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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #295229
Title: Tolerance evaluation of vegetatively established Miscanthus x giganteus to herbicides

Author
item LI, XIAO - University Of Georgia
item GREY, TIM - University Of Georgia
item BLANCHETT, BRIAN - University Of Georgia
item LEE, DEWEY - University Of Georgia
item Webster, Theodore
item VENCILL, BILL - University Of Georgia

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2013
Publication Date: 10/1/2013
Citation: Li, X., Grey, T., Blanchett, B., Lee, D., Webster, T.M., Vencill, B. 2013. Tolerance evaluation of vegetatively established Miscanthus x giganteus to herbicides. Weed Technology. 27:735-740.

Interpretive Summary: Miscanthus is a genus of perennial that is native to eastern Asia, but found throughout a wide climate range due to its superior adaptability. Miscanthus giganteus is a triploid with 57 somatic chromosomes, derived from a natural cross of Miscanthus sacchariorus (diploid) and Miscanthus sinensis (tetraploid). The triploidy resulted in sterility of this plant and it cannot produce viable seeds. M. giganteus has potential as a bioenergy crop due to its significant yield advantage compared to other grass bioenergy species. Grass weed control during crop establishment has been a major challenge in M. giganteus management as there are no herbicides currently registered for use in M. giganteus in the US. It is postulated that herbicides used on corn may be safe on M. giganteus, however there is little information on weed management for the establishment and survival of this crop. Therefore, greenhouse and field studies using ornamental pots were conducted in summer 2011 at Tifton, GA with the objective of screening potential herbicide combinations for M. giganteus when establishing from vegetative rhizomes. Thifensulfuron, metsulfuron, tribenuron, chlorimuron, halosulfuron, rimsulfuron, cloransulam, pinoxaden, bentazon and metribuzin did not reduce shoot height or shoot dry weight relative to non-treated control (NTC). Nicosulfuron, trifloxysulfuron, sulfometuron, clodinafop, fluazifop and pyrithiobac caused greatest injury, reducing plant height and biomass compared to the NTC. Sethoxydim, diclofop, flumioxazin, imazamox, imazapic and imazethapyr reduced plant heights or resulted in increased injury. Most treatments containing atrazine, metribuzin, pendimethalin, acetochlor, metolachlor and mesotrione did not cause significant injury or stunting of crop growth; however, EPTC at 4.5 kg ha-1 significantly reduced height and dry weight and oxadiazon resulted in higher injury compared to NTC. These data indicated that selected herbicides can be utilized for establishment of M. giganteus from vegetative rhizomes. Further experiments are needed in field trials to evaluate establishment success and weed control spectrum utilizing these herbicides. Moreover, considering the invasive potential of M. giganteus, several POST herbicides evaluated in this study like fluazifop, pyrithiobac and sulfometuron may be viable options to control this specie if becomes invasive.

Technical Abstract: In spite of the recent focus on herbicide resistant weeds, herbicide resistant weeds are not new to agriculture; the first herbicide resistant weed was documented in 1957, with the first widespread resistance occurring in common groundsel with atrazine in the early 1970’s. Glyphosate resistant weeds have rapidly developed in the U.S. to include 14 different weed species. The predominance of herbicide resistant weeds in our agroecosystems is a response to the dramatic change in selection pressure, especially the widespread use of glyphosate. The Weed Science Society of America assembled a panel of experts to review and evaluate herbicide resistance and develop best management practices to both hinder the development of herbicide resistance weeds and manage herbicide resistance when they occur. The best management practices include: 1) understand the biology of the weeds present, 2) reduce the soil seedbank, 3) plant into weed-free fields and keep them as weed-free as possible, 4) plant weed-free crop seed, 5) scout fields routinely, 6) use multiple herbicide mechanisms of action, 7) apply labeled herbicide rates, 8) utilize cultural practices to enhance crop competitiveness, 9) use mechanical and physical weed control practices to suppress weeds, 10) prevent movement of weed propagules, and 11) manage weed seed at harvest and post-harvest before they are incorporated into the soil seedbank. While all of these best management practices will not be applicable in every agroecosystems, implementation of some of these practices in each system should help delay the development of herbicide resistant weeds.