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Thiamethoxam

Adult Bee Toxicity
0.0027 Oral LD50 in µg/bee
Larval Bee Toxicity
Unknown Oral LD50 in µg/bee
Chemical Group
Neonicotinoid
Adult Bee Toxicity
0.0027
Adult Bee Toxicity Group
High
Larval Bee Toxicity
Unknown
Persistence Half-Life (days)
50
Persistence Rating
Medium
Relative Index of Systemic Activity
1.07
Registered Uses (USA)
A wide variety of agricultural uses (>100 different crops) including vegetables, tree fruits, grapes, other fruits, tree nuts, beans, potatoes, corn, soybeans, canola, other oilseed, wheat, oats, barley, other cereal grains, cotton, rice, sugar beets, peanuts, and other crops. Landcape uses include turf, trees, and landscape plantings. Other uses include nursery uses and non-crop uses, including mosquito control.
Use Categories
Agriculture
Nursery
Landscape
Non-crop
Seed Treatment Use
Yes
Seed Treatment Crops

carrot, potato, sugar beet, onion, leafy vegetables, amaranth, lettuce, spinach, corn salad, brassica leafy vegetables, legume vegetables, beans, soybeans, lentils, peas, cucurbit vegetables, cereal grains, barley, buckwheat, corn (field, pop, and sweet), millet, oat, rice, rye, sorghum, teosinte, triticale, wheat, oilseed entire group (including canola, cotton, and sunflower), alfalfa, and peanuts

Further Information

Xylem and phloem-mobile. Data not available for acute oral toxicity to larval European honey bees, but a study of Italian honey bees determined an oral LD50 of 0.118 µg/larva over an 18 day period. Clothianidin is a major degradate of thiamethoxam. In its 2020 proposed interim reregistration decision, U.S. EPA proposed to cancel seed treatment registrations for bulb vegetables.

Toxicity Reference(s)

U.S. Environmental Protection Agency (EPA). 2017. Preliminary Bee Risk Assessment to Support the Registration Review of Clothianidin and Thiamethoxam. 414 pp.

Systemic Reference(s)

U.S. Environmental Protection Agency (EPA). 2020. Clothianidin and Thiamethoxam Proposed Interim Registration Review Decision, Case Numbers 7620 and 7614. 111 pp. Also, Calvo-Agudo, M., J. González-Cabrera, Y. Picó, P. Calatayud-Vernich, A. Urbaneja, M. Dicke, and A Tena. 2019. Neonicotinoids in Excretion Product of Phloem-Feeding Insects Kill Beneficial Insects. Proceedings of the National Academy of Sciences of the United States of America 116(34):16817–16822.

Persistence Reference(s)

U.S. Environmental Protection Agency (EPA). 2017. Preliminary Bee Risk Assessment to Support the Registration Review of Clothianidin and Thiamethoxam. 414 pp.