As the saying goes “An ounce of prevention is worth a pound of cure.” During winter and early spring, turfgrass managers should be focusing on ways to prevent annual weeds in their turfgrass. January and February offer a good timing opportunity to apply pre-emergent herbicides.
Pre-emergent herbicides, as the name implies, help prevent the emergence of annual weed growth and aid in the establishment of a healthy turfgrass stand. To prevent annual weed establishment, these herbicides should be applied prior to weed germination. Pre-emergent herbicides are applied in the winter or early spring to prevent summer annual weeds such as crabgrass, foxtail, and goosegrass. When applied in the early fall, winter annual weeds are controlled. In addition to preventing annual grassy weeds, pre-emergent herbicides control a limited selection of common annual broadleaf weeds including (but not limited to) henbit, chickweed, lespedeza, and knotweed.
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Pre-emergent herbicides such as Prodiamine, Dithiopyr, Oryzalin, Oxadiazon, and Isoxaben from Quali-Pro are the best options for preventing annual grassy and/or broadleaf weeds in healthy turfgrasses. These herbicides control weeds during the germination process, so it is critical that they are applied prior to weed seed germination. As a rule of thumb, in the spring months, pre-emergent herbicides should be applied before average soil temperatures reach 55 degrees Fahrenheit.
The turfgrass manager should consider turfgrass species, the problematic weed species from previous years, and prior pre-emergent chemistries used, before deciding on a pre-emergent herbicide for an application. Prodiamine is generally the most cost effective and is very good at preventing crabgrass, but only offers limited control of annual broadleaf weed species. Dithiopyr is effective on more broadleaf weeds, when compared to Prodiamine, and has post emergent activity on early stages of crabgrass species. Oxadiazon is labeled for dormant turf applications on golf courses, commercial properties, parks, and sod farms and prevents a wide range of grassy and broadleaf weed species. Isoxaben is great at preventing establishment of hard to control broadleaf weeds but does not control grassy weeds.
Pre-emergent herbicides should be applied at proper rates and timings and applicators should read and follow all label instructions. To find out more about pre-emergent herbicides, please visit www.quali-pro.com to find a listing of products, or contact your local distributor or Quali-Pro Area Manager.
Southeast Sales Representative