Author
GREY, T.L. - University Of Georgia | |
SOSNOSKIE, L.M. - University Of Georgia | |
Webster, Theodore |
Submitted to: University of Georgia Research Report
Publication Type: Experiment Station Publication Acceptance Date: 3/20/2010 Publication Date: 6/15/2010 Citation: Grey, T., Sosnoskie, L., Webster, T.M. 2010. Palmer Amaranth Control as Affected by Herbicide, Method of Application, and Winter Cover Crop. University of Georgia Research Report. 49-52. Interpretive Summary: Technical Abstract: Glyphosate-tolerant cotton allows growers to transition to conservation tillage, promoting soil conservation. Elimination of cultivation in conservation tillage shifts the weed control burden on herbicides. Glyphosate-resistant Palmer amaranth (PA) was discovered in 2004 and threatens effective weed control throughout the southern US. Herbicides with soil residual activity applied preemergence (PRE) can control PA. Cover crops, such as rye, are used in conservation tillage and assist in PA suppression. Combining herbicide-fertilizer impregnation (FERT) with conservation tillage may improve PA weed control. Cotton injury was similar for PRE and FERT treatments, with greater injury observed in 2008 than in 2009. Injury from S-metolachlor applied PRE was unacceptable in 2008; FERT did not prevent cotton injury from occurring. S-metolachlor PRE and FERT are not advised in cotton. Fomesafen controlled PA in all systems. PA populations were reduced by rye cover greater than wheat cover; rye produced 4,700 kg/ha dry biomass while wheat produced 1,120 kg/ha. PA was controlled effectively by a combination of fomesafen and rye. Fomesafen provided residual control of PA as either a PRE or FERT. PRE herbicide applications must be followed by POST application of glufosinate in order to provide adequate season long control in cotton when PA is glyphosate resistant. |