Performance of potential European biological control agents of Vincetoxicum spp. with notes on their distribution

Abstract

Exploratory surveys were conducted in Europe to locate potential biological control agents of Vincetoxicum nigrum and Vincetoxicum rossicum and to collect known specialist herbivores of Vincetoxicum hirundinaria (Abrostola asclepiadis, Chrysolina a. asclepiadis, Eumolpus asclepiadeus and Euphranta connexa). Development of the most abundant herbivores found attacking leaves, roots, and developing seeds was evaluated in the laboratory on three Vincetoxicum spp. Field surveys revealed that the highest diversity of herbivores was associated with the abundant and widespread V. hirundinaria. No new herbivores were reported from V. hirundinaria or V. nigrum, but the leaf-feeding noctuid Hypena opulenta was recorded for the first time attacking V. rossicum and V. scandens in Ukraine. Based upon larval survival and development and adult fecundity, the leaf feeders A. asclepiadis, C. a. asclepiadis, and H. opulenta, perform better on V. nigrum and V. rossicum than on V. hirundinaria. Larval performance of the root feeder E. asclepiadeus followed a similar pattern, but adult fecundity of this insect did not vary among host plant species. Immature development time of the pre-dispersal seed feeder E. connexa is similar among hosts, but larvae grow larger on V. nigrum and V. hirundinaria than on V. rossicum. All herbivores are promising biological control agents of Vincetoxicum in North America and we have prioritized host range testing with H. opulenta and E. asclepiadeus.