Specification :

Carbaryl

Common name: carbaryl
IUPAC name: 1-naphthyl methylcarbamate
Chemical Abstracts name: 1-naphthalenyl methylcarbamate
CAS RN: [ 63-25-2]

PHYSICAL CHEMISTRY
Composition: Tech. grade is 99% pure. Mol. wt.: 201.2; M.f.: C12H11NO2; Form: Colourless to light tan crystals. M.p.: 142 º C; V.p.: 4.1x 10-2 mPa ( 23.5 º C) ; KOW: logP = 1.85; Henry: 7.39x 10-5 Pa m3 mol-1 ( calc.) S.g./ density: 1.232 ( 20 º C) ; Solubility: In water 120 mg/ l ( 20 º C) . Readily soluble in polar organic solvents. In dimethylformamide, dimethyl sulfoxide 400-450, acetone 200-300, cyclohexanone 200-250, isopropanol 100, xylene 100 ( all in g/ kg, 25 º C) . Stability: Stable under neutral and weakly acidic conditions. Hydrolysed in alkaline media to 1-naphthol; DT50 c. 12 d ( pH 7) , 3.2 h ( pH 9) . Stable to light and heat. F.p.: 193 ° C

APPLICATIONS
Biochemistry: Weak cholinesterase inhibitor.
Mode of action: Insecticide with contact and stomach action, and slight systemic properties. Uses: Control of Lepidoptera, Coleoptera, and other chewing and sucking insects, at 0.25-2.0 kg a.i./ ha, on more than 120 different crops, including vegetables, tree fruit ( including citrus) , mangoes, bananas, strawberries, nuts, vines, olives, okra, cucurbits, peanuts, soya beans, cotton, rice, tobacco, cereals, beet, maize, sorghum, alfalfa, potatoes, ornamentals, forestry, etc. Control of earthworms in turf. Used as a growth regulator for fruit thinning of apples. Also used as an animal ectoparasiticide.
Phytotoxicity: Non-phytotoxic if used as directed. Under certain conditions, some varieties of apple and pear may be injured.
Formulation types: DP; GR; OF; RB; SC; TK; WP.
Compatibility: Incompatible with alkaline materials such as Bordeaux mixture, lime, and lime sulfur.

MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats 264, female rats 500, rabbits 710 mg/ kg.
Skin and eye: Acute percutaneous LD50 for rats > 4000, rabbits > 2000 mg/ kg. Slight eye irritant, mild skin irritant ( rabbits) .
Inhalation: LC50 ( 4 h) for rats 3.28 mg/ l air.
NOEL: ( 2 y) for rats 200 mg/ kg diet.
ADI: 0.003 mg/ kg b.w.
Toxicity class: WHO ( a.i.) II; EPA ( formulation) I ( ' Tercyl' 85WP) , II ( ' Sevin' 80S) , III
EC hazard R40| Xn; R22| N; R50

ECOTOXICOLOGY
Birds: Acute oral LD50 for young mallard ducks > 2179, young pheasants > 2000, Japanese quail 2230, pigeons 1000-3000 mg/ kg.
Fish: LC50 ( 96 h) for rainbow trout 1.3, sheepshead minnow 2.2, bluegill sunfish 10 mg/ l.
Daphnia: LC50 ( 48 h) 0.006 mg/ l.
Algae: EC50 ( 5 d) for Selenastrum capricornutum 1.1 mg/ l.
Other aquatic spp.: LC50 ( 96 h) for mysid shrimp ( Mysidopsis bahia) 0.0057 mg/ l; LC50 ( 48 h) for Eastern oyster ( Crassostrea virginica) 2.7 mg/ l.
Bees: Toxic to bees; LD50 ( topical) 1 g/ bee.
Worms: LC50 ( 28 d ) 106-176 mg/ kg soil.
Other beneficial spp.: Toxic to beneficial insects.

ENVIRONMENTAL FATE
Animals: In mammals, carbaryl does not accumulate in body tissues, but is rapidly metabolised to non-toxic substances, particularly 1-naphthol. This, together with the glucuronic acid conjugate, is eliminated predominantly in the urine and faeces. Metabolism of carbamate insecticides is reviewed.
Plants: Metabolites are 4-hydroxycarbaryl, 5-hydroxycarbaryl and methylol-carbaryl.
Soil/ Environment: Under aerobic conditions, carbaryl at 1 ppm degraded with DT50 7-14 d in a sandy loam and 14-28 d in a clay loam.