2,4-D Frequently Asked Questions

2,4-D is a selective systemic plant growth regulator herbicide primarily used for post emergence broadleaf weed control (for example: waterhemp, ragweed, horseweed) in a variety of crops grass (monocot) crops, including corn, small grains, sorghum, grass pastures, and 2,4-D tolerant soybeans. It is also used for weed control in turf such as residential lawns, sports fields, parks, and other areas. 2,4-D is Site-of-Action 4, synthetic auxin herbicide which is a type of growth regulator herbicide.

2,4-D has long been used in agricultural and nonagricultural herbicide products. The United States Environmental Protection Agency (EPA) has approved post-emergence use of two 2,4-D products, Enlist Duo (EPA Reg. No. 62719-649, DowDuPont) and Enlist One (EPA Reg. No. 62719-695, DowDuPont), on 2,4-D-tolerant (Enlist) corn and soybeans.

In Minnesota, waterhemp has evolved resistance to several herbicide classes (for example: glyphosate, ALS, PPO herbicides). These new 2,4-D products are approved for use in Enlist corn and soybeans to control herbicide-resistant weeds such as waterhemp. Also, palmer amaranth, Amaranthus palmeri, another aggressive species in the pigweed family has been found in a few Minnesota fields in recent years. Populations of this weed with resistance to glyphosate, ALS, PPO, and HPPD herbicides have been identified in other upper-Midwestern states.  

For more information on Palmer amaranth identification see the University of Minnesota Extension Minnesota Crop News, Be on the lookout for Palmer amaranth

2,4-D is a volatile chemical that may damage non-target plant species through spray drift and/or volatilization (vapor drift) or misapplication. Misuse of 2,4-D products may cause serious damage to sensitive plants species including non-2,4-D-tolerant crops like grapes, trees, ornamentals, etc. Some species are extremely sensitive to 2,4-D and show injury from low very low exposure.

The MDA requires 2,4-D product users to carefully read the labels and adhere to all label requirements and restrictions. The EPA granted a registration for Enlist One and Enlist Duo herbicides, but with additional restrictions. Label changes include:

• Application timing on Enlist soybeans changed from “through growth stage R2” to “through growth stage R1” (R1 = beginning flowering). This is to prevent application when crops are in bloom and may attract pollinators.
• Enlist product application is prohibited when rainfall is expected to occur within 48 hours and when soils are saturated or at field capacity.
• Irrigation within48 hours of application is prohibited.
• The product labels may require land managers, applicators and users of these products to implement land management practices (Mitigation Measures) based on hydrologic soil groups to reduce runoff. More information can be found on the manufacture's website listed on the label, Enlist Mitigation Measures to Manage Runoff.

The restriction for application to Enlist corn remains - Apply when corn is no larger than V8 growth stage or 30 inches (free standing) tall, whichever occurs first. Applications to corn with drop nozzles to avoid spraying into the whorl can be made to 30 to 48 inches plants.

Also, all applicators must follow the requirements specified in the Minnesota Pesticide Control Law.

The MDA encourages the reporting of all suspected or known 2,4-D damage. You can file a formal complaint by calling 651-201-6333 between 8:00 a.m. and 4:00 p.m. Monday through Friday or by completing an online complaint form. For more information, refer to the pesticide drift complaint process and timeline.

The labels of new 2,4-D products strictly prohibit the preemergence or postemergence use of old 2,4-D products on Enlist corn and soybeans. 2,4-D products that do not contain COLEX-D Technology are not approved for use with Enlist crops. Carefully read and follow all label requirements. 

Other 2,4-D products (LV4 ester, amine, etc.) can be applied preplant to Enlist crops, but must adhere to the required preplant intervals. Also consider herbicide resistance selection pressure from multiple applications of the same active ingredient in the same season.

No, there is no label mandatory training for the use of Enlist One and Enlist Duo for the 2019 growing season.

Yes, There are several requirements pertaining to the ESA and protecting species listed under the ESA

• Endangered Species Protection Bulletins must be obtained and followed for the geographic region where the application takes place. Bulletins must be obtained no earlier than 6 months prior to the application and the bulletin must be valid for the month of the application. More information on Endangered Species Protection Bulletins can be found on EPA's Endangered Species Protection Bulletins website.
• Enlist product application is prohibited when rainfall is expected to occur within 48 hours.
• Irrigation within 48 hours of application is prohibited.
• Applications are prohibited when soils are saturated or at field capacity.
• The product labels may require land managers, applicators and users of these products to implement land management practices (Mitigation Measures) based on hydrologic soil groups to reduce runoff. More information can be found on the manufacturer's website listed on the label, Enlist Mitigations Measures to Manage Runoff.

No, these products are not restricted use, so federal record keeping requirements do not apply.

Yes, commercial pesticide applicators must complete an application record as required by state law.

The federal labels prohibit post emergence application of these products to Enlist corn larger than V8 growth stage or thirty (30) inches (free standing) tall, whichever occurs first. For corn heights 30 to 48 inches (free standing), apply only using drop nozzles to avoid spraying into the whorl of corn plants. For post emergence use in Enlist soybeans, application is prohibited after the R1 (full flowering stage) growth stage. Make one to two applications to corn or soybeans with a minimum of 12 days between applications.

• Apply these products using label approved nozzles at manufacturer’s recommended spray pressure listed on the label. Use the minimum boom height based on the nozzle manufacturer’s direction.
• Do not apply at wind speeds greater than 15 mph.
• Do not apply under temperature inversion conditions.
• Do not substitute water with nitrogen solutions as spray carrier.
• Apply at label required application rates.
• Only apply with approved tank-mix products

Do not apply 2,4-D products when inversion conditions exist. The following are indicators of the presence of temperature inversion conditions:

• Calm day with wind speed less than 3 mph;
• Clear night;
• Dust cloud hanging on the side of the road;
• Dew or frost present on the ground;
• Horizontal smoke pattern;
• Ground fog in low-lying area.

No, the labels prohibit 2,4-D application if the wind is blowing toward susceptible plants listed on the label.

Commercially grown tomatoes, and other fruiting vegetables (EPA crop group 8), cucurbits (EPA crop group 9), and grapes are listed as susceptible plants on the new 2,4-D product labels.

The applicator must always maintain a 30 foot downwind buffer. To maintain the label required downwind buffer zone, the applicator must measure the wind direction prior to the start of any swath that is within 30 feet of a sensitive area. No application can be made in an area that is within 30 feet of a sensitive area if the wind direction is towards the sensitive area. Applicators can still use out-of-field non-sensitive crops and areas in the total buffer distance calculation. Follow all label requirements for the protection of sensitive areas.

Non-sensitive crops and areas include:

• Roads, paved or gravel surfaces;
• Areas covered by the footprint of a building, silo, shade house, feed crib, greenhouse, or other manmade structure with walls and or roof;
• Agricultural fields that have been prepared for planting; and planted agricultural fields containing crops other than those listed under the “Susceptible Plants” section of the label (the applicator must evaluate all factors and make appropriate adjustments when applying these products).

Any area other than the list of non-sensitive areas on the label are considered sensitive areas. For example: wooded area, water bodies, residential areas, etc.

Sometimes yes, but oftentimes buffers are required on several sides. Applicators should remember that buffers will often be required on two or more downwind sides of a target field if wind direction is not constant and non-target sites are not positioned completely perpendicular to one another. A 45-degree wind direction would require a buffer on two downwind sides.

Yes, regardless of who owns the wooded lot, it is label-defined as a sensitive uncultivated area that may harbor a sensitive plant species or endangered species. Therefore, even an adjacent wooded lot that you own or control is required to have a downwind buffer.