They are characterized by rapid growth and initial development, intense production of viable seeds per plant, and uneven germination, resulting in emergence flows throughout the growth of agricultural crops (Horak, Loughin, 2000; Netto et al, 2016). The level of competition depends on species, population density, phenological stage, and time of weed coexistence with the crop (Vitorino et al, 2017). Yield losses due to competition with Amaranthus palmeri vary between 6 and 65% depending on time of emergence and population density (Berger et al, 2015). Amaranthus retroflexus in populations of up to 32 plants m-2 promote reductions of 81% in the productivity of common beans due to competition (Amini et al, 2014)

Objectives

Methods

Results