Invasive Species

Non-native plants and animals that are introduced into North America typically come without the natural enemies that keep them in check in their native habitats. Freed from natural controls, alien species reproduce and spread. We are addressing this issue by attempting to reduce the risk from purposeful plant introductions, and by working on biological control of select insect and weed problems.

Identification and Replacement of Invasive Ornamentals

Of the thousands of species of exotic plants that were introduced and distributed in this country for horticultural or agronomic uses over the past 300 years, several species are now widely regarded as pests. Well-known examples include kudzu, crabgrass, dandelion, barberry, and purple loosestrife. Some important ornamental plants (Norway maple, winged euonymous, Korean dogwood) have invasive tendencies, which may present problems in minimally managed landscapes. Our research focus is to identify invasive species and select, evaluate, and promote alternative species suitable for the nursery and landscape industries.

Our research and outreach goals in this program are to

  • evaluate existing and potential new ornamental plant introductions for potential invasiveness
  • develop ornamental plants which do not reproduce and spread in the landscape, and
  • develop and promote plants which are non-invasive alternatives to current invasive ornamentals

Biological Control of Invasive Species

Of ~ 1,700 introduced insects in this country, over half are identified as pests. The 300 species of invasive plants in North America have already infested 100 million acres and infest another 3 million acres per year (about 4.5 times the land area of R.I.). Combined with the other exotic invasive animals (such as zebra mussels) these invasive species cause ~$123 billion in damages annually in the USA. In many cases these problems can be solved by “reacquainting” these “pests” with effective natural enemies in a deliberate process called “Classical Biological Control.”

Our USDA-approved primary quarantine laboratory—the only university quarantinelab in the Northeast— allows us to import and study potential biological control agents that do not exist elsewhere in North America. We concentrate on invasive insects and plants, particularly those of consequence to landscape plants in the Northeast. We are currently working on birch leafminer, hemlock woolly adelgid, lily leaf beetle, purple loosestrife, Cypress spurge, andPhragmites australis (common reed). The goal of this research is to provide permanent control of key insect and weed pests and in the process to advance the science of biological control.