Invasive Species

New York State defines “invasive species” as follows: (a) non-native to the ecosystem under consideration; and (b) whose introduction causes or is likely to cause economic or environmental harm or harm to human health. According to NYS DEC, invasive species are a threat to our biodiversity and are judged second only to habitat loss. Invasives hail from around the world, and the rate of invasion is increasing at an alarming rate with the increase in international trade.

Invasive species have been problematic in the past and are certainly a problem now, since they threaten our ecosystems, including all natural systems, managed forests, our food supply, including not only agriculture, but also harvested wildlife, fish and shellfish. Invasives are a threat to our built environments including landscaping, infrastructure, industry, gardens and pets. Invasives can affect recreational areas and human health.

The NYS Invasive Species Council was charged with developing a recommended four-tier system for invasive species management. The regulatory four-tier system required by statute assigns one of three regulatory categories to all species of non-native plants and animals, from the most restrictive category of “Prohibited Species” to “Regulated Species” to “Unregulated Species”. The number of persisting non-native species in New York is 1,405. The number of persisting non-native species assessed as having a High or Very High invasive nature in New York as of January 2010 is 68. Though not an exact figure, Dutchess County probably has at least 75% of all non-native species though only a few are high in density:

Top Ten invasive species with an assessment of “Very High” Invasive Nature based on DEC 4-Tier Assessment.


Common Name

Scientific Name


Eurasian Watermilfoil

Myriophyllum spicatum


Japanese Knotweed

Fallopia japonica


Autumn Olive

Elaeagnus umbellata


Broadleaf Water-Milfoil

Myriophyllum heterophyllum


Common Reed Grass

Phragmites australis


Water Thyme

Hydrilla verticillata


Mile-A-Minute (MaM)

Persicaria perfoliata


Purple Loosestrife (PL)

Lythrum salicaria


Japanese Barberry (JB)

Berberis thunbergii


Black Swallow-wort (BSW)

Cynanchum louiseae

There are some additional highly destructive invasive species that are either in Dutchess County or within striking range of Dutchess County that should be mentioned and monitored:

Significant Invasive Species either in, or within close proximity to Dutchess County, NY.


Common Name

Scientific Name


Brown Marmorated Stink Bug (BMSB)

Halyomorpha halys


Emerald Ash Borer (EAB)

Agrilus planipennis


Hemlock Woolly Adelgid (HWA)

Adelges tsugae


Japanese Stilt Grass (JSG)

Microstegium vimineum


Viburnum Leaf Beetle (VLB)

Pyrrhalta viburni

The table below provides a list of other invasive species common to Dutchess County that have increased in population over the past ten years:

Invasive Species Common to Dutchess County that have Increased in Population.

Garlic Mustard

Alliaria petiolata

Porcelain Berry

Ampelopsis brevipedunculata

Oriental Bittersweet

Celastrus orbiculatus


Artemisia vulgaris

Tree of Heaven

Ailanthus altissima

Chinese Water Chestnut

Eleocharis dulcis

Zebra Mussels

Dreissena polymorpha

Japanese Beetle

Popillia japonica

Multi-Colored Asian Lady Beetle

Harmonia axyridis

For More Information on Invasive Species

Contact the CCEDC Commerical Horticulture Program.