Fact Sheet FS1309
This publication is intended for professionals who manage lawns, golf courses, athletic fields, and other turfgrass areas with cool-season turfgrass species. If you are a non-professional turfgrass manager see FS1308, Crabgrass Control in Lawns for Homeowners in the Northern US.
Introduction and Identification
Crabgrass (Digitaria spp.) and goosegrass (Eleusine indica) behave as true annuals in the northeastern United States (Figure 1). These plants germinate in the spring and grow rapidly throughout the summer as warm-season (C4) plants, mature in late summer, and produce seed before dying at the first frost in autumn. Each plant can produce thousands of seeds that remain viable in the soil for several years, making these annual weeds a perennial problem.
Smooth and large crabgrass (Digitaria ischaemum and D. sanguinalis, respectively) are the most common crabgrass species found in the northeastern United States (Figure 2). Crabgrass has a rolled stem (rounded vernation) and lime green, coarse-textured leaves. It typically has a prostrate growth habit, spreading out along the ground. Crabgrass seedheads appear finger-like with spikes (racemes) arising from different points at the top of the stem (Figure 3). The leaves and leaf sheaths of large crabgrass are typically covered in dense hairs, while those of smooth crabgrass are hairless (glabrous) and purple at the base. In the northeastern and mid-Atlantic regions, smooth crabgrass is more prevalent than large crabgrass.
Goosegrass is commonly found in highly trafficked areas with compacted soil and poor turfgrass cover. Goosegrass is most easily identified by its whitish, flattened stem (folded vernation) and prostrate growth habit (Figures 1 and 4). The seedhead (inflorescence) typically contains two to five racemes with seeds arranged in a herringbone pattern.
Managing and Controlling Crabgrass and Goosegrass
A dense stand of turfgrass is an effective way to prevent crabgrass and goosegrass. Supply adequate nitrogen fertility to maintain a dense canopy of desirable turfgrass by applying nitrogen fertilizer in early autumn and, if needed, in spring when cool-season grasses are more competitive than these warm-season weeds.
Research shows that mowing at the highest height recommended for your particular turfgrass species can significantly reduce crabgrass infestations compared to a low mowing height. Combining a higher height of cut with proper fertilization will create a dense turfgrass canopy that will shade the soil and create a more difficult environment for weed seedlings to survive.
If an irrigation system is available, irrigate deep and infrequently and only when the desirable turfgrass exhibits signs of low moisture. In New Jersey, grasses mowed at greater than 2 inches rarely need supplemental irrigation in the springtime.
Light and frequent irrigation throughout the growing season is not desirable as it keeps the soil surface moist and encourages weed seedlings to survive and grow. Desirable turfgrasses are more competitive under deep and infrequent irrigation since these grasses typically have deeper roots than crabgrass or goosegrass seedlings.
Goosegrass is especially competitive in soils commonly compacted by foot or equipment traffic and where turfgrass cover is poor. Traffic management combined with proper fertilization will increase the competitiveness of desirable turfgrass relative to goosegrass. If compacted soil is limiting the growth of desirable turfgrass, do not hesitate to aerify even if you have applied a pre-emergence herbicide. Research indicates that aerifying after a pre-emergence application will not disrupt the herbicide "barrier" in the soil.
Where severe crabgrass or goosegrass infestations are present in summer, a late summer or early autumn overseeding of cool-season turfgrass is a valuable management practice. Seeding at this time will fill the voids created as these weeds die, preventing crabgrass and goosegrass seedling survival the following spring. For more information on turfgrass fertilization and seeding, see FS108, Renovating Your Lawn and E327, Best Management Practices for Nutrient Management of Turf in New Jersey.
Both crabgrass and goosegrass are annual plants that cannot regrow if the crown (basal growing point) of the plant is removed. Crabgrass has a fibrous root system and the crown can be easily removed by hand or an upright weeding device such as Hound Dog® or Weed Hound®. As crabgrass matures it can also root at nodes on stems growing along the ground, but these are easily removed as well. Immature goosegrass plants can be removed mechanically, but as plants mature and the central taproot develops, it becomes more difficult to remove the growing point. Since seeds can germinate through the summer months, hand removal several times during this period may be necessary.
