Oidaematophorus monodactylus (L.) and Bedellia somnulentella (Zeller): two potential biological control agents of hedge bindweed in southwestern Virginia

Oidaematophorus monodactylus (L.) is a plume moth commonly found feeding on hedge bindweed (Convolvulus sepium L.) in southwestern Virginia. Females maintained at 23.9 + 1°C laid an average of 173 eggs, 61% viable, during a 10-day oviposition period. Average larval leaf consumption was 13 cm² at 18.3°C, increasing to 16 cm² at 29.4°C; over 60% was consumed by the last instar. Mean development period from egg to adult was 28.3 days at 23.9°C.

O. monodactylus completely defoliated a hedge bindweed plant which was infested at the rate of 5 larvae per leaf in greenhouse cage experiments, and caused a significant decrease in the mean percentage of leaf and shoot production as well as total plant length with infestations of 3 larvae per leaf in field cages. This indicated that inundative releases of late instars in early June could reduce the growth rate and seed production of hedge bindweed plants. An estimate of the initial direct cost of rearing 10,000 third instars for a June release totaled a little less than $8,000; of which 30% are non-recurring costs.

A second insect feeding on hedge bindweed is the leaf miner, Bedellia somnulentella (Zeller), which can be found in southwestern Virginia from September through October. Females maintained at 23.9 ± 2°C laid an average of 169 eggs, most of them within the first 8 days of oviposition. The highest rate of pupation was at 23.9°C (98.0), but only 4.6% pupated at 29.4°C. Less than 5% of field collected larvae were parasitized by Apanteles bedelliae Vier.