Nonchemical annual bluegrass (Poa annua) management in zoysiagrass via fraise mowing

Abstract

Continued reliance on chemical methods for controlling annual bluegrass has resulted in many populations evolving resistance to PRE and POST herbicides, particularly in warm-season turfgrass species such as zoysiagrass. Soil seedbank management is critically important when managing herbicide-resistant weeds. Fraise mowing (also spelled fraze, frase, and fraize) is a new turfgrass cultivation practice designed to remove aboveground biomass while allowing turf to regrow vegetatively. We hypothesized that this process would remove annual bluegrass seed and therefore be a mechanical means of controlling annual bluegrass in turfgrass. Zoysiagrass field plots were fraise-mowed in June 2015 only, June 2016 only, June 2015 and June 2016, or left untreated. The fraise mower was configured to remove the uppermost 25 mm of plot surface (i.e., 15-mm verdure and 10-mm soil). Annual bluegrass infestation was quantified in April following fraise mowing via grid count. Soil cores (10.8 cm diameter) were extracted from each plot after grid count data were collected to assess effects of fraise mowing on the soil seedbank. Moreover, replicated subsamples (7.6 L) of debris generated during fraise mowing were collected to better understand weed seed content removed during the fraise mowing process. Fraise mowing in June offered a slight reduction (24%) in annual bluegrass cover the following April. Whereas 28% of the seed in fraise-mowing debris consisted of annual bluegrass, there was no difference in the quantity of annual bluegrass seed remaining in the soil seedbank among fraise-mowed and non–fraise-mowed plots. Although fraise mowing may help to temporarily reduce existing annual bluegrass infestations via mechanical removal, the frequency and depth we studied did not effectively reduce the seedbank. Fraise mowing is a useful tool for providing mechanical suppression of annual bluegrass but it is not a replacement for properly timed herbicide applications.

Irrigation Timing as a Practice of Effective Weed Management in Established Alfalfa (Medicago sativa L.) Crop

“…An additional explanation for the shift lies in the mowing operations required for harvesting alfalfa. Harvest operations can control summer annuals in the stands of perennial crops [53,54]. It seems that several weeds (dominant in the initial harvests) were removed from the stand with the harvests of May and June, and the seeds of the later emergent species, e.g., redroot pigweed, germinated in increased quantities from July, resulting in the dominance of this species during August.…”

Fairway Renovation with Fraise Mowing Cultivation and Dazomet Fumigation

“…Baker et al (2005) reduced annual bluegrass cover in perennial ryegrass (Lolium perenne L.) stands by 50% after fraise mowing to 1.8 cm. Brosnan et al (2020), who fraise mowed 2.5 cm of material from Zoysia spp. stands, achieved annual bluegrass reductions of only 24% and reported little effect on the annual bluegrass seedbank.…”

“…One of the most prominent models today is the Koro FieldTopMaker (Campey Turf Care Systems, Cheshire, UK), which may be equipped with configurable rotors that strip or aggressively cultivate surface material at depths between 0 and 50 mm. Such innovations have expanded the application of fraise mowing to hybrid turf system grooming and hygiene, athletic field renovation, and warm-season turfgrass establishment and management (Brosnan et al, 2020;McCauley et al, 2019;Munshaw et al, 2017). No prior work has evaluated its use for cool-season golf course fairways.…”

Herbicide resistance in turfgrass: a chance to change the future?

“…Practices such as altering nutrient applications, alleviating soil compaction, and increasing mowing height have been shown to discourage weed infestation in turfgrass (Busey 2003). Spirited by the success of harvest weed seed control techniques in row crops, use of cultivation equipment for weed control in turfgrass has been explored recently (Brosnan et al 2020). Whereas researchers documented reductions in annual bluegrass with a mechanical device termed a "fraise mower," they observed no reduction in the quantity of annual bluegrass seed in the soil and increased quantities of other species as well.…”