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During an investigation into the importance of fungal disease as a factor in the control of orchard pests throughout the Annapolis Valley, Nova Scotia, the haemocoele of large numbers of Macrosiphum pisi (Kaltenbach) was found to be infected with a fungal growth that resulted in death. This fungus was identified from mounted specimens as Empusa (= Entomophthora) aphidis Hoffman.
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D. M. MacLeod (1955) studied this question.
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