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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Crop Germplasm Research » Research » Publications at this Location » Publication #315745

Research Project: Improved Forage and Alternative Use Grasses for the Southern U.S.

Location: Crop Germplasm Research

Title: Herbicides for establishment of seeded pearl millet x napiergrass hybrids

item WILSON, G - Texas A&M University
item Burson, Byron
item BAUMANN, P - Texas A&M University
item JESSUP, R - Texas A&M University

Submitted to: Southern Pasture and Forage Crop Improvement Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2015
Publication Date: 8/10/2015
Citation: Wilson, G.B., Burson, B.L., Baumann, P.A., Jessup, R.W. 2015. Herbicides for establishment of seeded pearl millet x napiergrass hybrids [abstract]. Southern Pasture and Forage Crop Improvement Conference Proceedings, March 30-April 1, 2015, Apalachicola, Florida. 69:39.

Interpretive Summary:

Technical Abstract: The establishment of warm-season grasses in pastures from seed is difficult partly because of competition from both annual broad leaf and grass weed seedlings. Use of herbicides is often problematic because many that kill annual grass seedlings are detrimental to seedlings of the desired species. This study was conducted to evaluate the phytotoxicity of multiple herbicide groups on pearl millet x napiergrass (PMN) hybrid seedlings to develop a strategy for establishing commercial plantings of PMN hybrids. Field and greenhouse experiments were conducted from 2012 through 2014. In two greenhouse experiments, Plateau(R), Aim(R), Prowl(R), Dual(R), Metribuzin(R), Huskie(R), Permit(R), Aatrex(R), Warrant(R), and Direx(R) were foliar applied post-crop emergence to PMN hybrids at the 3-5 and 5-7 leaf stages. A chlorophyll content meter was used to determine total chlorophyll content of the leaves and visual ratings were made up to 30 days after treatment to assess the toxic effects. Chlorophyll contents were correlated to herbicide activity through declining chlorophyll values which reached zero upon plant death. Of the herbicides tested, Dual(R) (s-metolachlor; 0.10 lb a.i. /acre) and Direx(R) (urea; 0.53 lb a.i. /acre) were lethal to the PMN plants. A field study was conducted in 2014 to evaluate phytotoxicity of Plateau(R), Aim(R), Prowl(R), Dicamba(R), Huskie(R), Permit(R), Aatrex(R), Warrant(R), and Direx(R). These herbicides were applied individually and in nine specific combinations over-the-top of PMN plants at the 5-8 leaf stage. Chlorophyll content was highly variable and could not reliably be used to detect differences. However, visual ratings, morphological measurements, and yield data revealed differences among treatments and confirmed findings from greenhouse studies. Results from both greenhouse and field studies indicate Atrazine(R), Aim(R), Huskie(R), Warrant(R), Prowl(R), and Dicamba(R) and in combination with one another did not have detrimental effects on PMN seedlings; therefore, they have potential in a weed management strategy.