Timing and Rate of Chaparral Treatment Affects Tall Fescue Seedhead Development and Pasture Plant Densities

Abstract

The herbicide, Chaparral, has been shown to suppress seedhead development in tall fescue (Lolium arundinaceum) pastures and reduce the symptoms of tall fescue toxicosis in cattle. However, little is known about the logistics of herbicide treatment on tall fescue pastures. The objective of this study was to determine the effect of three rates of Chaparral on tall fescue pasture when applied at three times (October, March, and April) during the growing season. Chaparral reduced seedhead densities of tall fescue on all treatment dates, but the highest levels of suppression were achieved with a late‐spring treatment, when tall fescue was in the early stages of reproductive growth. This treatment was also the least detrimental to tall fescue plant densities. Chaparral applied to vegetative tall fescue in the early spring had the least effect on seedhead densities but significantly reduced the density of tall fescue crowns. Other species of grass began to encroach into tall fescue stands following herbicide treatment during the fall and early spring. Delaying Chaparral until late spring may be more effective for producers because it may allow for greater control of seedheads with less loss in tall fescue and the potential for higher forage yields. There was some effect of suppressing reproductive growth of tall fescue with a fall treatment of Chaparral, but more research may be needed to evaluate its merit over a late‐spring treatment.

Effects of Aminocyclopyrachlor Plus Metsulfuron on Tall Fescue Yield, Forage Quality, and Ergot Alkaloid Concentration

“…As indicated by the reductions in tall fescue leaf yield and tiller density, total biomass yield reduction at spring harvest can be attributed not to just seedhead suppression, but also reductions in tall fescue vegetative growth per unit area. Goff et al (2014) observed reductions in tall fescue crowns and increased presence of orchardgrass and Kentucky bluegrass in response to aminopyralid plus metsulfuron applied in early spring.…”

“…In the same study, no differences were found within those treatments, also indicating that seedhead suppression can be achieved with lower rates of metsulfuron. Results from Kentucky studies have also shown aminopyralid plus metsulfuron reduces tall fescue seedheads (Aiken et al 2012;Goff et al 2014). Treatment with ACP plus 2,4-D resulted in higher seedhead density than the nontreated control.…”

“…Sather et al (2013) reported metsulfuroncontaining herbicides applied to vegetative tall fescue reduced seedhead density 14 to 61%. Researchers in Kentucky have also reported seedhead suppression with aminopyralid plus metsulfuron (Aiken et al 2012; Goff et al 2014). Although metsulfuron reduces tall fescue seedhead density, it also reduces forage yield (Moyer and Kelley 1995;Sather et al 2013).…”

Interaction of metsulfuron and nitrogen fertilizer in Tall Fescue forage systems

“…There was a tendency for orchardgrass to be greater (P=0.07) in the NEGCON, than the pastures receiving varying levels of Metsulfuron (MET0, MET67, MET134). Goff et al (2014) reported spring metsulfuron application to tall fescue pastures tended to increase the density of non-fescue cool season forage species (Kentucky bluegrass and orchardgrass) after one application. However, amongst other forage species recognized, botanical composition did not change (P>0.20) in response to treatment.…”