Farmer Experience with Weed Resistance to Herbicides in Cotton Production
Zhou, X., J. A. Larson, D. M. Lambert, R. K. Roberts, B. C. English, K. J. Bryant, A. K. Mishra, L. L. Falconer, R. J. Hogan, Jr., J. L. Johnson, and J. M. Reeves.  2015.  AgBioForum, 18,1: 114-125.

Abstract:
A mail survey of 2,498 cotton farmers in 13 southern cotton producing states was conducted in 2012 to assess the temporal and geographic extent of weed resistance to herbicides in cotton production, appraise changes in cotton farmer production practices due to weed resistance to herbicides and the effectiveness of those practices, and evaluate how changes in production practices to manage weed resistance have influenced cotton weed control costs. Over two-thirds of the farmers surveyed reported herbicide resistant weeds on their farms. Pigweed was the dominant weed problem, making up 61% of these responses; horseweed about 25%. Newly observed infestations of pigweed and horseweed peaked in 2008-2009 and have declined thereafter. Farmers relied extensively on labor intensive and mechanical/chemical practices to control resistant weeds. The proportion of farmers in the sample who indicated they had total weed control costs of $50 or more per acre nearly doubled with the emergence of herbicide resistant weeds on their farm.