| Abstract/Contents: | "In 1955, thirteen herbicides were applied to bluegrass turf at U. Farm to quadruplicated plots, each 100 sq. ft. in area. The following acre rates of seven pre-emergence treatments were applied on June 10: 10 lb. dichloral urea, 4 lb. dichlorophenyl methyl butyl urea, 6 lb. chloro diethyl acetamide (CDEA), 8 lb. SES, 784 lb. alanap-lF, 4 lb. 2,4 dichlorophenoxy ethyl phosphite (3Y9) and 8 lb. 2,4 dichlorophenoxy ethyl benzoate (sesin). The latter four herbicides were applied again to the same plots on July 1 and July 22. The following or herbicides were applied three times (June 24, July 1, and July 8) as post-emergence treatments; 653 lb. Milcyanate (4% KOCN + 96% Milorganite), 8 lb. potassium cyanate (plus 1 lb. wetting agent), 8 lb. disodium methyl arsonate, and 4.5 gal. of 2 ½ percent PMAS. Two herbicides were applied when crabgrass was in the boot stage (July 22 and again August 5): 108 gal. Standard Crabgrass Killer, and 108 gal. Standard Spray C. Both of these are refined petroleum oils, the latter containing chlordane. All liquid herbicides, except the oils, were applied in 100 gal. water per acre at 30 psi pressure. Ratings of injury to crabgrass and bluegrass (scale: 0= no injury; 5= complete kill) were made on July 8, July 22, and August 23. Approximately one month after the first pre-emergence application, alanap 1F, 3Y9, sesin, and the dichlorophenyl urea all showed fairly good crabgrass control (3.0-3.8) without serious injury to the bluegrass (0.2-1.2). SES and dichloral urea were somewhat less effective in crabgrass control (2.2 + 2.5) and CDEA gave no control. By August 23, one month after the third application only sesin of the pre-emergence treatments showed much crabgrass control (2.5), but bluegrass injury with this treatment was moderately severe (2.2). Two weeks after the last application of the post-emergence herbicides, PMAS had given complete control of crabgrass (5.0) and disodium methyl arsonate about complete control (4.8), but both severely injured the bluegrass (3.0 and 3.5). Potassium cyanate and Standard Spray C. gave fairly good control (3.5 and 3.8), but the latter caused somewhat more temporary discoloration of the bluegrass. Bluegrass in plots treated with alanap lF, PMAS, Standard Crabgrass Killer, and Standard Spary C. was considerably more vigorous on September 23 than that in other plots. The poor fall development of bluegrass (e.g. untreated and CDEA) or residual injury by the herbicide (e.g. disodium methyl arsonate) or both." |
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