Thiamethoxam チアメトキサム
Neonicotinoids: Bind to the receptors in insect nerves (nicotinic acetylcholine receptors). Many are taken up through roots or leaves and spread through the whole crop (systemic).
In Japan
- Registration
- Registered as a pesticide (first registered August 15, 2000). 23 formulated products contain it.
- Main registered crops
- rice (paddy), cucumber, eggplant, cabbage, tomato, citrus and others (99 crop names in the registered uses)
- Toxicity class
- Active ingredient: Ordinary substanceClasses of the 23 formulated products (diluted products sold): ordinary substance 23Classes under Japan's Poisonous and Deleterious Substances Control Act.
- ADI (acceptable daily intake)
- 0.012 mg per kg of body weight per day
- ARfD (acute reference dose)
- 0.5 mg per kg of body weight
- Evaluation
- Food Safety Commission of Japan, June 10, 2026
ADI: the amount considered to have no effect on health even if eaten every day for a lifetime. ARfD: the amount considered to have no effect on health when eaten at one time (within 24 hours). Both are set by the Food Safety Commission of Japan, mainly from animal studies.
In Japan's national residue testing (fiscal 2024)
| Produce | Detected / tested | Detection rate | Over the limit |
|---|---|---|---|
| DomesticNo. 15 by detection rate | 66 / 3,236 | 2.0% | 0 |
| Imported | 368 / 12,040 | 3.1% | 17 |
Found in domestic foods: strawberry, persimmon, cucumber (including gherkin), kyona (mizuna), komatsuna (Japanese mustard spinach), taro-type crops (including yatsugashira taro), shungiku (garland chrysanthemum), eggplant, carrot, Welsh onion (including leek), napa cabbage, grape and others (max. 0.43 ppm)
Found in imported foods: cherry (including cherries), kabocha pumpkin (including squash), burdock root, sesame seeds, other nightshade (Solanaceae) vegetables, other herbs, other vegetables, onion, daikon-type roots (including radish), carrot, garlic, Welsh onion (including leek) and others (max. 7.0 ppm)
Tests are counted as pesticide × sample. Any detection counts as “detected” — it does not mean the limit was exceeded. For pesticides outside the top 20, figures are summed from the food-by-food tables of the full report.
In the Consumer Affairs Agency's market basket survey (fiscal 2024; the amount actually taken in from everyday meals), intake was 0.009–0.162% of the ADI.
Evaluations abroad
- WHO acute toxicity class
- II (Moderately hazardous), LD50 871 mg/kgBased on the toxicity of the undiluted active ingredient given once, mainly to rats by mouth (LD50 = the dose that kills half; the smaller, the stronger the acute toxicity). It is not an assessment of the safety of residues in food.
- EU
- Not approved in the EU (approval ended April 2019)EU ADI: 0.026 mg/kg bw/day; ARfD: 0.5 mg/kg bw
- IARC (carcinogenicity)
- No matching entry in the IARC list (not evaluated or out of scope, including Group 3)
Good to know
- In 2018, the EU banned outdoor use of three active ingredients: clothianidin, imidacloprid and thiamethoxam (because of their effects on honeybees; use is allowed only inside greenhouses).
- In the MAFF survey of honeybee poisoning incidents (fiscal 2013–2015), among the insecticides found in honeybees that died during the rice stink bug control season, this active ingredient accounted for 1 (38 in total, with overlaps).
Related explainers
Sources
- FAMIC (Food and Agricultural Materials Inspection Center), pesticide registration information (as of Sept. 30, 2026) (Japanese)
- Food Safety Commission of Japan, risk assessment report on Thiamethoxam (June 10, 2026) (Japanese)
- MHLW, results of pesticide residue testing in foods, fiscal 2024 (Japanese)
- Consumer Affairs Agency, daily intake survey of pesticide residues in foods, fiscal 2024 (Japanese)
- WHO Recommended Classification of Pesticides by Hazard 2019
- EU Pesticides Database (Thiamethoxam)
Last checked 2026-10-01. Registrations and evaluations change over time. This page is a translation of our Japanese page; if they differ, the Japanese page is the reference.