• Sundaram, K.M.S.
  Chemical Control Research Institute
  

Fenitrothion [0,0-dimethyl-0-(4-nitro-m-totyl) phosphorothioate] is a widely used organophosphorus pesticide because of its low mammlian toxicity and biological selectivity. It has become the major replacement for DDT in protecting Canadian forests against the ravages of spruce budworm. Application of the insecticide by aircraft at an operational dosage of 0.14 to 0.28 kg/ha (2 to 4 oz A.I./acre) in spring, prevented defoliation by the insect pest, without causing serious ecological damage (Buckner 1974). Because of its wide usage in forestry since 1968 (Fettes 1968), extensive research has been stimulated concerning its effect on various nontarget species of fauna inhabiting the forest and exposed to the toxicant. In recent years the loss of honeybees (Apis mellifera L.) due to insecticides applied for forest pest control has become a serious problem (Atkins et al 1970). Information on the effect and hazards of fenitrothion to honeybees applied under operational conditions for budworm control are not readily available. This report embodies the results and observations made in an extensive three-year study program undertaken in 1972 to determine the effect of fenitrothion applied by aircraft at operational levels on honeybees and its residues, if any, in 122 honeybee, pollen, beeswax and honey samples collected from sprayed forest areas in the provinces of Ontario and Quebec.