Thursday, August 24, 2017

Alert: New Mile-A-Minute Infestation Found in Woodstock

Triangular leaves of Mile-A-Minute vine
Mile-A-Minute (Persicaria perfoliata) is a highly invasive, herbaceous annual vine native to eastern Asia.  It was unintentionally introduced in contaminated soil into the United States in Pennsylvania and Maryland in the 1930’s. It is an aggressive invader, earning its common name by its fast growth, up to six inches a day!  It grows as a vine, using its spines to climb over other plants, and it reproduces by seed. Mile-a-minute weed is a a prolific seeder and flowers for a long period of time, late summer through October, so can produce many fruit during one season.  Vines are killed by Fall frost and the seeds overwinter in the soil. Seeds can be viable in the soil for up to 6 years and germinate at a high rate.  
Mile-a-minute colonizes disturbed areas along forest edges, wetlands, stream banks and roadsides. It thrives in full sun and prefers high soil moisture.  Mile-a-minute outcompetes native species by its rapid growth and ability to grow over other plants and shade them out.  This plant often grows in streamside habitats and because the seeds can float, the seeds can be carried downstream, aiding the spread of this plant to previously uninfested areas.  Although the main vector for seed dispersal are birds that eat the fruits and deposit the seeds in their droppings, and other animals that ingest the seeds also contribute to the spread of this plant.
Ocrea encircling the stem
Mile-a-minute vines have alternate, light green triangular leaves, 4 to 7 cm long and 5 to 9 cm wide. The vines are light green and become reddish as they mature. The vine stems and the undersides of leaves are covered with recurved barbs that help it to hold onto objects and climb. A unique feature of mile-a-minute is that it has 1-2 cm diameter round, flat leaves, called “ocreae, “that circle the stems at the nodes. Ripe fruits are blue.

The newly discovered population of this plant in the Town of Woodstock is spread over an area of about ¾ acre.  Catskill Regional Invasive Species Partnership (CRISP) staff are working with the landowner to treat this population and are concerned that there may be other populations.  Mile-a-minute is widespread in the lower Hudson Valley, but this is only the second population that we know about in the CRISP region, with the other CRISP infestation along the Delaware River.  The closest known population to the Woodstock patch is 18 miles away in the Town of Esopus, outside of the CRISP region, in the Lower Hudson Partnership for Regional Invasive Species Management region.
Blue Fruit
If you think you see this plant in the CRISP region, please contact us at jthompson@catskillcenter.org or (845) 586-2611. 

Wednesday, March 15, 2017

Watch Out for Oak Wilt

Tree with oak wilt. Photo by NYS DEC staff.
In 2016 oak wilt was found at new locations in Islip, Riverhead, Southhold, Brooklyn and Canandaigua in addition to a known location in Glenville, New York. Since so many new locations surrounding our region were discovered last year, it is important that we are all aware of what the signs of this disease are and that any new locations are discovered quickly and reported.

Oak wilt (Ceratocysis fagacearum) is a fungus that infects the conductive tissue (water carrying cells) of oak trees.  The fungus blocks the flow of water and nutrients from the roots to the crown of the tree. Susceptibility depends on the species of oak.  Species in the red oak group may die within 1-5 weeks, while species in the white oak group may persist for years. In red oaks, fungal spores can be transported through all parts of the tree as the tree nears death; but in white oaks the distribution of spores only occur in the xylem of the current year’s growth.

Oak wilt was first discovered in Wisconsin in 1944 and has spread through the Midwest from Minnesota to Texas.  It was first found in New York State in 2008 at the Glenville site.  

Symptoms of oak wilt include browning of the leaves from the tip and edges moving in towards the midrib of the leaf.  Trees will shed leaves in late spring to early summer.  Infected red oaks lose their leaves from the top down, while in the white oak group leaves are lost in sections. 
Necrosis of the leaves from tips and margins. Photo by NYS DEC staff.
The fungus can spread naturally in two ways: above ground by beetles and below ground through root grafts. The fungus produces a fruity smelling mat of fungal spores under the bark of oak trees killed by the oak wilt fungus. These spore mats attract sap feeding beetles which can carry the spores from diseased trees to healthy trees. The sticky spores from these mats adhere to the insects’ bodies, and the beetles carry the spores to wounds on healthy trees. Oak wilt is also transmitted from tree to tree by underground connections called root grafts. Fine root grafts commonly occur between trees.
Humans can also spread the fungus over long distances by moving infected wood products or nursery stock.

If you observe an oak tree dropping leaves in early summer, and suspect that you are seeing symptoms of oak wilt, please take pictures of symptoms and report your sighting to DEC Forest Health or call 1-866-650-0652.  To learn more about oak wilt and Early Detection in our region, watch for upcoming CRISP events!