Diazinon birds

Diazinon Acute oral LD50 Rat 450 Birds (mean 4 species) 4.5 100... 

The organophosphorons insecticides dimethoate and diazinon are mnch more toxic to insects (e.g., housefly) than they are to the rat or other mammals. A major factor responsible for this is rapid detoxication of the active oxon forms of these insecticides by A-esterases of mammals. Insects in general appear to have no A-esterase activity or, at best, low A-esterase activity (some earlier stndies confnsed A-esterase activity with B-esterase activity) (Walker 1994b). Diazinon also shows marked selectivity between birds and mammals, which has been explained on the gronnds of rapid detoxication by A-esterase in mammals, an activity that is absent from the blood of most species of birds (see Section 23.23). The related OP insecticides pirimiphos methyl and pirimiphos ethyl show similar selectivity between birds and mammals. Pyrethroid insecticides are highly selective between insects and mammals, and this has been attributed to faster metabolic detoxication by mammals and greater sensitivity of target (Na+ channel) in insects. 

LD50S of diazinon and dimethoate to four species of birds have been expressed as a mean to facilitate comparison with data for the rat. 

Acute oral toxicity of diazinon to birds and mammals... 

Table 16.4 Acute Oral Toxicity of Diazinon to Birds and Mammals (All values shown are in milligrams of diazinon/kg body weight fatal to 50% after a single oral dose.)...

Stone, W.B. 1980. Bird deaths caused by pesticides used on turfgrass. N.Y. State Turf grass Conf. Proc. 4 58-62. Stone, W.B. and P.B. Gradoni. 1985. Wildlife mortality related to use of the pesticide diazinon. Northeast. Environ. Sci. 4 30-38. 

Diazinon 900-1800 Non systemic organophosphate insecticide Moderate Birds Fish Insects... 

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