COLD TOLERANCE OF HICKORY SHUCKWORM (LEPIDOPTERA, TORTRICIDAE) LARVAEAND ASSOCIATED PARASITES

Hickory shuckworm larvae, Cydia caryana (Fitch), in pecan shucks, were killed by extended periods of freezing temperature. While storage at -7 degrees C killed 88% of larvae after 32 days of exposure, -18 degre es C killed 85% after only 1 day and 100% by 8 to 16 days of exposure. Larvae exposed to cold temperatures prior to -18 degrees C exposure a ppeared to possess enhanced cold resistance but were still killed afte r 32 days of exposure. Survival of the ichneumonid parasite, Calliephi altes grapholithae (Cresson), which comprised 92% of the total of all parasites emerging from pecan shucks, was not detectably affected by e xposure to cooling (3-5 degrees C) for up to 5 wks. Thereafter, when e mergence began to decrease, about half of the parasites in the extende d cooling treatment were viable for at least 10 wks. Conversely, 3 oth er parasites Phanerotoma fasciata Provancher (Braconidae), Macrocentru s instabilis Muesebeck (Braconidae), and Lixophaga mediocris Aldrich ( Tachinidae), comprised the remaining 8% of total parasite emergence an d survival was severely affected by extended cooling (3-5 degrees C).