Effects of a reapplication of growth retardants in a two year study on Kentucky bluegrass
Dernoeden, P.H.; Wehner, D.J.
Proceedings, Northeastern Weed Science Society, 1981 (Volume 35): 312-321
The growth retardants mefluidide at 0.25-0.5 lb, MBR-18 337 [4-ethylthio-N-methylsulphono- alpha , alpha , alpha -trifluoro-o-toluidide] 0.125-0.5 lb, ethephon 4-6 lb and EL-72 500 [ alpha -isopropyl- alpha -(4-trifluoromethoxyphenyl)pyrimidin-5-ylmethanol] 1-3 lb/acre were applied to a Kentucky bluegrass turf to evaluate growth suppression and turf quality during the second year of application under low management conditions. EL-72 500 at 2-3 lb/acre provided the best season-long combination of growth retardation and turf quality. Data indicated that mefluidide and MBR-18 337 treated plots sustained loss of density in 1979 as corroborated by high weed (Digitaria ischaemum) infestation in 1980. A mid-July trim mowing and application of fertilizer improved turf quality in EL-72 500 and ethephon treatments. Mefluidide and MBR-18 337 treated plants exhibited highest percentages of leaves bearing Helminthosporium vagans leaf spot lesions. EL-72 500 had no deleterious effects upon rooting when applied twice yearly during 2 successive years to the turf.