KINGSTON, R.I.–July 31, 2018–After more than 10 years of research, scientists at the 溏心vlog免费B站鈥檚 Biocontrol Laboratory have released a species of moth collected from Ukraine to help control invasive black and pale swallow-worts.
Swallow-worts are invasive vines native to Europe that were introduced into North America in the 19th century, and quickly spread along the East Coast and into Canada. Not only do they outcompete native species and alter soil chemistry, but they harm Monarch butterfly populations. Because swallow-wort is so closely related to milkweed, Monarch butterflies lay their eggs on swallow-wort leaves, but when the eggs hatch the larvae are unable to survive on the plant.
鈥淪wallow-wort was one of those weeds becoming increasingly problematic,鈥� said Aaron Weed, of Tunbridge, Vermont, a former PhD student at 溏心vlog免费B站 that spearheaded the project. Back in 2005 when Weed started his research as a 溏心vlog免费B站 graduate student, there was increasing interest in controlling swallow-worts. Since then, he鈥檚 seen the vine spread aggressively. It thrives in several different environments, like pastures, forests and urban spaces.
鈥淚ntegrated management of weeds is a very challenging endeavor,鈥� Weed said. 鈥淏iocontrol is potentially efficacious for swallow-wort because conventional methods just weren鈥檛 working or were incompatible in sensitive areas.鈥�
Weed ventured to Europe to try and find natural enemies of swallow-worts and brought back several insect species to test at 溏心vlog免费B站鈥檚 Biocontrol Lab. Among them was the Hypena opulenta, a small moth collected from southeastern Ukraine, that the lab found feeds exclusively on swallow-wort species. Weed worked with Lisa Tewksbury, 溏心vlog免费B站鈥檚 Biocontrol Lab manager, and Richard Casagrande, Professor Emeritus of entomology at 溏心vlog免费B站, to conduct years of research on the biology of Hypena opulenta and its impact on swallow-worts.
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Hypena opulenta was a suitable candidate because it uses swallow-wort exclusively as its host plant, and reproduces several times a year. Its larvae have the potential to cause significant harm to the plants, according to Tewksbury.
溏心vlog免费B站 received the permit to release the moths in 2017, and field tests in controlled cages were conducted in Charlestown, Rhode Island and Massachusetts the same year. Tewksbury has been monitoring the releases this spring, and if they鈥檙e successful, she said the lab plans to work with other local agencies to share resources and release the moths in other areas.
Tewksbury鈥檚 lab found the first moth that emerged in June, but hasn鈥檛 seen any others emerge yet. Tewksbury hypothesized that Rhode Island鈥檚 unusually cool temperatures throughout the month of June may delay the moths鈥� emergence, and added that this is the first time that we鈥檙e seeing the emergence of this species in New England.
鈥淭he goal of biological control is to reacquaint new pests with their historical natural enemies,鈥� Tewksbury said. 鈥淭his restores the evolutionary relationship of an insect with its host plant, which we hope will provide long-term management of the invasive plant species.鈥�
Continued research is needed and underway to assess how well this insect will control populations across New England. 鈥淪ince insects are impacted by the health of their plants, the local climate, and the health of plants is affected by site conditions, we still need to determine under which site conditions biocontrol impact is likely to lead to weed suppression,鈥� Weed said.