A biological assessment of Glypta variegata (Hymenoptera: Ichneumonidae) as a parasitoid of Choristoneura rosaceana (Lepidoptera: Tortricidae)

Abstract

In laboratory trials, Glypta variegata, a common endoparasitoid of leafrollers in North America, successfully parasitized first through third instar Choristoneura rosaceana and first to fourth instar Pandemis limitata. Significantly more second instar C. rosaceana were parasitized when temperatures fluctuated between 30.3 and 12.0°C (16 L:8 D) than when temperatures fluctuated between 17.5 and 4.0°C (12 L:12 D), similar to fall conditions in southern British Columbia, Canada. Under the warmer simulated summer conditions, an average female wasp began to parasitize C. rosaceana 8 days post-emergence (range: 4–16 days), lived 31 days (range: 24–37 days) and successfully parasitized 28 larvae (range: 1–89). When parasitized, C. rosaceana larvae consumed less food in their last two instars than did unparasitized female larvae.

Keywords:

• Obliquebanded leafroller
• three-lined leafroller
• host feeding
• endoparasitoid

Acknowledgments

This research was funded by the British Columbia Fruit Grower's Association, British Columbia Investment Agriculture Foundation, the Industrial Research Assistance Program and Agriculture and Agri-Food Canada.