MESOTRIONE-IMPREGNATED FERTILIZER USE DURING ESTABLISHMENT OF COOL-SEASON TURFGRASSES

摘要

broadleaf weed control at seeding of cool-season turfgrasses.These studies were designed to determine if mesotrione impregnated on a granular fertilizer (MIF) would provide effective broadleaf and grass weed control while ascertaining if it would be safe to apply on Chewings fescue (Festuca rubra L.ssp.commutata Gaudin),perennial ryegrass (Lolium perenne L.),and Kentucky bluegrass (Poa pratensis L.).The experiments were carried out at Pullman,WA during summer 2006 and 2007.Treatments were: MIF applied at seeding and 6 wk later with mesotrione at 161,282,343,or 565 g a.i.ha-1,siduron impregnated on a fertilizer also applied twice at 6700 g a.i.ha-1,and a fertilized,untreated control.Mesotrioneimpregnated fertilizer provided acceptable (< 2 weeds 0.18 m- 2) broadleaf and grass weed control for all three turfgrass species.When applied to F.rubra,all mesotrione rates caused unacceptable levels of phytotoxicity and reduced percentage of turfgrass cover.In L.perenne,mesotrione at ≥ 343 g a.i.ha- 1,twice the label rate,was phytotoxic and at 565 g a.i.ha-1 reduced percentage of turfgrass cover.The MIF was not phytotoxic on P.pratensis regardless of rate.During the establishment of three major cool-season turfgrasses,MIF was effective at controlling a broad spectrum of broadleaf and grass weeds; however,care must be taken to choose the appropriate rate of mesotrione depending on turfgrass species at time of seeding.