Thiamethoxam

Thiamethoxam

噻虫嗪

(EZ)-3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro)amine

3-[(2-chloro-5-thiazolyl)methyl]tetrahydro-5-methyl-N-nitro-4H-1,3,5-oxadiazin-4-imine

153719-23-4

C₈H₁₀ClN₅O₃S

Insecticides > Thiazole insecticides
Insecticides > Neonicotinoid insecticides

Insecticide

Thiamethoxam is highly plant systemic. The product is rapidly taken up by seeds, roots, stems and foliage, and translocated acropetally in the xylem. The metabolic pathways for thiamethoxam are similar in corn, cucumbers, pears and rotational crops, where it is metabolised slowly resulting in a long period of bioavailability. Thiamethoxam's high water-solubility renders it more effective than other neonicotinoids under dry conditions. Rainfastness is not a problem, however, because of its rapid uptake by plants. This also offers protection against the transmission of viruses by sucking pests. Thiamethoxam is a contact and stomach poison. It is particularly effective as a seed treatment against soil-dwelling and early season pests. As a seed treatment, the product can be used on a greater number of crops (including cereals) against a broader range of pests. It has residual activity lasting up to 90 days, which may obviate the need to use additional soil-applied insecticides.

In field trials, using seed treatments and applications to seedling boxes, furrows, tree trunks and foliage, thiamethoxam gave similar or better control of pests than other neonicotinoids and established insecticides, usually at lower application rates. The product is safe to predatory mites but has some toxicity to beneficial species such as bees. Flexibility in the mode of application of the product, however, means that it can still be recommended for use in IPM schemes.

Thiamethoxam at 60 g ai/ha was found to provide moderate control of soil pests such as springtails, symphylids, wireworms and millipedes; this was improved on addition of tefluthrin, as was found for imidacloprid. The product did not provide effective control of leatherjackets.

Trials using the product Cruiser 350 FS have shown it to be effective against the corn weevil (Tanymecus dilaticollis) on maize and sunflower. In studies carried out by Mycogen to assess early-season insect protection in sunflower crops, Cruiser treatment achieved improved plant stand and vigor (15% increase in the level of stand establishment and ca 2,500-3,000 additional plants/acre). The product protects the germinating seed and young sunflower plants from damage caused by wireworm, pale striped flea beetle (Systena blanda) and sunflower beetles (Zygogramma esclamationis). Cruiser offers good early-season insect protection for early stand establishment particularly in minimum-till or no-till systems.

In a study conducted at the university of Kansas (ESA 2004), thiamethoxam achieved good control of adult beetle pests of stored seed corn at low rates (up to 4 ppm) when maize weevil (Sitophilus zeamais), sawtoothed grain beetle (Oryzaephilus surinamensis) and red flour beetle (Tribolium castaneum) were treated for 1-6 days at varying temperatures. 58-90% mortality of the most susceptible beetle species, the maize weevil, was achieved with 0.5 ppm thiamethoxam at all exposure times and temperatures.

In sorghum, Cruiser protects the crop from soil and foliar pests including chinch bug (Blissus leucopterus), greenbug (Schizaphis graminum), corn leaf aphid (Rhopalosiphum maidis), seed corn maggot (Delia platura) and yellow sugar cane aphid (Sipha flava).

The efficacy of thiamethoxam was evaluated as a seed treatment for controlling European corn borer, Ostrinia nubilalis (Hübner) and Indianmeal moth, Plodia interpunctella (Hübner) larvae in stored grain (J Econ Entomol, 2003). At 22-26°C, all fifth instar European corn borers were killed after two or four days of exposure to corn treated with 250 and 500 ppm thiamethoxam, respectively. Mortality of larvae exposed for two and four days on corn treated with 6.3-937.5 ppm imidacloprid did not exceed 48% at any concentration. At 29°C, all non-diapausing fifth instars were killed after 3, 4 and 6 days exposure to 400, 300 and 200 ppm thiamethoxam, respectively, while survival increased at successively lower concentrations of 100, 50, 25 and 12.5 ppm. All second and third instar Indianmeal moth larvae died after a 5 days exposure period to corn treated with thiamethoxam at 50 ppm or higher. As the larvae aged, higher concentrations and longer exposure periods were required to give 100% mortality of each larval instar. Similar results were obtained when larval Indianmeal moths were exposed on corn treated with imidacloprid, or on sorghum treated with thiamethoxam. Mature wandering phase fifth instars were the most tolerant larval stage.

