Observations on the life-history traits of the North American parasitoid Phasgonophora sulcata Westwood (Hymenoptera: Chalcididae) attacking Agrilus planipennis (Coleoptera: Buprestidae) in Ontario, Canada

Abstract

AbstractUnder laboratory and field conditions in Ontario, Canada, we explored the natural history of Phasgonophora sulcata Westwood (Hymenoptera: Chalcididae), an indigenous solitary endoparasitoid of Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) in North America. Adult P. sulcata emergence was ~20.2–23.9 days after host emergence at 21°C, with P. sulcata females emerging an ~5.4–5.8 days before males. Females also represented 61.8 and 67.0% of emerging adults in the two years sampled. Mean adult longevities for males and females of P. sulcata were 23.8±1.10 and 28.9±1.11 days at 21°C, respectively. Mean potential fecundity of P. sulcata at emergence was 55.7±2.9 eggs per female. Based on adult emergence, parasitism at two sites varied from 11.7% to 34.4%. Adult parasitoids were first observed in the field in early June, with peak capture occurring in late June. Parasitism rates in A. planipennis-infested ash trees was not affected by tree height below 360 cm, whereas parasitism was not observed at heights>360 cm. Our results suggest that although mass rearing will be challenging, observed parasitism rates in conjunction with temporal and spatial synchrony indicate that indigenous P. sulcata may be an important source of mortality for A. planipennis populations.