NOTES ON THE BIOLOGY OF THE APPLE RUST MITE, ACULUS SCHLECHTENDALI (PROSTIGMATA: ERIOPHYOIDAE), AND ITS DENSITY ON SEVERAL CULTIVARS OF APPLE IN NOVA SCOTIA

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Abstract
The apple rust mite, Aculus schlechtendali (Nal.), is active on the apple leaves from late May until early August and passes through three generations as indicated by the peak numbers of eggs. This species overwinters as deutogynes under bud scales and crevices in the bark. During the latter part of May the deutogynes lay eggs that develop into first generation primaries, followed by a second generation the latter part of June. Eggs laid by the second generation primaries produce the overwintering deutogynes. Injury to the leaves, mainly bronzing to the ventral surfaces, becomes noticeable early in July. The numbers of A. schlechtendali varied between cultivars within orchards. The differences were not consistent between orchards.