Pesticides >> Insecticides >> Diafenthiuron
Common name diafenthiuron (BSI, draft E-ISO)
IUPAC name 1-tert-butyl-3-(2,6-di-isopropyl-4-phenoxyphenyl)thiourea
Chemical Abstracts name N-[2,6-bis(1-methylethyl)-4-phenoxyphenyl]-N'-(1,1-dimethylethyl)thiourea
CAS RN [80060-09-9] Development codes CGA 106 630 (Ciba-Geigy);
Biochemistry Converted by light, or in vivo, to the corresponding
carbodiimide, which is an inhibitor of mitochondrial respiration.
Mode of action Insecticide and acaricide which kills larvae, nymphs
and adults by contact and/or stomach action; also shows some ovicidal
action. See J. Drabek et al. (Recent Adv. Chem. Insect Control II,
1990, p. 170). Uses Insecticide and acaricide effective against
phytophagous mites (Tetranychidae, Tarsonemidae), Aleyrodidae, Aphididae
and Jassidae on cotton, various field and fruit crops, ornamentals
and vegetables. Also controls some leaf-feeding pests in cole crops
(Plutella xylostella), soya beans (Anticarsia gemmatalis) and cotton
(Alabama argillacea). Applied at 300-500 g/ha. Is safe on adults
of all beneficial groups (Anthocoridae, Coccinellidae, Miridae)
and on adults and immature stages of predatory mites (Amblyseius
andersoni, Typhlodromus pyri), spiders (Erigonidae, Lycosidae),
and Chrysopa carnea. Non-selective to immature stages of Heteroptera
(Anthocoridae, Miridae). Compatible with the biological control
of Aleyrodidae and mites in glasshouses. Formulation types SC; WP.
Selected tradenames: 'Pegasus' (Syngenta); 'Polo' (Syngenta); mixtures:
'Dicare' (+ fenoxycarb) (Syngenta)
Product analysis by glc. Residues determined by glc. Details available
Oral Acute oral LD50 for rats 2068 mg/kg. Skin and eye Acute percutaneous
LD50 for rats >2000 mg/kg. Non-irritant to eyes and skin (rats).
Inhalation LC50 (4 h) for rats 0.558 mg/l air. NOEL (90 d) for rats
4, dogs 1.5 mg/kg b.w. daily. ADI 0.003 mg/kg b.w. Toxicity class
WHO (a.i.) III EC hazard (R21/22, R23, R48)
Birds Acute oral LD50 for bobwhite quail and mallard ducks >1500
mg/kg. Dietary LC50 (8 d) for bobwhite quail and mallard ducks >1500
mg/kg. No acute hazard under field conditions. Fish LC50 (96 h)
for carp 0.0038, rainbow trout 0.0007, bluegill sunfish 0.0013 mg/l.
Because of rapid degradation to non-toxic metabolites, there is
no significant hazard under field conditions. Daphnia LC50 (48 h)
<0.5 mg/l. Algae Non toxic. Bees Toxic to honeybees; LD50 (48
h) (oral) 2.1 mg/bee; (contact) 1.5 mg/bee. No significant hazard
under field conditions. Worms No adverse effects on earthworms.
Animals Study of the absorption, distribution and excretion in rats
demonstrated that the major portion of the dose was excreted with
the faeces. The compound is degraded to yield its corresponding
carbodiimide, which, in turn, reacts with nucleophiles like water
and fatty acids to form urea and fatty acid derivatives. Plants
In plants, diafenthiuron shows a complex metabolism pattern in all
crops investigated, i.e. cotton, tomatoes and apples. Uptake of
residue activity by plants from soil is low. Soil/Environment Diafenthiuron
and its main metabolites show a strong sorptivity to soil particles.
Degradation in soils proceeds rapidly: DT50 <1 h to 1.4 d.