IDENTIFICATION
Common name: Imidacloprid
Other name: imidacloprid (BSI, dj`aft E-ISO); imidaclopride ((m) F-ISO)
Iupac name: q-(6-chloro-3-pyridylmethyl)-N-nitr~imidaz~lidin-2-ylideneamine
Chemical abstracts name: 1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidinimine
Type: Insecticide for Agriculture
CAS RN: [138261-41-3]
M.F.: C9H10ClN5O2
Mol Wt: 255.7
PHYSICAL CHEMISTRY
Form (appearance): Colourless crystals, with a weak characteristic odour
M.P.: 144℃
V.P.: 4 × 10-7 mPa (20℃); 9 × 10-7 mPa (25℃)
S.G.: 1.54 (23℃)
Solubility.: In water 0.61 g/l (20℃). In dichloromethane 55, isopropanol 1.2, toluene 0.68, n-hexane <0.1 (all in g/l, 20℃).
Stability: Stable to hydrolysis at pH 5-11.
Henry: 2 × 10-10 Pa m3 mol-1 (20℃, calc.)
KowlogP: 0.57 (21℃)
APPLICATION
Formulation types: DP; FS; GR; SC; SL; WG; WP; WS.
Biochemistry: Acts as an antagonist by binding to postsynaptic nicotinic receptors in the insect central nervous system.
Mode of action: Systemic insecticide with translaminar activity and with contact and stomach action. Readily taken up by the plant and further distributed acropetally, with good root-systemic action.
Uses: Control of sucking insects, including rice-, leaf-and planthoppers, aphids, thrips and whitefly. Also effective against soil insects, termites and some species of biting insects, such as rice water weevil and Colorado beetle. Has no effect on nematodes and spider mites. Used as a seed dressing, as soil treatment and as foliar treatment in different crops, e.g. rice, cotton, cereals, maize, sugar beet, potatoes, vegetables, citrus fruit, pome fruit and stone fruit.
MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for male and female rats c. 450 mg/kg.
Skin and eye: Acute percutaneous LD50 (24 h) for rats >5000 mg/kg. Non-irritating to eyes and skin (rabbits). Not a skin sensitiser.
Inhalation: LC50 (4 h) for rats >5323 mg/m3 dust, 69 mg/m3 air (aerosol).
Noel: (2 y) for male rats 100, female rats 300, mice 330 mg/kg diet; (52 w) for dogs 500 mg/kg diet.
ADI: 0.057 mg/kg b.w.
Other Not mutagenic or teratogenic.
Toxicity: WHO (a.i.) II; EPA (formulation) II
ECOTOXICOLOGY
Birds: Acute oral LD50 for Japanese quail 31, bobwhite quail 152 mg/kg. Dietary LC50 (5 d) for bobwhite quail 2225. mallard ducks >5000 mg/kg.
Fish: LC50 (96 h) for golden orfe 237, rainbow trout 211 mg/l.
Daphnia: LC50 (48 h) 85 mg/l.
Algae: ErC50 for Pseudokirchnerietla subcapitata >100 mg/l.
Worms: Algae ErC50 for Pseudokirchnerietla subcapitata >100 mg/l. LC50 for EisenJa foefida 10.7 mg/kg dry soil.
Bees: Harmful to honeybees by direct contact, but no problems expected when not sprayed into flowering crop or when used as a seed treatment.
ENVIRONMENTAL FATE
Animals: After oral administration of methylene-14C- and 4,5 imidazolidine 14C labelled imidacloprid to rats, the radioactivity was quickly and almost completely absorbed from the gastro-intestina[ tract and quickly eliminated (96% within 48 hours, mainly via the urine). Only c. 15% was eliminated as unchanged parent compound: the most important metabolic steps were hydroxylatJon at the Jmidazolidine ring, hydrolysis to 6chloronicotinic acid, loss of the nitro group with formation of the guanidine and conjugation of the 6-chtoronicotinic acid with glycine. All metabolites found in the edible organs and tissues of farm animals contained the 6-chloronicotinic acid moiety. Imidacloprid is also quickly largely eliminated from hens and goats. Plants Metabolism was investigated on rice (after soil treatment), maize (seed treatment), potatoes (granule or spray application), aubergines (granules) and tomatoes (spray treatment). In all cases, imidacloprid is metabolised by loss of the nitro group, hydroxylation at the imidazolidine ring, hydrolysis to 6-chloronicotinic acid and formation of conjugates; all metabolites contained the 6-chloropyridinylmethylene moiety.
Soil/Environment: In lab. studies, the most important metabolic steps were oxidation at the imidazolidine ring, reduction or loss of the nitro group, hydrolysis to 6-chtoronicotinic acid and mineralisation; these processes were strongly accelerated by vegetation, tmidacloprid shows a medium adsorption to soil. Column leaching tests (with prior ageing) with a.i. and various formulations showed that imidacloprid and soil metabolites are to be classified as immobile; leaching into deeper soil layers is not to be expected if imidacioprid is used as recommended. Stable to hydrolysis under sterile conditions (under exclusion of light). Environmental DT50 c. 4 h (calc., based on tests of direct photolysis in aqueous solutions). Besides sunlight, the microbial activity of a water/sediment system is an important factor for the degradation of imidactoprid. |
