WeedMaster is a selective herbicide created by Nufarm for use after weeds have emerged (or post-emergent).
It effectively controls a wide range of broadleaf weeds and brush, including annuals, biennials, and perennials.
WeedMaster is formulated as a liquid and is commonly used in pastures, rangelands, hay fields, wheat, sugarcane, and fallow land.
Contents
Active Ingredient
WeedMaster herbicide contains two active ingredients that work together to control a wide range of broadleaf weeds and brush.
The first active ingredient is 2,4-D Amine Salt (35.7%), which belongs to the phenoxycarboxylic acid chemical class and disrupts normal plant growth processes. This disruption leads to uncontrolled and disorganized growth, ultimately causing plant death.
The second ingredient is Dicamba DMA Salt (12.4%), which also functions as a synthetic auxin, interfering with plant growth by mimicking natural hormones.
This product has 10.3% dicamba, which is about 1 pound in every gallon (or 120 grams in each liter), and 29.6% 2,4-D, which is around 2.87 pounds per gallon (or 344 grams per liter).
These two ingredients work synergistically to enhance weed control efficacy. They are absorbed through the leaves and roots of plants, translocated throughout the plant’s system, and accumulate in areas of active growth, leading to the disruption of vital growth processes and eventual plant death.
Application rate and timing
The application rate and timing of this herbicide depend on the type of weed and its size to work successfully.
In Tables 1 and 2, you can find the recommended rates for annual, biennial, and perennial weeds.
The weed sizes are shown in both inches and centimeters, and the application amounts are listed in pints per acre.
| Weeds Controlled (including ALS- and triazine-resistant) |
WeedMaster Rate Per Acre (according to weed growth stage) | |||||
|---|---|---|---|---|---|---|
| 0.5 pint/acre | 1.0 pint/acre | 1.5 pints/acre | 2 pints/acre | 3 pints/acre | 4 pints/acre | |
| Amaranth, Palmer | < 3” (7.6 cm) | 3 to 10” (7.6–25.4 cm) | – | – | – | – |
| Beebalm, Spotted | – | – | – | pre-bloom | post-bloom | – |
| Broomweed | 1 to 3” (2.5–7.6 cm) | 3” (7.6 cm) branching | – | branching | – | after branching |
| Buckwheat, Wild | – | 1 to 6” (2.5–15.2 cm) | – | – | – | – |
| Buffalobur | – | – | 1 to 6” (2.5–15.2 cm) | – | flowering | – |
| Burdock | – | pre-flower | – | – | – | – |
| Buttercup | – | pre-flower | – | early bloom | late bloom | – |
| Chickweed, Common | – | seedling | 1 to 3” (2.5–7.6 cm) | – | – | – |
| Cockle, Cow | – | < 3” (7.6 cm) | – | – | – | – |
| Cocklebur, Common | – | 1 to 6” (2.5–15.2 cm) | 6 to 12” (15.2–30.5 cm) | 12 to 18” (30.5–45.7 cm) | – | – |
| Coreopsis, Plains | – | 1 to 6” (2.5–15.2 cm) | – | – | – | – |