In areas with a history of infestations that cannot be managed with cultural practices and mechanical removal alone, herbicides are an effective and economical option when applied at the proper time and rate.
Goosegrass more so than crabgrass has a history of developing herbicide resistance if herbicides with the same mode of action are used in several consecutive years. Rotating herbicide mode of action or using multiple modes of action within the same year can delay the onset of herbicide resistance. For example, dithiopyr and prodiamine are common pre-emergence herbicides with the same mode of action (mitosis inhibitor). Using one or both herbicides in several consecutive years can select for goosegrass plants that are resistant to these herbicides. These resistant plants will set seed and become the dominant population over time. Controlling plants that survive pre-emergence applications with post-emergence herbicides, or applying both a mitotic inhibiting pre-emergence herbicide and a pre-emergence herbicide such as oxadiazon (that has a different mode of action) will delay the onset of herbicide resistance.
Especially in areas with a history of moderate to severe infestations, pre-emergence herbicides are more economical and effective than post-emergence herbicides. Most pre-emergence herbicides must be applied and watered into the soil before the weed seed germinates to be effective. After irrigation, these herbicides are adsorbed to organic matter in the surface ¼- to ½-inch of soil and are slowly degraded over several weeks by soil microbes and rendered ineffective.
Did You Know?
Herbicides adsorbed to the soil are slowly released into the soil solution over several weeks. Only in the soil solution are they available for root absorption and weed control. When in soil solution, herbicides are also susceptible to degradation by soil microbes, which renders them ineffective for weed control. Herbicide degradation triggers desorption of more herbicide from the soil. After enough herbicide is released and degraded it will no longer provide weed control.
Soil microbial activity increases with soil temperature, which accelerates herbicide breakdown and reduces the length of weed control. Particularly in summers with above-average rainfall, pre-emergence herbicides break down more rapidly and pre-emergence herbicide failure is more common.
An inadequate herbicide rate is a common cause of pre-emergence failure. In New Jersey, recommended herbicide rates for single applications include dithiopyr at 0.38 to 0.5 lb active ingredient (ai) per acre (A), prodiamine at 0.75 to 1.0 lb ai/A, and pendimethalin at 3.0 lb ai/A. Sequential application is another strategy to prevent failures, which divides the single application rate into two lower-rate applications. The initial application is made at the standard crabgrass pre-emergence timing and the second application occurs 6 to 8 weeks later. For example, dithiopyr could be applied at 0.25 lb ai/A in April and again at 0.25 lb ai/A 6 to 8 weeks later. A sequential application strategy provides better crabgrass control than a single application if the program is initiated several weeks before expected crabgrass emergence and is especially effective on sandy soils with low organic matter. Product labels often provide more information on the sequential application strategy.
Crabgrass typically germinates mid- to late April in central and northern New Jersey and early to mid-April in southern parts of the state. Forsythia is an excellent phenological indicator for crabgrass germination. When forsythia is in full bloom, crabgrass pre-emergent herbicides should be applied as soon as possible. Crabgrass will germinate earlier in bare soil, particularly on south-facing slopes and near hardscapes, than in areas with good turfgrass cover. Goosegrass typically germinates 3 to 4 weeks after crabgrass.
Pre-emergence herbicides should be applied to well-established, mature turfgrass. With the exception of mesotrione, do not apply any of the pre-emergence herbicides listed below if you plan to seed within several weeks after the application, as these herbicides will kill turfgrass seedlings. See the product label for more information on use before or after seeding, even if seeding was conducted the previous autumn. Products listed below are safe on most cool-season turfgrasses, but always refer to the label for turfgrass tolerance information especially where fine fescue (Festuca spp.) or annual bluegrass (Poa annua) are desired.
Immediate irrigation or rainfall after application is not usually necessary (unless weed seed germination is imminent) but is typically recommended within 2 to 7 days after application. See the product label for more information. Granular and liquid formulations are both effective if applied uniformly at the proper rate. Poor application uniformity, especially on slopes, is a common cause of pre-emergence herbicide failure. It is especially important to sweep the product off of sidewalks, roads, and other hardscapes to prevent runoff.
