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ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Plant Physiology and Genetics Research » Research » Publications at this Location » Publication #184206
Title: EFFECT OF POSTEMERGENCE HERBICIDES ON TRANSPLANTED GUAYULE

Author
item FOSTER, MICHAEL - TEXAS A&M
item Coffelt, Terry
item MAJEAU, G - UNIV OF AZ MAC
item MAIN, M - UNIV OF AZ MAC

Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2004
Publication Date: 5/14/2005
Citation: Foster, M.A., Coffelt, T.A., Majeau, G., Main, M.M. 2005. Effect of postemergence herbicides on transplanted guayule. Association for the Advancement of Industrial Crops Conference. p. 12

Interpretive Summary:

Technical Abstract: Broad spectrum weed control is essential for successful guayule production. Guayule is a perennial crop, and weeds must not only be controlled pre-emergence, but also during establishment and after the shrubs have grown too large to permit cultivation. A study was initiated in April 2003 at The University of Arizona, Maricopa Agricultural Center, to test the tolerance of transplanted guayule to four post-emergence herbicides. Sixty-day-old guayule seedlings consisting of lines N565, 11591, and AZ-2 were transplanted April 15 on raised beds spaced 1 m apart. The experimental design was a split block with guayule lines as main plots and herbicides as subplots with three replications. The following herbicides were applied on May 22 at 1/2x, 1x and 2x rates: Cadre (35, 70, 140 g ai/ha); Pursuit (35, 70, 140 g ai/ha); Pursuit Plus (0.5, 1.0, 2.0 kg ai/ha); and Staple (35, 70, 124 g ai/ha). The rates were determined from recommendations for weed control used in other agronomic crops: Cadre (peanuts); Pursuit (soybeans, field corn, peanuts, alfalfa); Pursuit Plus (soybeans, field corn); and Staple (cotton). Evaluations were made weekly by recording the number of plants in each treatment that exhibited chlorosis or were dead. Plant height and width were recorded in March 2004. One week following spraying, the percentage of guayule plants showing chlorosis ranged from 9 to 100 with no shrub mortality. There was less chlorosis in line N565 than in AZ2 or 11591. The greatest damage occurred with the 2x rates. Four weeks after treatment the plants were actively growing and only plants in the higher rates were showing chlorosis. Plant mortality occurred only in the 2x Pursuit Plus and Cadre treatments in the three lines. Six weeks after treatment there was no visible chlorosis and no plant mortality since the previous evaluation. Plant height was significantly lower in all treatments versus the control except in the 1x Pursuit treatment. Plant width was significantly different than the control only in the 2x Pursuit and Cadre treatment when compared to the control. Although significant differences occurred in plant height, latex and rubber and resin production may not be different when the shrubs are harvested at two-years of age in 2005. These harvests will determine whether plant production has been significantly affected by the herbicide treatments.