Cotton Stage of Growth Determines Sensitivity to 2,4-D

Seth A. Byrd, Guy D. Collins, A. Stanley Culpepper, Darrin M. Dodds, Keith L. Edmisten, David L. Wright, Gaylon D. Morgan, Paul A. Baumann, Peter A. Dotray, Misha R. Manuchehri, Andrea Jones, Timothy L. Grey, Theodore M. Webster, Jerry W. Davis, Jared R. Whitaker, Phillip M. Roberts, John L. Snider, Wesley M. Porter

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

The anticipated release of EnlistTM cotton, corn, and soybean cultivars likely will increase the use of 2,4-D, raising concerns over potential injury to susceptible cotton. An experiment was conducted at 12 locations over 2013 and 2014 to determine the impact of 2,4-D at rates simulating drift (2 g ae ha-1) and tank contamination (40 g ae ha-1) on cotton during six different growth stages. Growth stages at application included four leaf (4-lf), nine leaf (9-lf), first bloom (FB), FB + 2 wk, FB + 4 wk, and FB + 6 wk. Locations were grouped according to percent yield loss compared to the nontreated check (NTC), with group I having the least yield loss and group III having the most. Epinasty from 2,4-D was more pronounced with applications during vegetative growth stages. Importantly, yield loss did not correlate with visual symptomology, but more closely followed effects on boll number. The contamination rate at 9-lf, FB, or FB + 2 wk had the greatest effect across locations, reducing the number of bolls per plant when compared to the NTC, with no effect when applied at FB + 4 wk or later. A reduction of boll number was not detectable with the drift rate except in group III when applied at the FB stage. Yield was influenced by 2,4-D rate and stage of cotton growth. Over all locations, loss in yield of greater than 20% occurred at 5 of 12 locations when the drift rate was applied between 4-lf and FB + 2 wk (highest impact at FB). For the contamination rate, yield loss was observed at all 12 locations; averaged over these locations yield loss ranged from 7 to 66% across all growth stages. Results suggest the greatest yield impact from 2,4-D occurs between 9-lf and FB + 2 wk, and the level of impact is influenced by 2,4-D rate, crop growth stage, and environmental conditions. Nomenclature: 2,4-D; cotton, Gossypium hirsutum L.

Original languageEnglish
Pages (from-to)601-610
Number of pages10
JournalWeed Technology
Volume30
Issue number3
DOIs
StatePublished - Jul 1 2015

Keywords

  • Crop maturity
  • Enliste technology
  • boll distribution
  • epinasty

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