Thiamethoxam could provide an alternative to established products such as carbofuran which faces concerns over its high mammalian toxicity and emerging pest resistance.

On green beans in the US, Cruiser provides control of leafhoppers, bean leaf beetle (Cerotoma trifurcata), aphids and wireworms.

The greenhouse whitefly has recently become a major pest on strawberries in California. Neonicotinoids such as thiamethoxam and insect growth regulators were tested against this pest on strawberries under greenhouse and field conditions. Results showed that neonicotinoids such as thiamethoxam are very effective against whiteflies.

CropUses:
cabbages, citrus, cocoa, coffee, cotton, cucurbits, vegetables, lettuces, ornamentals, peppers, pome fruits, popcorn, potatoes, rice, stone fruits, tobacco, tomatoes, vines, brassicas, cereals, cotton, legumes, maize, oilseed rape, peanuts, potatoes, rice, sorghum, sugar beet, sunflowers, sweet corn Foliar and soil treatments: citrus, cole crops, cotton, deciduous, leafy and fruity vegetables, potatoes, rice, soybeans, tobacco.
Seed treatment: beans, cereals, cotton, maize, oilseed rape, peas, potatoes, rice, sorghum, sugar beets, sunflower.

Foliar/Soil application	10-200 g ai/ha
Seed treatment	39 g ai/100 kg seed on wheat, 199 g ai/100 kg seed on sorghum, 299 g ai/100 kg seed on cotton

control of aphids, whitefly, thrips, ricehoppers, ricebugs, mealybugs, white grubs, Colorado potato beetle, flea beetles, wireworms, ground beetles, leaf miners and some lepidopterous species.

FS = Flowable concentrate for seed treatment
GR = Granule
SC = Suspension concentrate (=flowable concentrate)
WG = Water dispersible granules
WP = Wettable powder
WS = Water dispers

Thiamethoxam+lambda-cyhalothrin
Thiamethoxam+abamectin
Thiamethoxam+azoxystrobin+fludioxonil+metalaxyl-M
Thiamethoxam+chlorantraniliprole
Thiamethoxam+difenoconazole
Thiamethoxam+difenoconazole+fludioxonil+metalaxyl-M
Thiamethoxam+fludioxonil+metalaxyl-M
Thiamethoxam+metalaxyl-M
Thiamethoxam+abamectin+azoxystrobin
Thiamethoxam+abamectin+azoxystrobin+fludioxonil+metalaxyl-M
Thiamethoxam+difenoconazole+metalaxyl-M
Thiamethoxam+fludioxonil
Thiamethoxam+tefluthrin
Azoxystrobin+fludioxonil+metalaxyl-M+thiabendazole+thiamethoxam
Spinosad+thiamethoxam+R-metalaxyl+fludioxonil+azoxystrobin
Fludioxonil+difenoconazole+thiamethoxam
Thiamethoxam+fludioxonil+metalaxyl-M
thiamethoxam+difenoconazole+metalaxyl-M+sedaxane+fludioxonil
Cyantraniliprole+Thiamethoxam
Pymetrozine+Thiamethoxam
Pasteuria nishizawae+thiamethoxam+fludioxonil+mefenoxam+sedaxane
thiamethoxam+fludioxonil+azoxystrobin+mefenoxam
Bifetnthrin·Thiamethoxam
Bifenthrin+Thiamethoxam
ABAMECTIN+THIAMETHOXAM+DIFENOCONAZOLE
Tebuconazole+Thiamethoxam
Thiamethoxam+Thiram+Carboxin
Thiamethoxam+Thiram+Carboxin
Emamectin benzoate+Thiamethoxam
Thiamethoxam+Indoxacarb
Pyraclostrobin+Carboxin+Thiamethoxam
Thiamethoxam+Cyromazine
Fenaminstrobin+Difenoconazole+Thiamethoxam
Carbosulfan+Thiamethoxam
Thiamethoxam+Bisultap
Monosultap+Thiamethoxam
Thifluzamide+Thiamethoxam
Flonicamid+Thiamethoxam
Chlorfenapyr+Thiamethoxam
Pyriproxyfen+Thiamethoxam
Azoxystrobin+Prochloraz+Thiamethoxam
Nitenpyram+Thiamethoxam
Spirotetramat+Thiamethoxam
Dinotefuran+Thiamethoxam
Azoxystrobin+Thiamethoxam+Thifluzamide
Premix Parters: bentazone flumetsulam; chlorimuron-ethyl; metsulfuron-methyl tribenuron-methyl; rimsulfuron; tribenuron-methyl;