Effective pre-emergence herbicides are listed below (Table 1). Most pre-emergence herbicides are available as granular and sprayable formulations. Dithiopyr, prodiamine, and pendimethalin are equally effective for crabgrass control at the rates discussed below; goosegrass control varies by product. Older herbicides such as benfin (Balan), benefin + trifluralin (Team Pro), DCPA (Dacthal) are less effective than herbicides listed below and are not discussed.
|Mode of Action
|Dithiopyr (Dimension and others)
|Microtubule assembly inhibitor (WSSA1 Group 3)
|Dithiopyr provides post-emergence control of leaf-stage (pre-tiller) crabgrass, which is unique among pre-emergence herbicides. Delaying the application to take advantage of this early post-emergence control will extend the herbicide residual further into the summer. Dithiopyr does not provide early post-emergence control of goosegrass or other weeds. A single application at 0.5 lb ai/A or sequential applications at 0.25 lb ai/A will often provide season-long crabgrass control in New Jersey. To control goosegrass, the product label recommends a single application before crabgrass emergence at 0.25 lb ai/A and a second application at 0.5 lb ai/A 6 to 8 weeks later. In our research, this approach provided moderate goosegrass control.
|Pendimethalin (Pendulum and others)
|Microtubule assembly inhibitor (WSSA Group 3)
|In New Jersey, the recommended single application rate for crabgrass control is 3.0 lb ai/A or sequential applications at 1.5 lb ai/A. For goosegrass control, the product label recommends a single application at 1.5 to 2.0 lb ai/A before crabgrass emergence and a second application at 1.5 lb ai/A 5 to 8 weeks later.
In residential turfgrass and sod production, the pendimethalin rate is limited to a single application at 2.0 lb ai/A or two sequential applications at 1.0 to 1.5 lb ai/A. Higher rates may be used in nonresidential turfgrass.
|Prodiamine (Barricade and others).
Echelon is a combination of prodiamine and sulfentrazone.
|Microtubule assembly inhibitor (WSSA Group 3)
|A single application at 0.75 to 1.0 lb ai/A or sequential applications at 0.5 lb ai/A are recommended for season-long crabgrass control in New Jersey. For goosegrass control, split applications and higher rates are necessary and have provided moderate to good goosegrass control in our research. Up to 2.3 lb ai/A can be applied annually in tall fescue. Up to 1.5 lb ai/A can be applied annually in Kentucky bluegrass and perennial ryegrass. Fine fescue is limited to 0.5 lb ai/A annually. See the product label for use on bentgrass mowed at 0.5 inches or less.
|Oxadiazon (Ronstar and others). Use only granular formulations in cool-season turfgrass as the liquid formulation will cause severe turfgrass injury.
|Protoporphyrinogen oxidase (PPO) inhibitor (WSSA Group 14)
|Oxadiazon is more effective against goosegrass than dithiopyr, prodiamine, and pendimethalin but less effective against crabgrass. Programs that include oxadiazon in combination with dithiopyr, prodiamine, or pendimethalin can provide crabgrass and goosegrass control. Applications at 2.0 to 3.0 lb ai/A have provided significantly more goosegrass control than prodiamine and dithiopyr in our research. In areas with a history of severe infestation, sequential applications at 2.0 lb ai/A on a 6- to 8-week interval will provide better control than single applications. Oxadiazon cannot be applied to residential turfgrass or where annual bluegrass is a desirable species. Apply to dry turf and irrigate if rain is not expected overnight. Anderson’s Goosegrass and Crabgrass Preventer (oxadiazon + bensulide) is labeled for use on golf course putting greens.
|Mesotrione (Tenacity). Sprayable and granular formulations.
|Hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitor (WSSA Group 27)
|Mesotrione has less residual efficacy than other pre-emergence herbicides but can be safely applied at and shortly after the seeding of many cool-season turfgrass species and is especially useful for weed control in a spring seeding. When applied at seeding it will provide pre-emergence crabgrass and goosegrass control for 2 to 4 weeks. Mesotrione will also provide pre-emergence broadleaf weed control and yellow nutsedge (Cyperus esculentus) suppression. We recommend applying Tenacity at 5 to 8 fl oz/A (mesotrione at 0.15 to 0.25 lb ai/A) at seeding and again four weeks later. Do not apply to bentgrass, fine fescue, or zoysiagrass (Zoysia spp.). See the label for more information if seeding with mixtures that contain fine fescue.
|Photosystem II inhibitor (WSSA group 7)
|Similar to mesotrione, siduron has less residual efficacy than other pre-emergence herbicides but can be safely applied when seeding many cool-season turfgrass species including creeping bentgrass (Agrostis stolonifera) and fine fescue. Pre-emergence crabgrass control at lower siduron rates is generally less consistent than with mesotrione. Apply siduron at 6.0 lb ai/A for best crabgrass control. Siduron will not suppress yellow nutsedge and is less effective than mesotrione for pre-emergence goosegrass or broadleaf weed control.
|Bensulide (Bensumec or Betasan). Sprayable and granular formulations.
|Lipid synthesis inhibitor (WSSA Group 8)
|Bensulide is less effective against crabgrass and goosegrass than dithiopyr, prodiamine, pendimethalin, and oxadiazon but can be safely applied to golf course putting greens and colonial bentgrass (Agrostis capillaris). It is important to irrigate immediately following application. This product can be applied only to golf courses and residential lawns.
1Weed Science Society of America
In areas with a history of moderate to severe goosegrass or crabgrass infestations, it is more economical and effective to rely primarily on pre-emergence herbicides and use post-emergence herbicides where plants "escape" the pre-emergence herbicide. Relying exclusively on post-emergence herbicides is only recommended if pre-emergence herbicides are not an option or in areas with a history of very minor infestations.
The efficacy of post-emergence herbicides is highly dependent on crabgrass or goosegrass growth stage. Immature leaf-stage plants are much easier to control than tiller-stage plants. Crabgrass typically begins to tiller and mature rapidly beginning in mid- to late June. From early July through mid-August, effective post-emergence control will often require multiple applications at higher rates. Post-emergence herbicide efficacy usually improves again in late August once plants mature and temperatures cool.
After germination when the plant first emerges from the soil, the first leaf is the coleoptile and the plant is in the seedling stage (Figure 5). A few days later, another leaf (the first true leaf) will emerge and the plant is classified as a 1-leaf stage plant. Other leaves will continue to emerge until the 4- or 5-leaf stage, at which time the plant begins to tiller. In the leaf stage, the plant is more susceptible to herbicides or can be easily removed by hand. After the leaf stage, the plant enters the tiller stage. During the tiller stage, the plant is defined by the number of tillers (stems). Goosegrass and crabgrass are still relatively easy to control at the 1- to 2-tiller stage. After the 2-tiller stage, plants quickly become difficult to control, especially in bentgrass (Agrostis spp.) species where lower herbicide rates must be used. Above the 7-tiller stage most annual grassy weeds are very tough to control and the exact number of tillers present has no practical implications. See Table 3 for more information.
In New Jersey, crabgrass plants generally begin to tiller in mid- to late June while goosegrass begins to tiller in early to mid-July if no pre-emergence herbicide is applied. However, plants in ornamental beds or areas with little turfgrass competition will tiller more rapidly than in areas of moderate to dense turf cover. Plants that germinate in mid-summer after pre-emergence herbicides breakdown will mature much more rapidly due to warmer temperatures. Scouting problem areas to find these weeds before plants produce too many tillers will reduce the number of herbicide applications required for control and make hand weeding easier.
Most post-emergence herbicides will not control seedlings that germinate after application (i.e., provide residual control). Crabgrass and goosegrass will germinate through August in New Jersey. If drought, disease, killing existing weeds, or other conditions create voids in the turfgrass canopy, weed seeds will germinate in these voids. Thus, when applying a post-emergence herbicide in June, July, or early August, consider including a pre-emergence herbicide unless you plan to seed in the autumn.
