EFFECT OF TEMPERATURE ON THE EMERGENCE OF OVERWINTERING PHYLLONORYCTER BLANCARDELLA (LEPIDOPTERA: GRACILLARIIDAE) AND ITS PARASITE APANTELES ORNIGIS (HYMENOPTERA: BRACONIDAE) IN NOVA SCOTIA

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Abstract
Adult emergence of the spotted tentiform leafminer, Phyllonorycter blancardella (F.), and its primary endoparasite, Apanteles ornigis Weed, from overwintering pupae was studied at five constant temperatures. Days to 50% emergence for P. blancardella were 55.4, 24.4, 14.4, 10.8, and 8.3 and for A. ornigis were ∞, 47.8, 25.6, 17.6, and 15.1 at 8°, 12°, 16°, 20°, and 24 °C, respectively. The rate of pupal development was approximately a linear function of temperature for P. blancardella but was nonlinear for A. ornigis. The threshold of development, estimated from the 50% emergence data, was 4.4 ±.33 °C for the host and 9.6 ±.50 °C for the parasite. The development time for the host was approximately one half that for the parasite at temperatures 12°–24 °C. The difference in emergence dates between host and parasite under normal Nova Scotia conditions was predicted to be 35 days. The timing of chemical controls in an integrated pest management program could be predicted from the accumulation of daily development units based on the power function for both species, provided a field study is undertaken to confirm the extrapolation to diurnal temperature regimes.