The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Hydramethylnon (CAS 67485-29-4)
- Chemical class
- Slow-acting insecticide that kills insects that eat it; used in baits.[1][2]
- Mode of action
- IRAC Group 20A: Mitochondrial complex III electron transport inhibitors: hydramethylnon[3]
- Signal word
- AMDRO Fire Ant Bait: Caution[2]
How the bait works
Worker ants carry the bait into the mound as food and feed it to the colony and the queen; the label says the queen is dead in about a week, which destroys the mound.[2]
Hydramethylnon is IRAC Group 20A, which blocks energy production in mitochondria.[3][1]
Getting the most from a bag
Apply in the early morning or late afternoon when ants are most active, not on soaking-wet ground, and do not water it in.[2]
Once the package is opened, the label says the bait keeps its effectiveness for up to 3 months if stored cool, dry and closed.[2]
Where it is used
Amdro Fire Ant Bait is labeled only for outdoor use on lawns, landscaped areas, golf courses, parks, commercial grounds and other non-cropland, plus grounds around poultry houses and animal holding areas.[2]
It is not for vegetable or other food crops, and companion animals grazed on treated pasture cannot be used for food or feed.[2]
Do not apply granules to pavement or other impervious surfaces, and do not apply if rain is likely within 24 hours.[2]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| AMDRO Fire Ant Bait[2] | AMBRANDS (Central Garden & Pet) | 73342-1 | 0.73% | granular bait | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| AMDRO Fire Ant Bait | Lawns and landscaped areas, broadcast | Imported and native fire ants, harvester, bigheaded and Argentine ants | 2–4 oz per 5,000 sq ft[2] 1 to 2 lb per acre with a hand-held granular spreader. No more than four broadcast applications a year, at least 30 days apart. |
| AMDRO Fire Ant Bait | Individual mounds | Fire ants and other listed ants | 2–5 level tbsp per mound[2] Sprinkle around the mound without disturbing it, using a disposable scoop, never a kitchen utensil. |
How to apply it, step by step
1. Protective gear
- The label requires no special gear; wash your hands with soap and water promptly after use and before eating, drinking, smoking or using the toilet.[2]
- Use a disposable scoop to measure it, never a kitchen utensil.[2]
2. Before you spray
- It's for lawns and landscaped areas, not vegetable gardens or other food crops.[2]
- Don't apply it if rain is likely within 24 hours or when the ground is soaking wet, and don't put the granules on pavement or other hard surfaces.[2]
- Keep people and pets out of the area during application, and keep animals from eating the granules.[2]
3. Mixing
- No mixing: the bait goes out dry, straight from the container.[2]
4. Applying
- Apply in early morning or late afternoon, when the ants are out foraging.[2]
- For a single mound, sprinkle 2 to 5 level tablespoons around the mound without disturbing it; the workers carry the bait back to the colony.[2]
- For large infested areas, broadcast 2 to 4 ounces per 5,000 sq ft with a hand-held spreader, no more than four broadcast treatments a year and at least 30 days apart.[2]
5. After you spray
- Don't water it in after application.[2]
- Repeat mound treatments as needed while the ants are active.[2]
First aid
- This label prints no first-aid section; it carries the CAUTION signal word and asks only that you wash with soap and water after handling.[2]
Storage, spills and disposal
- Store it in a cool, dry, secure place with the container closed and away from pets; once opened it stays effective for up to 3 months if stored properly.[2]
- For a partly full container, call your local solid waste agency, and never pour unused product down a drain.[2]
From the safety data sheet
- The SDS carries the workplace (GHS) signal word Danger because hydramethylnon may damage fertility or the unborn child; it also says the bait causes eye irritation and can form combustible dust in air. The EPA label's signal word for the same product is Caution.[4]
- If it gets in the eyes, rinse cautiously with water for several minutes, taking out contact lenses if it's easy to do, and get medical advice if irritation persists; if it gets on skin or clothing, take off the clothing and rinse the skin right away with plenty of water for 15 to 20 minutes, then call a poison control center or doctor for advice.[4]
- If someone swallows it, call a poison center or doctor if they feel unwell and rinse the mouth, but don't make them vomit unless medical staff say to; if someone breathes in the dust, move them to fresh air.[4]
- Sweep or scoop up spilled bait, don't let dust build up on surfaces, and sweep any granules that land on a driveway, sidewalk or street back onto the treated lawn so they don't wash into drains; the product is toxic to fish, so never apply it directly to water.[4]
- Store it in its closed original container in a cool, dry, well-ventilated place away from heat and open flame, locked up and out of reach of children.[4]
Safety and environmental hazards
People
The label signal word is CAUTION, with directions to wash with soap and water after handling and before eating, drinking or using the toilet.[2]
Pets
The label says not to apply it in a way that contacts any person or pet, to keep people and pets out of the area during application, and to store the container away from pets.[2]
Bees and pollinators
The Amdro label carries no bee warning; the bait is a granule spread on the ground and carried into the mound by worker ants rather than sprayed on plants.[2]
Fish and water
The label states it is toxic to fish and aquatic invertebrates; sweep any granules that land on driveways, sidewalks or streets back onto the lawn so they do not wash into drains.[2]
Common questions
- How much Amdro do I put on a fire ant mound?
- Sprinkle 2 to 5 level tablespoons around the mound without disturbing it.[2]
- How often can I broadcast Amdro on my lawn?
- No more than four broadcast applications a year, at least 30 days apart, at 2 to 4 ounces per 5,000 square feet.[2]
- Can I use Amdro Fire Ant Bait indoors?
- No. The label limits it to outdoor sites such as lawns, landscaped areas, parks and other non-cropland.[2]
- Why does old Amdro stop working?
- The label says an opened package keeps its effectiveness for up to 3 months when stored properly, so stale bait is less attractive to ants.[2]
Sources
- University of California Statewide IPM Program, “Home and Landscape Pesticide Active Ingredients Database: hydramethylnon.” ipm.ucanr.edu/home-and-landscape/pesticide-active-ingredients-database/active-ingredient-details/?uaiKey=20 (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “AMDRO Fire Ant Bait label, EPA Reg. No. 73342-1 (EPA-stamped, Apr. 8, 2024).” www3.epa.gov/pesticides/chem_search/ppls/073342-00001-20240408.pdf (accessed 2026-10-06)
- Insecticide Resistance Action Committee, “IRAC Mode of Action Classification Scheme, Version 11.5 (Feb. 2026).” irac-online.org/documents/moa-classification/ (accessed 2026-10-06)
- Ambrands (Central Garden & Pet), “AMDRO Fire Ant Bait Safety Data Sheet (Ambrands, issued May 12, 2014, revised January 13, 2020; EPA Reg. No. 73342-1, the page's product; distributor copy hosted by Orgill).” images.orgill.com/weblarge/10024/1320241-SDS.pdf (accessed 2026-10-19)