| Croton, Woolly | 1 to 4” (2.5–10.2 cm) | 4 to 12” (10.2–30.5 cm) | 12 to 30” (30.5–76.2 cm) | – | – | – |
| Devils-claw | – | – | – | < 8” (20.3 cm) | – | – |
| Dogfennel | – | – | – | 10 to 15” (25.4–38.1 cm) | – | – |
| Evening Primrose | – | < 2” (5.1 cm) | – | 2 to 6” (5.1–15.2 cm) | – | – |
| Flax | – | < 2” (5.1 cm) | – | – | – | – |
| Fleabane, Annual | – | 1 to 4” (2.5–10.2 cm) | 4 to 8” (10.2–20.3 cm) | 8” (20.3 cm) | – | – |
| Flixweed | – | < 3” (7.6 cm) | – | – | – | – |
| Henbit | – | – | preflower | – | flower | – |
| Knotweed Spp. | – | < 3” (7.6 cm) runners | – | > 3” (7.6 cm) runners | – | actively growing |
| Kochia | – | 1 to 6” (2.5–15.2 cm) | 6 to 10” (15.2–25.4 cm) | 10 to 20” (25.4–50.8 cm) | – | actively growing |
| Lambsquarters, Common | – | 1 to 6” (2.5–15.2 cm) | 6 to 10” (15.2–25.4 cm) | 10 to 20” (25.4–50.8 cm) | – | actively growing |
| Mallow, Common | – | < 3” (7.6 cm) | – | – | – | – |
| Marestail (Horseweed) | – | – | rosette to 3” (7.6 cm) | 3 to 6” (7.6–15.2 cm) | – | – |
| Mayweed | – | – | – | 1 to 6” (2.5–15.2 cm) | – | – |
| Morningglory, Ivyleaf | – | preflower | – | – | – | – |
| Morningglory, Tall | – | preflower | – | post-flower | – | – |
| Mustards, Annual | rosette | early bolt | – | – | – | – |
| Mustard, Tansy | – | < 3” (7.6 cm) | – | – | – | – |
| Pennycress, Field | – | – | – | rosette | – | – |
| Pepperweed, Virginia | – | – | 1 to 3” (2.5–7.6 cm) | 3 to 6” (7.6–15.2 cm) | after branching | – |
| Pigweed, Prostrate | – | < 3” (7.6 cm) | – | – | – | – |
| Pigweed, Redroot | – | < 3” (7.6 cm) | 3 to 10” (7.6–25.4 cm) | – | – | – |
| Pigweed, Smooth | – | < 3” (7.6 cm) | – | – | – | – |
| Pigweed, Tumble | – | < 3” (7.6 cm) | – | mature | – | – |
| Poorjoe | prior to flower | – | – | – | actively growing | – |
| Purslane, Common | < 3” (7.6 cm) | 3 to 8” (7.6–20.3 cm) | – | – | – | – |
| Ragweed, Common | – | – | – | – | > 10” (25.4 cm) | – |
| Ragweed, Western/Lanceleaf | 1 to 3” (2.5–7.6 cm) | 3 to 6” (7.6–15.2 cm) | 6 to 10” (15.2–25.4 cm) | actively growing | – | – |
| Sedge¹ | – | – | – | – | – | – |
| Shepherdspurse | – | rosette | – | – | – | – |
| Smartweed, Pennsylvania | – | < 4” (10.2 cm) | – | – | 4 to 12” (10.2–30.5 cm) | – |
| Sneezeweed, Bitter | – | 1 to 4” (2.5–10.2 cm) | prior to flower | flower | – | – |
| Sowthistle | – | rosette | – | bolting | – | – |
| Sunflower | – | 1 to 3” (2.5–7.6 cm) | 3 to 6” (7.6–15.2 cm) | 6 to 24” (15.2–61 cm) | – | – |
| Thistle, Russian | – | – | – | rosette | – | – |
| Velvetleaf | – | < 6” (15.2 cm) | 6 to 20” (15.2–50.8 cm) | > 20” (50.8 cm) | – | – |
| Waterhemp, Common | – | < 3” (7.6 cm) | 3 to 10” (7.6–25.4 cm) | – | – | – |
1. For use in non-food/feed crop only. Adding crop oil concentrate has shown to improve performance on actively growing annual sedge.
