Flumioxazin Tank-Mixtures with Six Herbicides for Annual Bluegrass (Poa annua) Control in Bermudagrass

Abstract

Flumioxazin is a protoporphyrinogen oxidase inhibitor with potential for POST annual bluegrass control and PRE smooth crabgrass control in bermudagrass. However, flumioxazin applications are often less effective in winter, compared with fall, because of reduced efficacy on mature annual bluegrass. The objective of this research was to evaluate tank-mixtures of flumioxazin with six other herbicide mechanisms of action for POST annual bluegrass control in late winter and residual smooth crabgrass control. Flumioxazin at 0 or 0.42 kg ai ha−1was evaluated in combination with flazasulfuron at 0.05 kg ai ha−1, glufosinate at 1.26 kg ai ha−1, glyphosate at 0.42 kg ae ha−1, mesotrione at 0.28 kg ai ha−1, pronamide at 1.68 kg ai ha−1, or simazine at 1.12 kg ai ha−1. Flumioxazin alone controlled annual bluegrass 61 to 70% at 8 wk after treatment (WAT) in three experiments from 2012 to 2014 in central Georgia. Flumioxazin tank-mixed with flazasulfuron, glyphosate, glufosinate, pronamide, and simazine provided good (80 to 89%) to excellent (> 90%) control of annual bluegrass at 8 WAT in 2 of 3 yr. These tank-mixtures were also more effective than flumioxazin alone in 2 of 3 yr, and control was greater or equal to the tank-mix partners applied alone. Treatments that included flumioxazin provided excellent (≥ 90%) control of smooth crabgrass at 6 mo after treatment in all 3 yr. Overall, tank-mixing flumioxazin with other herbicide chemistries may improve POST annual bluegrass control, compared with exclusive treatments, and effectively control smooth crabgrass in bermudagrass.

Annual Bluegrass (Poa annua) Biotypes Exhibit Differential Levels of Susceptibility and Biochemical Responses to Protoporphyrinogen Oxidase Inhibitors

“…Flessner et al (2013) reported that flumioxazin at 0.43 kg ai ha −1 controlled P. annua ≥95% up to a 2-tiller growth stage, but applications to plants with 4 to 6 tillers provided <50% control. Similar levels of POST P. annua control have been noted in field experiments with flumioxazin (Flessner et al 2013; Reed et al 2015). Moreover, there have been no reports of P. annua resistance to PPO inhibitors (Heap 2018), and flumioxazin offers an alternative mechanism of action for POST control of biotypes with resistance to other herbicides.…”

Zoysiagrass and weed response to herbicides during post-dormancy transition

“…The addition of flumioxazin to diquat, glufosinate, or glyphosate improved annual bluegrass control per day and final control at 84 DAT, but such improvement did not occur with oxadiazon admixture (Table 5). Reed et al (2015) also observed that flumioxazin tank-mixed with glyphosate was more effective than flumioxazin alone. Our results contrast with reports that combining contact-type modes of action herbicides with glyphosate could decrease weed control (Wehtje et al 2008, 2010).…”

“…However, control of certain weeds such as corn speedwell (Veronica arvensis L.), parsley-piert (Aphanes arvensis L.), and henbit (Lamium amplexicaule L.) with these herbicides has been inconsistent when they were investigated in bermudagrass and the herbicides have also injured dormant and semidormant bermudagrass (Derr and Serensits 2016;Johnson 1980). A large selection of herbicides other than hormone mimics, including acetolactate synthase inhibitors, photosystem II inhibitors, amino acid inhibitors, and cell wall biosynthesis inhibitors are routinely employed to control specific weed populations in dormant turfgrass (Brosnan et al 2012b;Johnson 1975bJohnson , 1984Reed et al 2015;Toler et al 2007).…”

“…However, these herbicides may injure zoysiagrass if green tissue is abundant during treatment (Rimi et al 2012; Velsor et al 1989; Xiong et al 2013). Tank mixing nonselective herbicides with residual products such as flumioxazin, oxadiazon, and indaziflam is a means of controlling existing winter annual weeds while also preventing subsequent summer annual weeds (Brecke et al 2010; Brosnan et al 2012b; Reed et al 2015). Some of the herbicide combinations mentioned above can be safely applied to actively growing turfgrass, but others must be applied to dormant turfgrass due to excessive injury potential (Brecke et al 2010; Johnson and Carrow 1999; Reed et al 2015).…”

“…Tank mixing nonselective herbicides with residual products such as flumioxazin, oxadiazon, and indaziflam is a means of controlling existing winter annual weeds while also preventing subsequent summer annual weeds (Brecke et al 2010; Brosnan et al 2012b; Reed et al 2015). Some of the herbicide combinations mentioned above can be safely applied to actively growing turfgrass, but others must be applied to dormant turfgrass due to excessive injury potential (Brecke et al 2010; Johnson and Carrow 1999; Reed et al 2015). Herbicides such as flumioxazin, indaziflam, simazine, diquat, flazasulfuron, foramsulfuron, trifloxysulfuron, foramsulfuron, sulfentrazone, 2,4-D + dicamba + MCPP + carfentrazone, 2,4-D + 2,4-DP + dicamba + carfentrazone, MCPA + dicamba + triclopyr, and 2,4-D + dicamba + fluroxypyr have not been examined for weed-control efficacy and zoysiagrass response prior to or during post-dormancy transition.…”