See national chem pricing trends in the FBN Research report
Atrazine 101: Everything Farmers Need to Know About Atrazine
This guide includes the following sections:
What Is Atrazine?
Atrazine is a selective, systemic herbicide that offers pre- and post-emergence control of grass and broadleaf weeds in row crops, including corn, sugarcane, and sorghum. It has been used extensively in corn production in the United States since the 1960s. Today, according to USDA National Agricultural Statistics Service, it’s applied to more than 60% of all U.S. corn acres.
It’s become one of corn's most widely used herbicides because it is highly efficacious and relatively affordable. Some atrazine herbicides are labeled for use on wheat, macadamia nuts, and guava, as well as for non-agricultural uses such as managing roadsides, ornamentals, and turf. Atrazine is also a widely recommended tank mix partner for other corn herbicides.
How Does Atrazine Work?
Atrazine is a Group 5 photosynthesis inhibitor herbicide in the triazine family, which also includes the active ingredients prometryn and simazine. It controls weeds by inhibiting the function of the Photosystem II complex, reducing photosynthesis rates, and diminishing plant growth.
How Long Does Atrazine Take to Work?
Atrazine is a systemic herbicide that is taken up by a weed’s roots and transported to actively growing plant tissue. It causes severe oxidative damage to a weed’s proteins, lipids, and pigments, eventually resulting in cell membrane destruction and plant death. Atrazine is a relatively slow-working herbicide; visible plant effects may not appear until 14 to 21 days after an application and often include a gradual wilting and drying out of the weed.
Variables affecting how quickly atrazine is taken up and translocated throughout the target weed can include:
Temperature
Relative humidity
Rainfall following application
Soil moisture
Plant stress
Light availability
Atrazine Application Best Practices
As a systemic herbicide, atrazine is most effective under conditions that favor healthy plant growth. While it does have some foliar activity, atrazine is often tank-mixed with common contact herbicides for more effective control of emerged weeds in pre-plant applications.
Atrazine can be applied pre-plant, at-plant, or post-emergence in corn and sorghum.
Atrazine is a restricted-use pesticide, and runoff is a concern, especially near sensitive environmental areas and bodies of water. To reduce the risk of runoff and surface water contamination, follow label instructions and best application practices to protect waterways.
Atrazine application rates will vary depending on the:
Product
Application timing
Tillage method
Crop
Targeted weed species
Environmental conditions
Typical rates for GCS Atrazine 4L* in corn are:
Current atrazine label requirements for corn and grain sorghum impose an application limit of 2.5 pounds of active ingredient per acre (lb. ai/A) per calendar year. Additionally, there is a per-application maximum of no more than 1.6 or 2 lb. ai/A depending on soil erodibility and the amount of crop residue cover. These limits are cumulative for all products, including premixes, that may contain atrazine as an active ingredient. Consult specific product labels for recommended application rates.
How to Tank Mix with Atrazine
Some weeds resistant to glyphosate are sensitive to atrazine, making it an excellent tank mix partner in any corn weed control program. It is compatible with many common corn herbicides and is included in many premix products.
Common tank mix partners for GCS Atrazine 4L include:
metolachlor***
metolachlor + paraquat*
metolachlor + glyphosate
metolachlor + simazine
metolachlor + simazine + paraquat
metolachlor + simazine + glyphosate
propachlor
alachlor
alachlor + glyphosate
alachlor + paraquat
paraquat
simazine
simazine + paraquat
simazine + glyphosate
glyphosate
butylate
***Includes metolachlor and s-metolachlor
An emulsifiable oil or oil concentrate is recommended to enhance atrazine efficacy, especially for post-emergence, water-based applications.
Atrazine Label Updates
The United States Environmental Protection Agency (US EPA) is reviewing atrazine’s registration, which could change the allowable maximum use rates in coming seasons. Additionally, it could fall under new requirements associated with enforcing the Endangered Species Act, which may add more application restrictions. Consult with your local agronomist for the latest atrazine label updates.
Are you spray compliant? Find out what farmers need to know about the proposed EPA herbicide label updates in this FBN blog.
Atrazine Resistance Management
Atrazine has been widely used in row crop production for decades, making it a vulnerable target for developing herbicide resistance. The International Herbicide-Resistant Weed Database reports that 66 weed species are resistant to atrazine worldwide as of 2024. Atrazine-resistant waterhemp and Palmer amaranth populations have expanded throughout corn-growing geographies in recent years, making the herbicide less effective on these troublesome weeds.
Use these tips to reduce your risk of developing atrazine-resistant weed populations.
Make timely herbicide applications when weeds are 4” or smaller
Use multiple modes and sites of action
Employ crop rotation to diversify herbicides
Use layered residuals to extend the window of weed control
Add effective adjuvants to improve spray performance and plant uptake
Scout fields after applications to verify the application was effective
Add cultural or mechanical weed control practices, including tillage where appropriate
Learn how to manage 5,000 pests through the FBN Pest Solutions pages.
