Volunteers are needed to pull Japanese stiltgrass (Microstegium vimineum) at Burlingame State Campground, in Charlestown, RI, Thursday, August 13th, 2009, at 10:00 a.m.

RI Department of Environmental Management Park Naturalist Neil Anthes will lead the charge against this big-time bad guy of the plant world.

Japanese stiltgrass (Microstegium vimineum), is an annual grass, native to Southeast Asia. The grass is believed to have arrived in the US in a packing crate of china delivered from Asia, and was first noted in Tennessee in 1919. Since then it has spread north and east.

Japanese stiltgrass can be most readily identified by the iridescent, silvery mid-vein on the upper leaf surface, and the “stilt-like” nature of the roots as they extend down from each leaf node.

In Rhode Island, the grass is considered an “early detection” species, of which there are five known locations throughout the state. The Burlingame site is largest of these, and includes locations within the adjacent Audubon Society of RI’s Kimball Refuge. It is found at camp sites and trail sides throughout the campground.

Japanese stiltgrass is of particular concern in forest environments, as it is well adapted to growing in low light conditions. The grass grows rapidly from July to September, forming dense mats, which cover existing native vegetation. Over the course of two seasons, dense stands of Japanese stiltgrass can out compete, and replace native herbaceous species. The grass is tolerant of moist conditions and so has the potential to spread throughout the wetland habitats surrounding the campground and along the Watchaug Pond shoreline. The seeds are buoyant and are easily carried through drainage ditches and streams. The seeds are also equipped with awns at the tip, which facilitate dispersal. The awns attach to bicycle tires, boots treads, animal fur etc. and then are carried further into the surrounding woodland habitat.

Because it is an annual, pulling before seed-set is an effective eradication technique. Removal of the grass by hand is easy, as it has short fibrous roots. August is the ideal time to pull the grass, as most of the seeds have germinated but most plants are only beginning to flower.

Please bring gloves and plenty of water, insect repellent and a lunch.

For more information and to sign up please contact either Neil Anthes via email at the following address: undefinedrecords@yahoo.com or Hope Leeson at the Rhode Island Natural History Survey (401) 874-5800, or hleeson@rinhs.org

RINHS received the following text from the Massachusetts Introduced Pests Outreach Project, a collaboration between the Massachusetts Department of Agricultural Resources and the UMass Extension Agriculture and Landscape Program, aimed at preventing the establishment of new pathogens and pests in Massachusetts. Visit their website for more information (http://www.massnrc.org/pests).

PATHOGEN ALERT: Late Blight of Potatoes and Potatoes

Late blight, a destructive disease caused by Phytophthora infestans, is a pathogen of tomato and potato plants that has recently been found in several states in the Northeast, including Maine, New York and Pennsylvania. The late blight has been identified on tomato transplants sold in big box stores and other garden centers under the brand name Bonnie Plants, and has also been found in a potato field in Pennsylvania. Because a few instances of late blight have now been detected on tomato plants in our state, the Massachusetts Department of Agricultural Resources (MDAR) is asking anyone growing tomatoes or potatoes to monitor them for signs of the disease, in order to prevent its further spread.

Late blight, the disease that was responsible for the Irish potato famine in the mid-19th century, is caused by a fungus-like pathogen that spreads through splashing rain or wind currents. Spores can disperse from one to several miles from the point of origin, with the infection spreading most efficiently in conditions of high moisture and temperatures ranging from 60° to 80°F.

Symptoms of late blight include small olive green or brown lesions on the upper surface of the foliage or the stems. Under moist conditions, there is a white, fuzzy growth on the underside of the leaves where the lesions occur, but the absence of this growth does not rule out late blight. Eventually the lesions turn black, leaves start to die, and then the entire plant dies.

This is a serious, destructive disease that can spread quite rapidly when conditions are right, infecting an entire field within days. Any gardeners who suspect they have tomato or potato plants infected with late blight should dig them up, place them in plastic bags, and dispose of them in the trash. Commercial growers wishing to control late blight should begin spraying fungicide immediately, even before symptoms are spotted. Spraying must continue regularly, using a product containing chlorothalonil, a state restricted fungicide which requires certification to use. Growers should be prepared to destroy the plants if the late blight starts to become severe.

