Pope_1972_Pest.Sci_3_197

Experiments were carried out in East Africa to determine the effects of single-drop applications of the avicide Queletox (active ingredient fenthion) on the Red-billed Quelea Q. quelea, an important agricultural pest. Birds treated with relatively large amounts of Queletox died within a few hours, as expected. Most of those receiving the smallest lethal doses died 12 to 48 h after treatment. From their terminal fat and muscle condition it was concluded that they died of starvation, despite their apparently healthy appearance following treatment and the easy availability of suitable food. LD50's of 80 and 220 mg/kg were obtained for Queletox applied to the feathers of the back in drops of varying sizes or concentrations, the amount of solvent having an important effect on the toxicity. The possibility is raised of reducing the amounts of Queletox used in control operations against the birds, making them safer and cheaper.