Atrazine Human and Environmental Safety Guidelines
While atrazine is relatively safe from a human toxicity standpoint, applicators should still use best safety practices when using the product.
Do not enter treated areas during the 12-hour restricted entry interval (REI) or until the spray solution has dried.
When handling atrazine, wear appropriate personal protective equipment (PPE), including a long shirt, pants, and close-toed shoes.
Wash your hands after handling the herbicide and remove clothing and PPE immediately if the product gets inside.
Follow all label instructions to ensure the safe use of atrazine.
Atrazine is toxic to aquatic invertebrates, so proper precautions must be taken when applying it to fields near sensitive environmental areas. This includes:
Avoid applying directly to water, areas where water is present, or intertidal areas below the mean high-water mark.
Avoid applications when weather conditions favor drift from treated areas. Runoff and drift from treated areas may be hazardous to aquatic organisms in neighboring areas.
Be mindful of residual chemical contamination when disposing of equipment washwaters or rinsate.
Buy Atrazine from FBN
Whether you prefer to customize an atrazine tank mix or apply a premixed herbicide, FBN has you covered:
Combine GCS Atrazine 4L* with Willowood Paraquat 3SL or Willowood Glypho 5 for effective broad-spectrum weed control.
Or, choose a premix like Fearless Xtra 5.6L* (acetochlor + atrazine) or MesoXtra Herbicide* (atrazine + mesotrione + metolachlor) for added convenience.
For a complete weed control solution, add label-required adjuvants like IN-Plant™ Crop Oil Concentrate (COC) for even more cost savings.
With a convenient online platform, transparent pricing, and direct-to-farm delivery available on your schedule, FBN puts Farmers First®.
Related Resources
Herbicides 101: Everything Growers Need to Know About Herbicides
Crop Nutrition 101: Everything Growers Need to Know About Crop Nutrition
Clethodim 101: Everything Growers Need to Know About Clethodim
Glufosinate 101: Everything Farmers Need to Know About Glufosinate
Glyphosate 101: Everything Farmers Need to Know About Glyphosate
Fungicides 101: Everything Farmers Need to Know About Fungicides
Insecticides 101: Everything Farmers Need to Know About Insecticides
Inoculants 101: Everything Farmers Need to Know About Inoculants
Biostimulants 101: Everything Growers Need to Know About Biostimulants
Copyright © 2014 - 2024 Farmer's Business Network, Inc. All rights Reserved. The sprout logo, “Farmers Business Network”, “FBN”, “FBN Direct” are servicemarks, trademarks or registered trademarks of Farmer's Business Network, Inc.
Parallel® is a registered trademark of ADAMA Group Company.
All other trademarks are the property of their respective owners.
GCS Atrazine 4L is a restricted use pesticide.
Parallel® is a restricted use pesticide.
Willowood Paraquat 3SL is a restricted use pesticide.
Fearless Xtra 5.6L is a restricted use pesticide.
MesoXtra Herbicide is a restricted use pesticide.
*Restricted Use Pesticides due to acute toxicity. For retail sale to and use by certified applicators only – NOT to be used by uncertified persons working under the supervision of a certified applicator.
FBN Direct products and services and other products distributed by FBN Direct are offered by FBN Inputs, LLC and are available only in states where FBN Inputs, LLC is licensed and where those products are registered for sale or use, if applicable. If applicable, please check with your local extension service to ensure registration status. Nothing contained on this page, including the prices listed should be construed as an offer for sale, or a sale of products. All products and prices are subject to change at any time and without notice. Terms and conditions apply.
ALWAYS READ AND FOLLOW LABEL DIRECTIONS. It is a violation of federal and state law to use any pesticide product other than in accordance with its label. The distribution, sale and use of an unregistered pesticide is a violation of federal and/or state law and is strictly prohibited. We do not guarantee the accuracy of any information provided on this page or which is provided by us in any form. It is your responsibility to confirm prior to purchase and use that a product is labeled for your specific purposes, including, but not limited to, your target crop or pest and its compatibility with other products in a tank mix and that the usage of a product is otherwise consistent with federal, state and local laws. We reserve the right to restrict sales on a geographic basis in our sole discretion. You must have a valid applicator license to use restricted use pesticides. Please consult your state department of agriculture for complete rules and regulations on the use of restricted use pesticides, as some products require specific record-keeping requirements.
The material provided is for educational purposes only. It is not intended to be a substitute for specific agronomic, business, legal, investment or professional advice. Where specific advice is necessary or appropriate, consult with a qualified agronomist, financial planner, or investment manager. Neither Farmer's Business Network, Inc. nor any of its affiliates makes any representations or warranties, express or implied, as to the accuracy or completeness of the statements or any information contained in the material and any liability therefore is expressly disclaimed.
Related content