Pymetrozine
Chemical compound
From Wikipedia, the free encyclopedia
Pymetrozine is an insecticide in the pyridine-azomethine chemical class, primarily utilized for controlling homopteran pests, such as aphids and whiteflies, in agricultural settings.[2][3] It selectively targets the nervous system of sap-feeding insects, causing them to cease feeding soon after ingestion. This unique mechanism limits impact on non-target beneficial insects. Pymetrozine has been extensively used on rice, potato and brassica crops as an alternative to organophosphorus pesticides.[4][5]
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| Names | |
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| IUPAC name
6-methyl-4-[(E)-pyridin-3-ylmethylideneamino]-2,5-dihydro-1,2,4-triazin-3-one | |
| Other names
Pymetrozin, Fulfill, Plenum, Endeavor | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.121.006 |
| EC Number |
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| KEGG | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C10H11N5O | |
| Molar mass | 217.23 g/mol |
| Density | 1.36 g/cm3 |
| Melting point | 217 °C |
| 2.25g/l 20 °C(Ethanol); 290mg/l, 25 °C (Water); <0.001g/l, 20 °C (Hexane) | |
| Hazards | |
| GHS labelling:[1] | |
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| Warning | |
| H332, H351, H361fd, H410, H412 | |
| P201, P273, P280, P301, P308+P313 | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
5820 mg/kg, Oral (Rat); >2000 mg/kg, percutaneous (Rat); >2000 mg/kg, oral (Bobwhite quail) |
LC50 (median concentration) |
>100 mg/l, (96 hr) (Rainbow trout); >5200 ppm, (8 day) (Bobwhite quail) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Mechanism of action
Pymetrozine is a neurotoxic insecticide that selectively affects chordotonal mechanoreceptors present in the legs of sap-feeding insects.[6] It targetes specific ion channels in the nervous system of insects, particularly the transient receptor potential vanilloid (TRPV) channels.[7][3] It is in IRAC group 9B.[8] These channels, which consist of two key protein subunits, play a crucial role in insect sensory signal transduction. When pymetrozine binds to these channels, it alters their activity, leading to increased sensitivity and disruption of normal neuronal signaling. This results in abnormal behavior in target insects. Pymetrozine acts both on the plant's surface and internally, moving through vascular channels in multiple directions. It penetrates leaf tissues and remains effective when applied to either foliage or soil. It does not interfere with plant growth processes, even after leaf-targeted applications.[5][9]
Safety
Pymetrozine can cause cancer according to The Environmental Protection Agency (EPA).[10] Pymetrozine is of low acute toxicity to humans, mammals, birds, aquatic organisms, and bees.[6] It is a respiratory tract irritant and ingestion may affect major organs at high doses. It may cause reproductive or developmental defects.[11]
Ecotoxicity
Pymetrozine has low off-target effects.
The half-life of pymetrozine in water, soil, and rice plants is 2.81, 6.95, and 3.70 days respectively.[12] Nicotinaldehyde (3-PCA) and 4-amino-6-methyl-3-oxo-2,3,4,5-tetrahydro-1,2,4-triazine are the primary photolysis products of pymetrozine.[13] Exposure to 3-PCA has been reported to cause developmental toxicity in zebrafish.[14]
Use
The annual usage of pymetrozine was at least 4.45 × 103 t in China according to its consumption (150 g/ha) and area of rice field (2.97 × 107 ha).[15]