Persistence and Accumulation of Fenitrothion Residues in Jack Pine Foliage and Their Effect on the Swaine Jack Pine Sawfly, Neodiprion swainei (Hymenoptera: Diprionidae) 1

Abstract

Fenitrothion persists in jack pine foliage and with repeated annual treatments (275 g/ha) accumulates in needles but not in bark. These residues are associated with high larval mortality of the Swaine jack pine sawfly, Neodiprion swainei , the differences between treated and controls increasing with the number of fenitrothion appliations. The mean cocoon width of survivors and the fecundity of female sawflies were significantly lower on treated foliage. Conifer needles may be micro-sinks for organophosphorus insecticides. Persistent residues may cause unexpected perturbations in the population dynamics of certain non-target fauna.