Environmental effects on efficacy of herbicides for postemergence goosegrass (Eleusine indica) control

Avat Shekoofa,Matthew T Elmore,Jose J Vargas,Daniel P Tuck,James T Brosnan

doi:10.1038/s41598-020-77570-5

Abstract

Experiments were conducted to understand environmental effects on efficacy of herbicides used to control goosegrass (Eleusine indica L. Gaertn.). Herbicides were applied to goosegrass maintained at soil moisture contents (VMC) of < 12%, 12 to 20%, or > 20%. Herbicides included fenoxaprop-p-ethyl (140 g ha−1), topramezone (25 g ha−1), foramsulfuron (44 g ha−1), 2,4-D + dicamba + MCPP + carfentrazone (860 + 80 + 270 + 28 g ha−1), and thiencarbazone-methyl + foramsulfuron + halosulfuron-methyl (22 + 45 + 69 g ha−1). Goosegrass control increased as VMC increased. Vapor pressure deficit (VPD) and air temperature were manipulated to determine effects of evaporative demand on foramsulfuron. Effects of soil drying were also studied following foramsulfuron application. Reductions in transpiration rate (TR) and leaf area were greatest with foramsulfuron applications to goosegrass in silt-loam under high evaporative demand (3 kPa VPD, 38 °C). Foramsulfuron had no effect on goosegrass in silica-sand regardless of evaporative demand. TR dropped to 0.2 mmh−1 within eight days after application to goosegrass in silt-loam compared to 18 days in silica-sand. Overall, foramsulfuron efficacy on goosegrass was maximized under conditions of high soil moisture and evaporative demand, and may be reduced in sandy soils that hold less water.

Highlights

Experiments were conducted to understand environmental effects on efficacy of herbicides used to control goosegrass
A significant year-by-soil moisture-by-herbicide interaction was detected in goosegrass control data (P < 0.0001); data from each year were analyzed and are presented separately
A significant soil moisture-by-herbicide interaction was detected in goosegrass control data collected in 2018

Summary

Introduction

Experiments were conducted to understand environmental effects on efficacy of herbicides used to control goosegrass Dortenzio and N orris[12] reported less control of barnyardgrass [Echinochloa crus-galli (L.) Beauv] and wild oat (Avena fatua L.) with the ACCase-inhibiting herbicide diclofop-methyl (HRAC Group #1) applied to plants maintained at 10% soil moisture compared to 30%. Reynolds et al.[15] reported reduced basipetal translocation of 14C-fluazifop-butyl, 14C-sethoxydim, 14C-haloxyfop-methyl, and 14C-quizalofop-ethyl applied to grain sorghum [Sorghum bicolor (L.) Moench] under moisture stress (leaf water potential − 680 kPa). Reduced control of barnyardgrass was reported with applications of diclofop-methyl to plants maintained at low water potential as w ell[16]. When studying wild accessions of goosegrass and plantain signalgrass (Urochloa plantaginea) from Brazil, efficacy of ACCase-inhibiting herbicides was reduced with applications made to plants under moisture s tress[17,18]. Increased expression of superoxide dismutase and catalase under drought conditions have been linked with reduced phytotoxicity following fenoxaprop-ethyl treatment to wild oat[19]

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Conclusion