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What is 2,4-D?
The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is a selective, systemic plant growth regulator herbicide used for post-emergent control of weeds in grass crops such as corn, soybeans, small grains, sorghum and grass pastures. Certain formulations can also be used on 2,4-D tolerant soybeans in Minnesota. 2,4-D is also used for weed control in turf and lawns, forestry sites, and aquatic sites. 2,4-D has activity on numerous broadleaf annual, biennial, and perennial weeds and is one of the top selling herbicides in Minnesota.
2,4-D is a volatile chemical that has activity at low rates which can damage non-target plant species through spray drift and/or volatilization (vapor drift).
Tolerant Crops
The United States Department of Agriculture (USDA) has deregulated 2,4-D tolerant (Enlist) corn and soybeans. The United States Environmental Protection Agency (EPA) has approved two 2,4-D products, Enlist One and Enlist Duo, for use on Enlist crops.
2,4-D
| Pesticide Type | Herbicide (Group 4) |
|---|---|
| Chemical Class | Phenoxyacetic herbicide |
| Common Trade Names* | Enlist One, Enlist Duo, Weedone 638, Unison |
| Registration Status | EPA: Registered since 1940s MN: Registered |
| Structure |
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*No endorsement is implied in the referencing of trade names.
2,4-D - Formulations
There are many formulations of 2,4-D, but the most common forms used for agriculture are the ester and amine formulations and with the deregulation of 2,4-D tolerant crops, a choline salt formulation.
Ester formulations have higher vapor pressure, increasing their potential to volatilize. Weather and environmental conditions can affect the volatility, e.g., hot, dry weather can increase volatility. Some ester formulations have been formulated as long chain esters which make the molecule less volatile and are referred to as "low volatile" or "LV" esters. 2,4-D LV4 and 2,4-D LV6 are examples of the "low volatile" esters.
Amine formulations are less volatile than the ester formulations, even the LV formulations, but may provide slightly less weed control because they are less soluble on the plant's cuticle, meaning they are not absorbed as readily as the ester formulations.
Burndown applications in the spring and fall are a primary use, and volatility characteristics should be considered when choosing which formulation to use, amine being a better choice in the spring if sensitive plants are present. The ester formulations are best suited to early spring or fall application when temperatures are lower and the risk to sensitive plants is less.
Tank mixing may be another consideration when choosing formulation. Follow label instructions for determining tank mixes.
Both amine and ester formulations are labeled for certain in-crop uses in corn, sorghum and other small grains. Always follow label directions for growth stages and timing when determining which formulation to use.
2,4-D choline salt is another formulation; a new use for a 2,4-D choline salt allows over-the-top applications to genetically engineered (GE) corn and GE soybeans. 2,4-D choline is less prone to volatilization than its other forms. This choline salt formation is specifically available in Enlist Duo® and Enlist One® and used on Enlist crops. Enlist product labels have expanded requirements for crop stages, endangered species restrictions, tank mixing, nozzle selection and environmental restrictions. Please visit our 2,4-D Frequently Asked Questions page for more information on this formulation.
Last updated: 5/21/2024
