A Look Back at Weed Management Issues of 2024 - Part 3
All years present challenges when managing turfgrass, at least to some degree. In 2024 we endured an historic drought with conditions not seen since at least 1988. While the weather contributed to some of our management issues with weeds this year, we also saw either the introduction of, or an increase in, some new weed species. Most of these newer weed species can be difficult to control. This is a continuation of my discussion of these weeds including current management recommendations to deal with them.
False green kyllinga
In addition to yellow nutsedge, false green kyllinga is now a commonly seen sedge in Ohio. False green kyllinga is a different species that produces many rhizomes but not nutlets like yellow nutsedge (Figure 1). Because of this, it can spread and form mats in the turf, which can cause decline of the turfgrass. Sedges can be difficult to differentiate vegetatively but has easy to recognize flower structures. In almost all cases, the herbicides that are recommended can be used interchangeably for sedge and kyllinga control.
Pyrimisulfan is available in two formulations. Vexis is available as a granular formulation and Arkon is a newly labelled liquid formulation for postemergence control of sedges and kyllingas as well as certain broadleaf weeds including many winter annuals and buckhorn plantain. Since Vexis is a granular formulation that will reduce the chances for off target drift. Both products are labelled for use on residential and commercial sites, golf course fairways, tees and roughs and sports fields.
Other sedge control herbicides include Dismiss NXT which is a newer formulation that contains carfentrazone in addition to sulfentrazone, the active in Dismiss herbicide. This product is effective for control of sedges and summer annual broadleaf weeds. Halosulfuron (Sedgehammer) is also quite effective. Celero (Imazosulfuron) is labelled for control of yellow and purple nutsedge as well as annual sedges and kyllingas. It is marketed more for kyllinga control in southern turf but does show good tolerance when used on northern turf. Since it is a different class of chemistry it provides a good option for managing weed resistance.
Lesser celandine
Lesser celandine is an invasive species and a major threat to forest understories. It will also survive in managed turfgrass. It is a springtime ephemeral and persists as a perennial by bulbs. Control with selective herbicides has proven very difficult. Control recommendations for turfgrass based upon research are scarce but the general recommendation is remove it either manually by digging the bulbs or applying glyphosate when temperatures are above 50°F. Selective control may also be possible is you choose a combination herbicide with at least two of the following three active ingredients: MCPA, triclopyr and dicamba. An excellent discussion of this weed was prepared by Joe Boggs of the Buckeye Environmental Horticulture Team (BEHT)
Figure 2. Lesser celandine is an invasive species and a major threat to forest understories. It will also survive in managed turfgrass.