Growth Retardant Effects on Grasses for Roadside1
- R. W. Duell,
- R. M. Schmit and
- S. W. Cosky
The present report deals with grasses grown under roadside conditions where some discoloration, due to retardants may be acceptable, and the suppression of seedstalks might justify the use of retardants. The cumulative effects of applications of retardants on grass stands treated in consecutive years have not been widely researched.
Twelve grasses, including cultivars within species, were grown without mowing and fertilization in replicated plots in two field trials. Breaking of dormancy and stages of development of these grasses were described relative to times of application of growth retardants that included 1, 2-dihydro-3, 6-pyridazinedione (MH); N-3-(1,1,1-trifluoromethylsulfonyl) amino-4-methylphenyl acetamide (MBR-6033); and 2, 4-dimethyl-5-(trifluoromethylsulfonylamido)acetanilide(mefluidide).
Grasses varied appreciably in their time of seedstalk elongation and hence, response to time of application of retardants with regard to seedstalk control. Loss of stand density was not appreciable after the 1st year of treatment, but after retreatment in the 2nd year grasses were generally thinned by retardants. MH did not significantly reduce the stand of tall fescue (Festuca arundinacea Schreb.) in the first trial. MBR 6033 showed no advantage over MH, but mefluidide resulted in good seedhead control of certain species at low rates of application.
Effectiveness of a retardant treatment on a grass polystand partially depends on the species and cultivars in the polystand. The components of compounded seed mixtures, to be sown where retardants will be used, should match in time of seedstalk development. An application time for the growth retardant can then be selected when seedstalks of all the grasses are just beginning to elongate. This will maximize their control.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 1980. . Copyright © 1980 by the American Society of Agronomy, Crop Science Society of America, Soil Science Society of America, and International Turfgrass Society, 5585 Guilford Rd., Madison, WI 53711 USA