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
- Thiamethoxam (CAS 153719-23-4)
- Chemical class
- Neonicotinoid; IRAC Group 4A nicotinic acetylcholine receptor competitive modulators.[2]
- Mode of action
- IRAC Group 4A: Nicotinic acetylcholine receptor (nAChR) competitive modulators: neonicotinoids[2]
- Signal word
- Actara Insecticide: Caution[1]
Same group as clothianidin
Thiamethoxam shares IRAC Group 4A with imidacloprid, clothianidin, dinotefuran and acetamiprid, so alternating among them doesn't count as rotating modes of action.[2]
Where it is used
Apply when pest populations begin to build, before they reach economically damaging levels, with thorough spray coverage.[1]
Avoid relying on Group 4A insecticides all season against the same pest; rotate with other groups across generations.[1]
Each crop has its own rate range, seasonal maximum, interval between sprays and preharvest interval.[1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Actara Insecticide[1] | Syngenta Crop Protection, LLC | 100-938 | 25.0% | water-dispersible granule | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Actara Insecticide | Cucumbers, squash, melons, pumpkins and other cucurbits (one of many labeled crops) | Aphids and flea beetles (1.5 to 3.0 oz); cucumber beetles, leafminers and whiteflies (3.0 to 5.5 oz) | 1.5–5.5 oz product per acre[1] No more than 11.0 oz per acre per growing season, at least 5 days between applications, and a 0-day preharvest interval on cucurbits. |
Safety and environmental hazards
People
Signal word CAUTION: harmful if absorbed through skin, swallowed or inhaled, and causes moderate eye irritation. Avoid breathing dust or spray mist.[1]
Pets
It is an agricultural product applied under the Worker Protection Standard, not for home use.[1]
Bees and pollinators
Highly toxic to bees exposed to direct treatment on blooming crops or weeds. Don't apply or let it drift onto blooming plants while bees forage; crops under pollination contracts have extra restrictions.[1]
Fish and water
Toxic to wildlife and highly toxic to aquatic invertebrates; drift and runoff may harm aquatic life nearby.[1]
Common questions
- Is thiamethoxam a neonicotinoid?
- Yes. The Actara label identifies it as a Group 4A neonicotinoid.[1][2]
- Is thiamethoxam harmful to bees?
- The label says it is highly toxic to bees exposed to direct treatment on blooming crops or weeds.[1]
- How fast does Actara work?
- The label says it is rapidly taken up into foliage and controls insects by contact and ingestion.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Actara Insecticide label, EPA Reg. No. 100-938 (EPA-stamped, Dec. 3, 2013).” www3.epa.gov/pesticides/chem_search/ppls/000100-00938-20131203.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)