| Weeds Controlled | WeedMaster Rate Per Acre (according to weed growth stage) | |||||
|---|---|---|---|---|---|---|
| 0.5 pint/acre | 1.0 pint/acre | 1.5 pints/acre | 2 pints/acre | 3 pints/acre | 4–5 pints/acre | |
| Bindweed, Field | – | – | – | – | – | actively growing |
| Bittercress | – | 2 to 3” (5.1–7.6 cm) | – | – | – | – |
| Buckeye species¹ | – | – | – | – | full leaf | – |
| Bullnettle² | – | – | – | flower | – | – |
| Chicory | – | – | – | – | early bolting | – |
| Clover, Bur | – | – | pre-flower | – | – | – |
| Dandelion, Common | – | rosette | – | bolting | – | – |
| Dewberry, Southern¹ | – | – | – | – | – | spring or fall |
| Dock, Curly | – | – | prior to bolting | – | after bolting | – |
| Elderberry² | – | – | – | – | – | actively growing |
| Goldenrod, Missouri | – | – | – | 3 to 15” (7.6–38.1 cm) | flower | – |
| Goldenweed, Common | – | – | – | – | – | actively growing |
| Groundsel, Texas | – | rosette | post-bolting | – | – | – |
| Honeysuckle, Hairy | – | – | – | – | spring or fall | – |
| Horsenettle, Carolina¹ | – | – | – | – | – | flower or berry |
| Ivy, Poison | – | – | – | after bloom | – | – |
| Knapweed, Black² | – | – | – | – | – | actively growing |
| Knapweed, Russian² | – | – | – | – | – | actively growing |
| Knapweed, Spotted | – | – | – | – | – | actively growing |
| Marshelder | – | – | – | < 12” (30.5 cm) | 12” (30.5 cm)/prebloom | – |
| Mesquite | – | – | – | – | – | 45 to 90 days after bud-break |
| Milkweed, Antelopehorn¹ | – | – | – | pre-flower | – | flower |
| Nightshade, Silverleaf¹ | – | – | – | full flower | – | – |
| Nightshade, Black¹ | – | – | – | full flower | – | actively growing |
| Persimmon, Eastern³ | – | – | – | – | – | actively growing |
| Prickly Lettuce | – | – | – | rosette | – | actively growing |
| Rabbitbrush² | – | – | – | – | – | – |
| Ragwort, Tansy | – | – | – | rosette | – | actively growing |
| Redvine² | – | – | – | – | – | actively growing |
| Sagebrush, Fringed² | – | – | – | – | – | actively growing |
| Smartweed | – | – | – | – | – | – |
| Sorrel, Red | – | – | rosette | bolting | flower | actively growing |
| Sowthistle² | – | – | – | – | – | actively growing |
| Spurge, Leafy² | – | – | – | – | flower | full leaf |
| Tallow Tree, Chinese⁴ | – | – | – | – | – | full leaf |
| Thistle, Bull | – | – | rosette | bolting | – | actively growing |
| Thistle, Canada² | – | – | – | – | – | actively growing |
| Thistle, Musk | – | – | – | rosette/bolting | – | – |
| Thistle, Plumeless | – | – | rosette | bolting | – | – |
| Vetch, Hairy | 1 to 4” (2.5–10.2 cm) | 4 to 8” (10.2–20.3 cm) | 8” (20.3 cm) | full flower | – | – |
| Yankeeweed | – | – | – | 10 to 18” (25.4–45.7 cm) | – | rosette |
| Yellow Starthistle | – | – | – | – | – | rosette |
1. May require repeat applications.
2. Recommended rate will provide top growth suppression only.
3. For improved root kill or weedy species such as mesquite and eastern persimmon, spray 4 pints of this product per acre each year for 3 consecutive years. For increased control of weeds such as blackberry and dewberry, this product may be tank mixed with Purestand® or Ally® herbicide (0.1 to 0.2 ounces per acre), if labeled for the use site.
4. Under dense populations, a second application may be needed the following growing season.
Application Methods and Equipment
For aerial application, use between 3 and 10 gallons (11 to 38 liters) of water per acre. If the vegetation is thick or tall, use the higher amount of water.
For ground application or banding, you need to calculate how much product and water to use. The label of this herbicide suggests the following formulas:
- To find the amount of herbicide: (Band width in inches × broadcast rate per acre) ÷ row width in inches
- To find the amount of water: (Band width in inches × broadcast water volume per acre) ÷ row width in inches
In the case of ground application (broadcast), use between 5 and 40 gallons (19 to 151 liters) of spray solution per acre when treating the entire field.
Use more water if the vegetation is thick or tall. For spray equipment, choose nozzles that produce fewer fine (small) spray droplets. Keep the nozzle as close to the weeds as possible to ensure good coverage.
For spot or small area application, you can spray this product directly on small weed patches or individual plants using a handheld sprayer or similar tool. Spray enough so the leaves and stems are fully wet.
If using a backpack or other small sprayer, mix the herbicide in water following Table 3 (this assumes you are using 60 gallons per acre in a normal spray).