For more information about late blight of potato and tomato, including diagnostic images, see the following websites:

Breaking Info from UMass Extension: http://www.umassvegetable.org/LateBlightAlertforTomatoandPotato.html
Fact sheet from Cornell University: http://vegetablemdonline.ppath.cornell.edu/factsheets/Potato_LateBlt.htm
Photos: http://www.hort.cornell.edu/department/Facilities/lihrec/vegpath/photos/lateblight_tomato.htm
Info about systemic fungicides: http://www.nevegetable.org/index.php/crops/tomato-outdoor?start=4

If you think you have seen late blight of potato and tomato in Rhode Island, contact the Rhode Island Department of Environmental Management, Division of Agriculture, 235 Promenade Street, Providence, RI 02908-5767, (401) 222-2781, http://www.dem.ri.gov/programs/bnatres/agricult/index.htm.

  

Have You Seen This Plant?

Two new observations of Mile-a-Minute Vine (Persicaria perfoliata, syn. Polygonum perfoliatum) were made in Rhode Island in September 2008, resulting in a total of three known locations, in three Rhode Island municipalities.

Mile-a-Minute Vine was first reported growing wild in Pennsylvania in the late 1930’s, and has spread north from there. Connecticut has eighteen known locations; most of which occur in the southwestern part of the state. Massachusetts has two locations. No sites are known for New Hampshire, Maine or Vermont. For this reason, land conservationists are pushing to eliminate Mile-a-Minute Vine in New England before it becomes pervasive. Experience from Connecticut has shown that while seeds are dispersed by natural means (birds, rodents and water), the primary mode of distribution is through humans moving soil or plant material that contain the seed.

Mile-a-Minute Vine is a highly invasive herbaceous vine that is native to Eastern Asia. The name, Mile-a-Minute Vine, comes from the plant’s ability to grow as much as 6 inches in one day; making Black Swallowwort seem like a slow-growing lichen. By the end of the growing season, plants form dense mats over existing vegetation. Although the species is an annual, vines persist through the winter giving new seedlings an ample armature on which to grow. Successive years of growth result in the death of underlying shrubs and herbaceous vegetation. The plant has been dubbed, “the Kudzu of the north”.

Mile-a-Minute Vine is tolerant of many growing conditions, with a preference for sunny, moist soils. The stem is covered with numerous downward pointing prickles, which give the plant its alternate common name, “Asian Tear-thumb.” The leaves are 1″ to 3” wide, forming a nearly perfect equilateral triangle. Prickles also occur along the mid-vein. A distinctive, saucer shaped leaf encircles the stem at each node. Seeds germinate in early to mid-May, with vines growing throughout the summer. Small white flowers appear in late August, and by September, the plant produces bright metallic blue berries which are fed on by birds and rodents. The fruits are buoyant, so preventing spread along water courses is of primary concern. The dense, barbed growth greatly impairs access to areas for people and wildlife, and some have nick-named Mile-a-Minute Vine “The Velcro Plant” because of the clinging nature of the stems.

Control of small populations is best achieved by hand pulling plants throughout the growing season, before fruit is set (generally mid-June to late September). Seeds remain viable in the soil for about seven years, so sites need annual attention to eradicate the plant. Herbicides, in the form of pre and post-emergent sprays, have also been effective, but must be used with a surfactant, and in accordance with the Label and state pesticide regulations.

Please help find and control this invasive plant. Click on the images above to enlarge the Mile-a-Minute Vine photos taken by Kim Gaffett on Block Island last fall. For more information, or to report a citing, call the Survey office at: (401)874-5800, send an email to: hleeson@rinhs.org, or go to the “RI Invasive Species Portal” at www.rinhs.org; and follow links to “contribute data”.

Several web sites can provide useful information on control and photographs of the plant to aid in identification: www.hort.uconn.edu/cipwg and www.nps.gov/plants/ALIEN/fact/pepe1.htm. 

Local botanists have gotten together to build a new website intended to support those interested in Rhode Island’s native plants, especially its wild flowers. The site is among-ri-wildflowers.org, and it is managed by Kathy Barton. The site’s name honors William Whitman Bailey, Brown botany professor and early Rhode Island Naturalist, who wrote a book on the state’s flowers by that name. The site currently includes notes on the 2008 field season and a really great summary of Rhode Island’s orchid species. We wish Kathy and her un-indicted co-conspirators luck with the site and hope botanists of all stripes will support it with information, photos, and other help. We look forward to watching it develop.

Some other recommended sites for those interested in Rhode Island plants:

Rhode Island Wild Plant Society

New England Wild Flower Society

Connecticut Botanical Society