Molecular weight:291.7; Physical form:Crystalline powder. Melting point:139.1 °C; Vapour pressure:6.6 ×10-6 mPa (25 °C); Henry constant:4.70 × 10-10 Pa m3 mol-1 ( calc.); Partition coefficient(n-octanol and water):logP = -0.13 (25 °C); Solubility:In water 4.1 g/l (25 °C).;

Oral:Acute oral LD₅₀ for rats 1563 mg/kg. Percutaneous:Acute percutaneous LD₅₀ for rats >2000 mg/kg. Non-irritating to skin and eyes (rabbits); not a skin sensitiser (guinea pigs). Inhalation: LC₅₀ (4 h) for rats >3720 mg/m³. ADI:( JECFA) 0.1 mg/kg b.w. [1997].

Ecotoxicology:
 Algae: EC₅₀ (96 h) for green algae >100 mg/l.Bees: LD₅₀ for honeybees (contact) 0.024 µg/bee.Birds:Acute oral LD₅₀ for bobwhite quail 1552, mallard ducks 576 mg/kg. Dietary LC₅₀ for bobwhite quail and mallard ducks >5200 mg/kg.Daphnia: EC₅₀ (48 h) >100 mg/l.Fish: LC₅₀ (96 h) for rainbow trout >100, bluegill sunfish >114, sheepshead minnow >111 mg/l.Worms: LC₅₀ (14 d) for Eisenia foetida >1000 mg/kg soil.Other aquatic spp.: LC₅₀ (96 h) for mysid shrimp 6.9 mg/l; EC₅₀ (96 h) for Eastern oyster >119 mg/l. 

Environmental fate: 
Animals:Quickly and completely absorbed, rapidly distributed in the body and rapidly eliminated. The toxicokinetics and metabolism are not influenced by the route of administration, the dose level, pre-treatment, the site of label or the sex of animals. The majorSoil:Soil DT₅₀ (median) 51 d. Stable in water under acid conditions, hydrolysed under alkaline conditions. Aqueous photolysis occurs rapidly. No bioaccumulation.Plant:Degradation/metabolism has been studied in 6 different crops with soil, foliar and seed treatment application. The qualitative metabolic pattern was similar for all types of applications and for all studied crops.

Mallard duck	LD50 576 mg/kg
Bobwhite quail	LD50 1,552 mg/kg
Rainbow trout [96 h]	LC50 >125 mg/L
Bee [contact]	LD50 0.024 μg/bee
Bluegill sunfish [96 hr]	LC50 >114 mg/L

Fate in :
Thiamethoxam is described by Syngenta as being only 'slightly to moderately toxic' to beneficial species such as bees and safe to predatory mites.

Fate in soil:
Thiamethoxam is degraded primarily by microbial action in soil; it has a median half-life of 51 days. Field trials indicate that the product is moderately to highly mobile in soil.

Fate in aquatic systems:
Thiamethoxam is degraded primarily by photolysis in water although it also undergoes hydrolysis at pH 7.

Signal Word:CAUTION; Hazard Class:III(Slightly hazardous)