You can add a surfactant (0.5% of total volume) to help the herbicide stick better.
| Sprayer Capacity (gallons of water) |
Amount of WeedMaster to add to the spray tank |
|---|---|
| 1 gallon | 1 fluid ounce* |
| 3 gallons | 3 fluid ounces |
| 5 gallons | 5 fluid ounces |
*1 fluid ounce = 2 tablespoons
Tank Mix
WeedMaster herbicide can be tank mixed with other herbicides in many cases, but there are important conditions that must be followed.
Before mixing with another herbicide, you must always read the labels of both products and confirm that they are labeled for the same crops or sites, compatible in pH and formulation, and safe to mix.
If you are not sure, you should always perform a jar test. If you see clumping, separation, or any other reaction, it means the mixture is not safe to use.
| Aim™ (carfentrazone-ethyl) | Gramoxone® Extra (paraquat) | Ally® or Purestand® (metsulfuron-methyl) |
| Harmony® Extra or Treaty® Extra (thifensulfuron + tribenuron-methyl) | Amber® (triasulfuron) | Karmex® (diuron) |
| Asulox® (asulam) | Kerb® (pronamide) | Atrazine |
| Laddok® S-12 (bentazon + atrazine) | Banvel® or Diablo® (dicamba) | Landmaster® (glyphosate + 2,4-D) |
| Basagran® (bentazon) | Lexone® (metribuzin) | Bronate® or Maestro® Advanced (bromoxynil + MCPA) |
| MCPA | Buctril® or Maestro® 2EC (bromoxynil) | Paramount® (quinclorac) |
| Canvas® (thifensulfuron + tribenuron + metsulfuron) | Peak® (prosulfuron) | Clarity® or Clash® (dicamba) |
| Permit® (halosulfuron-methyl) | Outback® or Curtail® (clopyralid + 2,4-D) | Rave™ (dicamba + triasulfuron) |
| Cyclone® (paraquat) | Roundup Ultra® or Credit® (glyphosate) | Dakota® (fenoxaprop-p-ethyl + MCPA) |
| Sencor® (metribuzin) | Distinct® (diflufenzopyr) | Sinbar® (terbacil) |
| Evik® (ametryn) | Stinger® or Clean Slate® (clopyralid) | Express® or Victory® (thifensulfuron + tribenuron-methyl) |
| Tiller® (fenoxaprop-p-ethyl + 2,4-D + MCPA) | Fallowmaster® (glyphosate + dicamba) | Trooper® or Tordon® (picloram) |
| Finesse® (chlorsulfuron + metsulfuron-methyl) | Touchdown® (sulfosate) | Glean® (chlorsulfuron) |
| 2,4-D |
Surfactant and Other Additives
To help kill weeds that have already grown, you can mix this product with other helpers called additives. These include surfactants, liquid fertilizers (like 28-0-0 or 32-0-0), or crop oil concentrate (COC).
You can use these only on non-food or non-feed crops if you apply them after the weeds appear.
Important:
Do not use ammonium sulfate or crop oil concentrate on food or feed crops after the weeds have come up. For food or feed crops, do not use any liquid fertilizer that has ammonium sulfate (AMS) as a nitrogen source. This could cause too many leftover chemicals in the plants.
A crop oil concentrate can be made from petroleum or vegetable oil. It must meet all of these rules:
- It must not harm plants (non-phytotoxic).
- It must only have ingredients allowed by the EPA.
- It must mix well in a test jar.
- It should work well in real use in your local area.
Vegetable or petroleum oils should have emulsifiers in them to help them mix well. Refined vegetable oils work better than unrefined ones.
You may use oil concentrates before planting, before crops grow, or between crops. Do not use oil concentrate after crops grow (postemergence) in food/feed crops like sorghum, pasture grass, hay, sugarcane, or wheat.
When using nitrogen fertilizer, you can spray one quart per acre of liquid fertilizer (such as 28-0-0 or 32-0-0). However, do not use brass or aluminum nozzles with these fertilizers, as they may become damaged.
