Selective Nimblewill (Muhlenbergia schreberi) Control in Cool-Season Turfgrass

Abstract

Isoxaflutole and mesotrione have been used to control creeping bentgrass in cool season turf, these experiments evaluate these two products for selective nimblewill control. Three experiments were conducted in Virginia and Tennessee to evaluate selective control options for nimblewill in cool-season turfgrass. Single applications of isoxaflutole control nimblewill more effectively than single applications of mesotrione. Nimblewill control 8 wk after initial treatment (WAIT) increased as mesotrione rates increased from 28 to 280 g ai/ha, and isoxaflutole rates increased from 28 to 168 g/ha. Isoxaflutole at 84 and 168 g/ha were the only single application treatments that controlled nimblewill greater than 80% 8 WAIT. However, sequential applications of isoxaflutole and mesotrione at 28 g/ha, 10 d apart controlled nimblewill 94 and 80%, respectively 8 WAIT. Triclopyr and fenoxaprop-p did not effectively control nimblewill and caused unacceptable turfgrass injury. Long-term control was not evaluated in these studies. However, it was concluded that isoxaflutole and mesotrione at appropriate rates and applied in sequence selectively control nimblewill without harming desirable turf.

Weed Control Options in Spring-seeded Tall Fescue (Festuca Arundinacea)

“…Likewise, McElroy and Breeden (2005) reported that tall fescue injury from mesotrione applications peaked 1 wk after treatment and had dissipated by 2 wk after initial treatment (WAIT). Askew et al (2004) and Willis et al (2005) Control was visually estimated as a percentage reduction of green tissue compared to nontreated plots due to the combined effects of discoloration, necrosis, and stand reduction at 22, 9, and 8 weeks after initial treatment for broadleaf plantain, henbit, and yellow woodsorrel, respectively. b Each mean represents the average of four different treatment combinations including full rate preemergence, half rate preemergence, half rate preemergence followed by quarter rate early postemergence, and quarter rate preemergence, early postemergence, and late postemergence.…”

“…Gmel.) (Willis et al 2005) without significantly injuring cool-season turfgrasses. Owing to the need to fill voids in the turfgrass canopy after weedy grasses are controlled, preliminary greenhouse and field trials were conducted in Virginia to test isoxaflutole and mesotrione for safety at seeding of tall fescue (Askew and Beam 2002).…”

Relative Competitiveness of Nimblewill (Muhlenbergia schreberi) with Tall Fescues and Kentucky Bluegrass

“…It is a native warm-season (C 4 ) perennial grass that thrives in lightly shaded areas and easily invades lawns, waste areas, and other disturbed sites [3]. Controlling nimblewill with herbicides is difficult and the weed presents a serious problem in horse pastures.…”

Growth and Biomass Allocation of <i>Muhlenbergia schreberi</i>

“…It is a native warmseason or C 4 perennial grass that thrives in lightly shaded areas and easily invades lawns, waste areas, and other disturbed sites [3]. In unmowed areas, nimblewill can grow to 20 -60 cm in height; however, it is more aggressive in shaded areas with a moist, rich soil.…”

“…In unmowed areas, nimblewill can grow to 20 -60 cm in height; however, it is more aggressive in shaded areas with a moist, rich soil. Nimblewill spreads by seeds and has slender culms that fall to the ground and root at nodes; however, the plants do not have true rhizomes or stolons [3]. Nimblewill is difficult to control with herbicides and poses a serious problem in pastures.…”