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ARS Home » Southeast Area » Dawson, Georgia » National Peanut Research Laboratory » Research » Publications at this Location » Publication #185107
Title: EFFECT OF TIMING ON POST-DIRECTED HERBICIDE TREATMENT IN COTTON

Author
item HAAS, J - AUBURN UNIVERSITY
item PATTERSON, M - AUBURN UNIVERSITY
item Faircloth, Wilson

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/24/2005
Publication Date: 6/1/2005
Citation: -

Interpretive Summary: not required.

Technical Abstract: Field studies were conducted at the Prattville Experiment Field near Prattville, AL and the Wiregrass Research and Extension Center, near Headland, AL in 2004 to evaluate several post-directed herbicide treatments applied to cotton approximately eight inches tall (fluometuron alone or in combination with mix partners) and 12 inches tall (prometryn and diuron alone or in combination with mix partners). Mix partners were glyphosate, MSMA, or pyrithiobac. Treatments were applied in 15 gallons of solution per acre using a single 15004 flat fan nozzle per middle. Plots were 4 rows (36 inches apart) and 30 ft long. Roundup Ready cotton was used in both trials and a blanket application of Roundup Weathermax was applied over both trials at the 2 L cotton stage to establish a height differential between weeds and crop prior to post-directed treatments. Weeds at Prattville included entireleaf morningglory and sicklepod. Weeds at Headland included large crabgrass and Palmer amaranth. The trial at Prattville was conventionally tilled and the trial at Headland was strip tilled. No in-crop mechanical cultivation was used with either study. Hurricane Ivan reduced yields at Prattville an estimated 60%. Late season morningglory control at Prattville varied from 83 to 45 percent. Residual herbicides alone provided a maximum 68% control. Adding glyphosate or MSMA to the residuals tended to increase control. Adding pyrithiobac did not improve morningglory control above the residuals alone. Sicklepod control varied from 93 to 48 percent. Residuals alone gave 59 to 63 percent control. Adding glyphosate or MSMA to fluometuron or diuron tended to provide better sicklepod control than mixtures with prometryn. Adding pyrithiobac to any of the residuals did not improve late-season sicklepod control. Fluometuron with glyphosate or MSMA applied approximately one wk prior to prometryn and diuron mixes tended to provide better late-season control of both weed species. Seed cotton yield was lower for prometryn alone or prometryn or diuron with pyrithiobac Late season large crabgrass control at Headland was good to excellent with all treatments (88 to 95%). Likewise, palmer amaranth control was good to excellent with all treatments(83 to 95%). Seed cotton yields ranged from 2009 to 2686 pounds per acre. Timing did not significantly affect weed control or yields at Headland.