As for nonionic surfactant use, you should mix 2 to 4 pints of an 80% active nonionic surfactant with 100 gallons (379 liters) of water. If you are treating tougher weeds, you may use a higher rate of surfactant.
What to Wear When Using This Product
Anyone mixing, loading, applying, or handling the product must wear:
- Long-sleeved shirt and long pants
- Shoes and socks
- Protective eyewear
- Chemical-resistant gloves
- Chemical-resistant apron. Apron is required when applying postharvest dips/sprays to citrus, mixing/loading, cleaning spills, or handling concentrate.
Mixing Order
Tank mixing is important to achieve good final results. When using this herbicide, the correct mixing order is as follows:
- Water: Start by filling a clean sprayer tank halfway with clean water. Begin mixing.
- Agitation: Keep the water moving (agitated) during mixing and spraying.
- Products in water-soluble bags: If you are using products that come in water-soluble (PVA) bags, put them in the tank now. Wait until all the bags are fully dissolved and mixed in before adding anything else.
- Water-dispersible products: Add products like dry flowables, wettable powders, suspension concentrates, or suspo-emulsions next.
- Water-soluble products: Add water-soluble products such as WeedMaster herbicide.
- Emulsifiable concentrates: Add oil-based products (if needed).
- Water-soluble additives: Add things like liquid fertilizers (for example, 28-0-0 or 32-0-0), if needed.
- Finish with water: Fill the rest of the tank with water.
If you are using a sprayable liquid fertilizer instead of water, you must first mix WeedMaster with at least 5 parts water for every 1 part WeedMaster. Then, add 0.25% to 0.50% of a nonionic surfactant to help the mixture blend better.
How to Clean Spray Equipment After Use
After using this product, follow these steps to clean your sprayer:
- Rinse the outside and inside of the sprayer with water. While doing this, fill the tank halfway with clean water. Turn on the sprayer to flush out the system.
- Fill the tank again with clean water. Add 1 quart of household ammonia or 1/4 pint of Neutral-Clean for every 25 gallons (95 liters) of water. Run the sprayer for 15–20 minutes to circulate the mix through the whole system, and spray a little out through the nozzles. Let it sit for a few hours or overnight.
- Spray out the ammonia mix through the boom.
- Remove the nozzles and filters, then rinse the system by spraying two full tanks of clean water.
If you mixed this product with other types like wettable powders (WP) or emulsifiable concentrates (EC), you also need to rinse with detergent. Fill the tank with water and add 2 pounds of detergent for every 40 gallons (151 liters) of water. Run the pump so the detergent flows through all parts of the sprayer. Let the mix sit for a few hours or overnight.
Restrictions and Limitations
WeedMaster, like all herbicides, has certain rules and limits that you need to respect when using it.
- If you plant earlier than the time listed, the new crop might get damaged.
- Moist soil helps break down the herbicide, so if the weather is dry, it’s a good idea to loosen the soil to help moisture reach the herbicide.
- If you use 6 pints per acre or less, you can plant any crop after 120 days without any problem. For crops like barley, oats, wheat, or other grasses, you need to wait 10 days for every pint used per acre before planting.
- If you apply more than 6 and up to 8 pints per acre: in areas with at least 30 inches (76 cm) of yearly rainfall, you can plant corn, soybeans, sorghum, cotton (east of the Rocky Mountains), and other crops after 120 days. For barley, oats, wheat, and other grasses, wait 10 days per pint if east of the Mississippi River, or 15 days per pint if west. In drier areas with less than 30 inches of rainfall per year, wait at least 180 days before planting any crop.
- Do not use this product on crops that are under stress. Stress can be caused by drought (not enough water), hail, flooding, earlier herbicide damage, equipment damage, or big temperature changes. It may cause the herbicide to work poorly.
- Do not use on crops that are already damaged or showing signs of past herbicide injury like leaf burn or slow growth, as it could make the damage worse or last longer.
- Do not apply this herbicide through irrigation systems. Do not let it get into water used for drinking or in irrigation ditches.
If it rains or you water the field within 4 hours after spraying, the herbicide might not work as well.
Guidelines for Food and Animal Feed Crops
Pasture, Rangeland, and Grass (Hay, Silage)
You can use this product on pastures (even if the pasture is used to grow hay), rangeland, and grasses grown for hay or silage.
