Germination of Seeds of Turfgrasses as Affected by Glyphosate and Paraquat

Abstract

Effects of glyphosate [N-(phosphonomethyl)glycine] and paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) on turfgrass seed germination were evaluated in the greenhouse. Glyphosate caused little effect on germination of Kentucky bluegrass (Poa pratensis L.), red fescue (Festuca rubra L.), and tall fescue (F. arundinacea Schreb.) when applied to the soil immediately before seeding or when applied directly over the seed on the soil surface. Paraquat sprayed directly over the seed on the soil surface prevented germination of most of the seeds of the three grass species. Covering seeds on the soil surface with clippings from grass turf sprayed with paraquat greatly reduced germination. About half of those that germinated either died later or were severely chlorotic. Covering seeds on the surface of the soil with clippings from turf that had been sprayed with glyphosate did not significantly reduce the number of seedlings established.