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Doveweed: a Growing Problem in Warm-season Turfgrasses

Figure 1. Doveweed patch in a St. Augustinegrass lawn.

Figure 1. Doveweed patch in St. Augustinegrass sod.

Ramon Leon, WFREC Weed Specialist

Doveweed (Murdannia nudiflora) is a summer annual weed species that belongs to the dayflower family. Over the last three years, this weed has become an important weed problem in residential lawns and sod production.

This weed has two key characteristics that make it successful. First, its seeds germinate late during the spring when soil temperatures reach 65-70°F. This represents a problem because at this time the effect of preemergence (PRE) herbicides applied in February or March might be too low to provide good doveweed control. Second, the leaves of this weed can be confused with St. Augustinegrass and centipedegrass leaves, and many people do not notice doveweed until the plants are large and are displacing the turf. Doveweed leaves are thick with a shiny rubbery texture. The plant produces creeping stems (stolons), and mowers can break these stolons spreading this weed across the field.

It is very important to keep in mind that doveweed prefers wet areas, so drainage issues or over-watering will favor the establishment and growth of this weed. For this reason, ensuring irrigation is not excessive is a key management practice to control this problem. Another cultural practice that plays a major role on doveweed management is mowing. Mowing too short and too frequently will favor doveweed because its leaves will grow horizontally avoiding the mower blades. Chose a mowing height that allows good ground cover , yet only removes a third of the turf leaf blades.

Figure 2. Individual doveweed plant showing flowers, fruits, and stolons with root in nodes.

Figure 2. Individual doveweed plant showing flowers, fruits, and stolons with root in nodes.

Control

Doveweed is easier to control before emergence than when plants are well established.  Atrazine is one of the most effective herbicides to control doveweed. A maximum rate of 1 lb. of active ingredient (ai) per acre (A) and no more than 2 lb. ai per year are recommended to achieve both adequate control and avoid turfgrass injury. Atrazine should be applied right before or soon after doveweed emerges to maximize control.

For PRE control, S-metolachlor (Pennant Magnum™), dimethenamid-P (Tower™), and indaziflam (Specticle™) are herbicides that can considerably reduce doveweed establishment, especially if the application is done closer to doveweed emergence timing. These herbicides also provide good control of other important weed species such as crabgrass and goosegrass, which emerge earlier in the spring. In order to control early emerging weeds and doveweed, split applications are preferred. For example, the first application is done at the end of February or early March and the second one 4 to 6 weeks after. In this way, we can extend PRE control until doveweed starts emerging.

If we observe doveweed emerging after PRE applications, we have several postemergence (POST) herbicides that will provide control, as long as the plants are less than 2 inches in size and have not produced stolons. Products containing 2,4-D and dicamba can provide fair control of doveweed. However, repeated applications or applications in combination with other herbicides will be required for adequate control. There are commercial products with formulations that combine 2,4-D or dicamba with other herbicides such as mecoprop-p, carfentrazone (Quicksilver™), thiencarbazone and iodosulfuron (e.g., Celsius™, Tribute Total™). This type of three− or four−way combination can provide enhanced doveweed control.

If the problem is limited to a small area, but doveweed has fully displaced the turf, it is probably easier and more effective to kill doveweed with a directed application of glyphosate (RoundUp™) and re-seed or re-sod the area.

Because doveweed seeds can live for several years in the soil, it will take two to three years of proper control to eliminate doveweed populations. Although herbicides are useful tools to control doveweed, the most important factor to prevent doveweed problems is to have vigorous healthy turf. Doveweed requires a lot of sunlight, so if the turf effectively shades the ground, doveweed will have a hard time growing and producing new seed.

For more information on managing turf weeds download:

2012 UF Turgrass Pest Control Guide

 

PG

Author: admin – webmaster@ifas.ufl.edu

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Permanent link to this article: http://jackson.ifas.ufl.edu/newsletters/2015/04/11/doveweed-a-growing-problem-in-warm-season-turfgrasses/