The only tank mixes you can use in this case are: Purestand, Ally, Amber, Diablo, Banvel, Clash, Clarity, and Rave.
You must follow the correct application rate depending on the type of weed or brush you want to control. Some weeds are harder to manage and may need to be mixed with another herbicide for better results.
If you use more than 4 pints per acre, it should only be for spot treatments. These instructions also apply to small grain crops like barley, corn, forage sorghum, oats, rye, sudangrass, or wheat, but only if they are being used for pasture, hay, or silage.
For new plantings of hybrid Bermudagrass, Pangolagrass, or stargrass (Cynodon species), apply 2 to 4 pints per acre after planting stolons (plant pieces).
The best time to apply is when weeds are just starting to grow, usually about 7 to 10 days after planting. If you wait until the weeds grow to 1 inch (2.5 cm) or more, or if they sprout later than 10 days after spraying, the herbicide will not work as well.
Do not use this product on bentgrass, sensitive grass pastures (like carpetgrass, buffalograss, or St. Augustine grass), or pastures with lespedeza, wild winter peas, vetch, clover, or alfalfa, because it will cause damage.
If you are preparing a pasture for reseeding, wait three weeks for every quart (or 2 pints) of product used per acre before planting new seeds, or the new plants may be harmed.
If you are growing grasses for seed or future planting, do not apply this product after the grasses reach the joint stage of growth.
Other rules for using this product on grasses grown for seed are:
- You can apply this product only twice per year at most.
- There must be at least 21 days between each application.
- Do not spray after the grass starts jointing (a growth stage when stems begin to grow upward).
- WeedMaster contains 1 pound of Dicamba active ingredient per gallon. You must not use more than 1 pound of Dicamba per acre in a single application.
There are specific grazing and feeding rules you need to follow after using this product to keep animals and food safe.
- For non-lactating animals: These animals can graze treated fields right after spraying. However, animals being raised for meat must not graze on treated areas within 30 days before slaughter.
- For lactating (milk-producing) animals: Do not allow them to graze treated fields until at least 7 days after spraying.
- For hay and silage: You can harvest treated grasses for dry hay or silage, but you must wait at least 7 days after the herbicide is applied.
Sorghum
When used on sorghum, this product can be tank mixed with one or more of the following herbicides: Atrazine, Basagran, Maestro, Buctril, Laddock S-12, Paramount, Peak, and Permit.
As application ratio, you can use 1 pint per acre when sorghum is in the 3 to 5 leaf stage (about 4 to 8 inches or 10 to 20 cm tall).
If you spray while the sorghum is growing quickly, the plants may bend or the leaves may curl. These effects are not permanent and usually go away in 10 to 14 days. Sorghum that is stressed may react more strongly to this product.
Do not use surfactants or oils when spraying this herbicide after the sorghum has emerged. Also, do not use this product if your sorghum field cannot handle a bit of crop stress.
Do not spray this product on sorghum that will be used to produce seed.
Surgarcane
You can mix this product with other herbicides like Asulox, Atrazine, Evik, Lexone, Sencor, and Sinbar.
You can apply this product once before the weeds come up (preemergence) or once after they appear (postemergence). In both cases, only one application is allowed per crop cycle, and the maximum amount is 5.5 pints per acre per application.
Wheat
In early season applications, apply 0.5 to 1 pint per acre, unless you are following a special program listed below:
- For spring-planted wheat, spray after the plant has started tillering
- For fall-planted wheat, apply after tillering but before the jointing stage
For the special program for fall-planted wheat only, you should apply up to 1.4 pints per acre after tillering to reduce perennial weeds like field bindweed. This application should be made in the fall, after the first frost but before a hard freeze.
To control more types of broadleaf weeds or grasses, you can mix this product with other herbicides like Purestand, Ally, Credit, or Roundup Ultra, if those products are allowed for use before harvest in wheat.
Preharvest Application:
To help manage weeds that interfere with wheat harvest, apply up to 1.4 pints per acre as a broadcast or spot treatment when the wheat is at the hard dough stage and the stems are no longer green.
