Toxicity of foliar residues of phosmet to the apple maggot, <i>Rhagoletis pomonella</i> (Diptera: Tephritidae)

Authors

  • A. B. Mohammad Department of Entomology Oregon State University Corvallis, OR 97331
  • M. T Aliniazee Department of Entomology Oregon State University Corvallis, OR 97331

Abstract

Mortality of apple maggot (AM), Rhagoletis pomonella (Walsh), was determined in the laboratory on spray deposits of phosmet (Irnidan®) applied to apple foliage and fruit at rates of 0.6 and l.2 g active ingredient (AI)/liter (0.5 and I pound [AI]/IOO gallons). Mortality of AM adults was 100% with both rates until 16 days post-treatment. Thereafter, mortality decreased inversely with time. Probit analysis revealed insecticide residual toxicity of 24 days for 95% mortality (ET9S) for both rates, and 51 and 55 days, respectively, for 50% mortality (ETso) at 0.6 and 1.2 g (AI)/1iter. The intercepts and slopes of probit regression were not significantly different for the two rates tested, indicating little difference between their persistence and efficacy against AM adults.

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