Potential wheat yield loss due to weeds in the United States and Canada

Michael L Flessner,Breanne Tidemann,Nader Soltani,J Anita Dille,Misha R Manuchehri,Peter H Sikkema,Wesley J Everman,Ian C Burke,Mark J Vangessel

doi:10.1017/wet.2021.78

Abstract

AbstractYield losses due to weeds are a major threat to wheat production and economic well-being of farmers in the United States and Canada. The objective of this Weed Science Society of America (WSSA) Weed Loss Committee report is to provide estimates of wheat yield and economic losses due to weeds. Weed scientists provided both weedy (best management practices but no weed control practices) and weed-free (best management practices providing >90% weed control) average yield from replicated research trials in both winter and spring wheat from 2007 to 2017. Winter wheat yield loss estimates ranged from 2.9% to 34.4%, with a weighted average (by production) of 25.6% for the United States, 2.9% for Canada, and 23.4% combined. Based on these yield loss estimates and total production, the potential winter wheat loss due to weeds is 10.5, 0.09, and 10.5 billion kg with a potential loss in value of US$2.19, US$0.19, and US$2.19 billion for the United States, Canada, and combined, respectively. Spring wheat yield loss estimates ranged from 7.9% to 47.0%, with a weighted average (by production) of 33.2% for the United States, 8.0% for Canada, and 19.5% combined. Based on this yield loss estimate and total production, the potential spring wheat loss is 4.8, 1.6, and 6.6 billion kg with a potential loss in value of US$1.14, US$0.37, and US$1.39 billion for the United States, Canada, and combined, respectively. Yield loss in this analysis is greater than some previous estimates, likely indicating an increasing threat from weeds. Climate is affecting yield loss in winter wheat in the Pacific Northwest, with percent yield loss being highest in wheat-fallow systems that receive less than 30 cm of annual precipitation. Continued investment in weed science research for wheat is critical for continued yield protection.

Highlights

Weeds are the most significant pest in wheat worldwide (Oerke 2006)
Bridges (1992) reported 1% to 20% wheat yield loss due to weeds across the United States using -current management; BMPs but no herbicides resulted in 3% to 60% wheat yield loss
Weedy yield was the average yield from the nontreated weedy plot, whereas weed-free yield was the average yield from an herbicide control plot with >90% control for each weed species

Summary

Introduction

Weeds are the most significant pest in wheat worldwide (Oerke 2006). Previous estimates of global wheat yield loss due to weeds were 9.8% (Cramer 1967) and 12.3% (Oerke et al 1994). In 2006, Oerke estimated the worldwide potential wheat loss to be 23.0% with a range of 18% to 29% and actual loss of 7.7% with a range of 3% to 13%. Chandler et al (1984) reported an estimated 9% to 20% wheat yield loss with an average of 13% across the United States and 5% to 15% wheat yield loss across Canada due to weeds. Bridges (1992) reported 1% to 20% wheat yield loss due to weeds across the United States using -current management (i.e., best management practices [BMPs] with herbicides); BMPs but no herbicides resulted in 3% to 60% wheat yield loss. In a summary of yield loss due to weeds in Canada, Swanton et al (1993) reported 5% to 15% wheat yield loss

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