Most herbicides listed below (Table 2) are available as sprayable formulations only. Products discussed are registered for use in cool-season turfgrass and will provide control of crabgrass and/or goosegrass when used according to the label instruction. See product labels for more information on turfgrass species tolerance and rates, especially where bentgrass or fine fescue species are desired. Most herbicides listed below will also provide control of other summer annual grasses such as yellow and green foxtail (Setaria pumila and Setaria viridis, respectively) and barnyardgrass (Echinochloa crus-galli). See the product labels for more information on controlling these and other grasses. Recommendations below assume conditions for active weed and turfgrass growth are present around the time of application. If goosegrass and crabgrass are under drought stress, herbicides will be less effective and may injure the desirable turfgrass. Fenoxaprop is especially sensitive to drought stress.
|Mode of Action
|Fenoxaprop-p-ethyl (Acclaim Extra). Last Call is a mixture of fenoxaprop and fluroxypyr.
|Acetyl CoA carboxylase (ACCase) inhibitor (WSSA Group 1)
|All major cool-season turfgrass species and zoysiagrass (Zoysia japonica). See the label for information on creeping bentgrass.
As crabgrass or goosegrass mature from the leaf to tiller stage, the application rate of fenoxaprop increases rapidly. For example, Acclaim Extra will control leaf-stage crabgrass and goosegrass at 13 fl oz/A, but 28 fl oz/A are required to control 3-tiller and 4-tiller plants. A crabgrass plant can advance from the leaf stage to 3-tiller stage in just a few weeks during the summertime. Adding a surfactant to Acclaim Extra can improve control.
In creeping bentgrass, do not apply more than 3.5 fl oz/A of Acclaim Extra. Multiple applications on 2- to 3-week intervals will be required to provide goosegrass and crabgrass control at < 5.0 fl oz/A. See the label for more information on application rates to various species.
Broadleaf herbicides such as 2,4-D, MCPA, or MCPP applied within five days before or 21 days after a fenoxaprop application will reduce grass control. For broadleaf and grassy weed control with fenoxaprop, use Last Call herbicide.
|Quinclorac (Drive XLR8). Quinclorac is a component of many products including Onetime, Q4, Quincept, and Solitare.
|Synthetic auxin (WSSA Group 4)
|All major cool-season turfgrass species and zoysiagrass. Fine fescues and creeping bentgrass are moderately tolerant.
Quinclorac does not control goosegrass but provides excellent control of some broadleaf weeds such as white clover (Trifolium repens).
There are many quinclorac-containing products that contain quinclorac at different rates. The rate of quinclorac is especially important to determine the efficacy of a product against crabgrass. Lower rates will provide broadleaf weed control, higher rates are required for crabgrass control. Quinclorac rates > 0.75 lb/A will control crabgrass. Quinclorac will generally provide acceptable crabgrass control at the 1-tiller growth stage; control can be inconsistent when applied at the 2- to 4-tiller growth stage. Sequential applications are often required to plants at the 5-tiller stage and larger.
With many quinclorac-containing products, including Drive XLR8, a methylated seed oil adjuvant is required for best performance. When selecting a product, see the label for more information about adjuvants.
|Hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitor (WSSA Group 27)
|Kentucky bluegrass, perennial ryegrass, and tall fescue. See the label for information on fine fescue species.
|Mesotrione will most effectively control crabgrass plants at the 3-tiller stage and smaller. Include a non-ionic surfactant. Apply Tenacity at 5 oz/A in perennial ryegrass or fine fescue and 8 oz/A in Kentucky bluegrass or tall fescue. Multiple applications on 2- to 3-week intervals may be necessary to provide complete control. Tank-mix with non-ionic surfactant (0.25% v/v). Applying granular fertilizer with at least 0.25 lb/1000 ft2 of water-soluble nitrogen within 2 days of a mesotrione application can improve crabgrass control. Mesotrione is more effective against crabgrass than goosegrass. Do not apply to bentgrass or zoysiagrass. Be aware that mesotrione causes crabgrass and goosegrass leaves to appear bleached for 7 to 14 days after application before plants die (Figure 6).
|Hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitor (WSSA Group 27)
|All major cool-season turfgrass species.
