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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #291249
Title: Glufosinate application timing and rate affect peanut yield

Author
item PROSTKO, ERIC - UNIVERSITY OF GEORGIA
item WEBSTER, THEODORE
item MARSHALL, MICHAEL - CLEMSON UNIVERSITY
item LEON, RAMON - UNIVERSITY OF FLORIDA
item GREY, TIMOTHY - UNIVERSITY OF GEORGIA
item FERRELL, JASON - UNIVERSITY OF FLORIDA
item DOTRAY, PETER - TEXAS TECH UNIVERSITY
item JORDAN, DAVID - NORTH CAROLINA STATE UNIVERSITY
item GRICHAR, W - TEXAS A&M AGRILIFE
item BRECKE, BARRY - UNIVERSITY OF FLORIDA

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2013
Publication Date: 9/1/2013
Citation: Prostko, E.P., Webster, T.M., Marshall, M.W., Leon, R., Grey, T.L., Ferrell, J.A., Dotray, P.A., Jordan, D.L., Grichar, W.J., Brecke, B.J. 2013. Glufosinate application timing and rate affect peanut yield. Peanut Science. 40(2):115-119.

Interpretive Summary: The threat of glyphosate-resistant weeds, especially Palmer amaranth, has caused growers to consider the use of herbicides with alternative modes of action in cotton and soybean. Glufosinate is a non-selective, broad-spectrum, postemergence herbicide that can be effectively used for the control of GR-Palmer amaranth in glufosinate-resistant crops. Since peanut is grown in close proximity to both cotton and soybean in the southeast US, drift or sprayer contamination problems frequently occur. Research was conducted at thirteen locations across the United States peanut belt during 2010-2012 to evaluate peanut response to postemergence applications of glufosinate over a range of dosages. Peanut yield loss increased with increasing glufosinate rate. When applied at 30 days after planting, peanut yield loss ranged from 8 to 90%, with 13% rate of yield loss from each 100 g/ha of glufosinate. Yield loss ranged from 17 to 88% and 25 to 85% when glufosinate was applied at 60 and 90 DAP, respectively. Rates of yield loss declined as application date was delayed (11.6% and 9.8% yield loss for every 100 g/ha of glufosinate at 60 and 90 DAP, respectively). However, earlier application timings may have had more time to recover from glufosinate injury. These data provide peanut growers across the US with an estimate of potential yield losses off-target movement of glufosinate or when contamination of spray equipment with glufosinate is suspected. Based on the estimated yield losses caused by a known rate of glufosinate at three different growth stages, decisions can be made to determine if a peanut crop that is unintentionally treated with glufosinate should be managed for production or terminated.

Technical Abstract: Research was conducted at thirteen locations across the United States peanut belt during 2010-2012 to evaluate peanut response to postemergence applications of glufosinate over a range of dosages. Glufosinate was applied at 0, 41, 82, 164, 328 and 656 g ai/ha at 30, 60, and 90 days after planting (DAP) of peanut. There were significant interactions in peanut yield loss between application time and glufosinate rate, with a positive linear relationship with increasing glufosinate rate. At 30 DAP, yield loss ranged from 8 to 90%, with 13.4% rate of yield loss from each 100 g/ha of glufosinate. Yield loss ranged from 17 to 88% and 25 to 85% when glufosinate was applied at 60 and 90 DAP, respectively. Rates of yield loss declined as application date was delayed (11.6% and 9.8% yield loss for every 100 g/ha of glufosinate at 60 and 90 DAP, respectively). However, rate of yield loss alone does not adequately describe these data, as regression from later application timings had larger y-intercepts than earlier applications, reflecting greater yield loss from lower dosages. Coupled with high and similar yield losses (=85%) from the highest tested dosage across all application dates, demonstrated that earlier application timings may have had more time to recover from glufosinate injury. These data provide peanut growers across the US with an estimate of potential yield losses associated off-target movement of glufosinate or when contamination of spray equipment with glufosinate is suspected.