For best results, spray while weeds are still actively growing but before they become too tall and begin to cover the crop.
You must wait 7 days after spraying before harvesting. If you want to use the wheat for seed, make sure the seed passes a germination test showing at least 95% germination.
As a precaution when using this product on wheat, you should know that postemergence use is limited to one application per crop cycle, with a maximum of 3.5 pints per acre per application. Preharvest use is also limited to one application, with a maximum of 1.4 pints per acre per application.
Corn (preplant and preemergence only)
WeedMaster can be used before or shortly after planting corn to control broadleaf weeds and existing cover crops. For preplant treatments, apply 1.25 to 2.5 pints per acre 7 to 14 days before planting.
This works with no-till, reduced-till, or conventional tillage systems. However, if the soil has less than 2% organic matter, do not exceed 2.0 pints per acre. Only one preplant application is allowed per crop cycle.
For preemergence use, apply 2.0 to 2.5 pints per acre 3 to 5 days after planting but before corn has emerged. This method is also suitable for all tillage types.
Do not use if corn seeds are planted shallower than 1.5 inches, or if the soil has less than 2% organic matter. Only one preemergence application is allowed per crop cycle.
Additional restrictions for both preplant and preemergence use include:
- Maximum 2.5 pints per application.
- Do not use on light, sandy soils or where soil moisture is too low.
- Do not apply to sweet corn, popcorn, or seed corn unless approved by the seed supplier.
- Do not replant treated fields with crops not labeled for 2,4-D and dicamba use.
- Limit use to 2 applications per year, with at least 30 days between applications.
- If using both a fall and spring application, total use must not exceed 5 pints per acre.
For best results:
- Use the higher rate for tougher or larger weeds.
- Mix WeedMaster with the right additives or other herbicides as shown on the label.
- When treating legume cover crops like alfalfa or clover, apply after 4 to 6 inches of regrowth.
- Avoid using equipment that moves too much treated soil over seed rows, as this can increase crop damage.
- Corn treated with this product can be harvested or grazed once it reaches the milk (ensilage) stage or later.
Soybean
This product can be applied before planting soybeans to control actively growing broadleaf weeds. The rate depends on how much time there is before planting:
- Apply 1.0 to 1.25 pints per acre at least 15 days before planting.
- Apply 1.25 to 2.5 pints per acre at least 30 days before planting.
After application, you must get at least 1 inch (2.5 cm) of rain or irrigation, followed by the full waiting period, before planting soybeans. These applications are only allowed before planting.
You can apply WeedMaster only once per growing season to soybeans, and no more than 2.5 pints per acre may be used. This herbicide is not recommended for use if you are not prepared to accept the risk of crop injury, including possible loss of stand or yield.
Avoid mowing or tilling the weeds before spraying, as this can reduce how well the herbicide works.
Also, do not use this product on coarse-textured soils (such as sandy soil) with less than 1% organic matter, or in regions with less than 25 inches (63.5 cm) of yearly rainfall.
Treated cover crops must not be grazed or harvested for feed or hay.
Cotton (Preplant only)
For cotton you need to apply 2.0 pints per acre at least 30 days before planting. For best results, spray when weeds are in the 2 to 4 leaf stage, and rosettes are less than 2 inches (5 cm) wide.
This use is allowed only before planting cotton, and should not be used post-emergence. After spraying, there must be at least 1 inch of rain or irrigation, followed by the full 30-day waiting period, before planting can begin.
Only one preplant application per acre is allowed before cotton is planted, and no more than two applications per year are permitted.
You should not apply this product if you are not ready to accept the risk of possible crop injury, which can include reduced plant growth or yield loss.
Avoid mowing or tilling weeds before treatment, as this can reduce weed control.
Do not use this herbicide on coarse-textured soil with less than 1% organic matter, or in areas where average yearly rainfall is below 25 inches (63.5 cm).
After using this product, you cannot replant other crops in the same season unless they are approved for preplant use with 2,4-D and dicamba. In addition, do not graze or feed livestock with hay, forage, or other materials from treated fields, and do not cut cotton for feed.
EPA Registration Number
The EPA registration number of the Weedmaster herbicide is 71368-34.