Pylex is extremely effective for goosegrass control and moderately effective against crabgrass. Pylex will provide control of leaf stage goosegrass at 0.25 fl oz/A. Pylex will usually control goosegrass regardless of growth stage when applied at > 1.0 fl oz/A. Pylex can be applied at up to 1.5 fl oz/A in most cool-season turfgrass species except creeping bentgrass where it can be applied at up to 0.25 fl oz/A. In creeping bentgrass, multiple applications at 0.25 fl oz/A on a 2- to 3-week interval are recommended if tillered plants are observed.
It is important to include methylated seed oil (MSO) or crop oil concentrate (COC) in the tank with Pylex. Applying granular fertilizer with at least 0.25 lb/1000 ft2 of water-soluble nitrogen within two days of a mesotrione application can improve crabgrass control. Pylex can be safely applied at 28 days after seeding for most cool-season turfgrasses. Do not apply to zoysiagrass. Be aware that Pylex causes goosegrass and crabgrass leaves to appear bleached for 7 to 14 days after application before plants die (Figure 6).
|2,4-D ester + MCPA + dicamba + carfentrazone-ethyl (SpeedZone)
|Protoporphyrinogen oxidase (PPO) inhibitor (WSSA Group 14) and synthetic auxin (WSSA Group 4)
|All major cool-season turfgrass species.
|SpeedZone is labeled for goosegrass control at 4 to 5 pints/A but it will not control crabgrass. Multiple applications will be required to control tiller-stage goosegrass. Applications can be made on a 30-day interval. Tank-mixing SpeedZone and Pylex will control multi-tiller goosegrass and eliminate bleaching symptoms caused by Pylex. Do not apply SpeedZone to bentgrass maintained at 0.5" or lower in the summertime or bentgrass injury may result. Use caution when applying SpeedZone in the summertime as 2,4-D ester can volatilize and cause off-target damage to sensitive plants nearby.
Organic herbicides are not as effective or consistent as synthetic herbicides. In an organic system, utilizing proper cultural practices is of the utmost importance. This includes mowing at the highest recommended height (typically 3 to 5 inches) for the turfgrass species in the lawn, as well as the proper fertilization, irrigation, and seeding discussed earlier in this publication.
Products that contains corn gluten meal or corn gluten hydrolysate rarely provide acceptable crabgrass control under severe weed pressure. It is worth noting that corn gluten meal contains a substantial amount of nitrogen fertilizer, which can increase turfgrass density and reduce crabgrass infestations. There are other products available for crabgrass control that contain soybean or other horticultural oils, but we are not aware of any research demonstrating efficacy of these products.
Organic post-emergence herbicides are typically non-selective and will be more effective at controlling small seedling weeds. These products will also injure or kill any surrounding turfgrass that is contacted with herbicide. Effectiveness of most organic herbicides is highly dependent on environmental conditions, and often provide more control as relative humidity and air temperature increase.
Effective crabgrass and goosegrass control requires the right combination of turfgrass management aligned with proper herbicide selection and application. A healthy and dense turfgrass canopy will reduce reliance on herbicides. Knowing the weed history of a particular site can help you develop an economical and effective strategy. For example, on a site with a history of moderate to severe infestations, a strong pre-emergence herbicide program is important. In this situation it is also likely that spot treatment with a post-emergence herbicide will be necessary, especially if the turfgrass canopy thins in mid-summer due to biotic or abiotic stress. In sites with a history of minor infestations and good turfgrass cover, you can expect pre-emergence herbicides to be very effective or choose to rely exclusively on mechanical removal and/or spot treatment with post-emergence herbicides.
|1 to 5-leaf2
|1 to 2-tiller
|3 to 4-tiller
|5 to 7-tiller
1While all options are effective, these options are preferred due to their residual pre-emergence control.
2Especially when applying post-emergence herbicides to small plants in early summer, consider applying a pre-emergence herbicide with a post-emergence herbicide to control seeds that can germinate through August.
Photo credits: Katherine Diehl (Figure 1), Matt Elmore (Figures 2 and 4–6), Eric Reasor (Figure 3).
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