Here’s some hot news from our neighbor to the north (and east). The Massachusetts Introduced Pest Outreach Project reports that “Chrysanthemum white rust (Puccinia horiana, “CWR”), a serious fungal disease of chrysanthemums, has been discovered in Massachusetts. Infected plants were discovered at nurseries and at retail locations, with diagnoses confirmed by plant pathologists from USDA APHIS-PPQ. This pathogen can spread quickly in greenhouse and nursery environments, causing severe crop losses.

Over the last 25 years, localized introductions of chrysanthemum white rust have occurred within the United States or Canada and have subsequently been eradicated. Earlier this month, CWR was reported to have overwintered in an outdoor planting of mums at a residential property in Connecticut, and was also found at nurseries in Pennsylvania and Michigan. CWR is a pest of quarantine significance in the United States, requiring state and federal regulatory action. The MA Department of Agricultural Resources and USDA APHIS-PPQ are currently working together with nurseries to eradicate it from Massachusetts.

Chrysanthemum white rust attacks several species of chrysanthemums, including potted mums, spray mums, and garden mums. The symptoms of this disease are very distinct. Light green to yellow spots up to 5mm in diameter appear on the upper surface of the leaf. The spots become brown and necrotic with age. Raised beige to pink pustules form on the underside of leaves. These pustules become white with age. Pustules are most common on young leaves and flower bracts but may form on any green tissue or the petals. Symptoms are more likely to be observed during or following cool, wet weather.

For more information about chrysanthemum white rust, including lists of susceptible and resistant species and a detailed eradication protocol, see our fact sheet at http://massnrc.org/pests/pestFAQsheets/chrysanthemumwhiterust.html. If you think you have seen Chrysanthemum White Rust, please call the MDAR Plant Pest Hotline at 617-626-1779, or report it on this website: http://massnrc.org/pests/.”

The Mass. Introduced Pest Outreach Project is a nifty little program and you can learn more about it or sign up to receive you own email copy of their announcements by visiting their web site: http://www.massnrc.org/pests/

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The Rhode Island Natural History Survey, URI Cooperative Extension’s Watershed Watch Program, and the Rhode Island Department of Environmental Management are sponsoring an evening educational program entitled, “What’s in the pond? A look at freshwater invasive plants and their management.” The presentation will be held on Tuesday, October 7 from 6-8:30 pm, in the Weaver Auditorium located in the Coastal Institute Building on URI’s main campus in Kingston. The event is open to the public (including our neighbors in Connecticut and Massachusetts), however advance registration is required as seating is limited. The cost to attend is $5.00, payable at the door. Light refreshments will be provided. Please register by Monday October, 6^th through the URI Watershed Watch office at 401-874-2905 or 401-874-4552, or via email.

Although aquatic plants are a beneficial component of freshwater pond ecology, the proliferation of non-native species can have a negative impact on the health and function of a waterbody. Generally referred to as “exotic, invasive, or weeds”, non-native plants can crowd out native aquatic plants, reducing biodiversity, a healthy mix of plants and animals, as well as harm water quality. The evening presentation will focus on the ecology of aquatic plants, the invasive species presently known to be in Rhode Island waters, as well as some that are in our neighboring states. Management techniques will be presented as well as a discussion of Rhode Island’s new Aquatic Herbicide application process.

As a part of the event, the Rhode Island Natural Survey will accept freshwater aquatic plants for identification. A maximum of 5 plants will be accepted per participant. Those bringing in plants for identification will be asked to fill out a form detailing where the plant was collected (Aquatic Plant ID Submission Tag PDF 91K). Plants submitted for identification should be presented as follows: Collect one specimen of the plant, ensuring that the specimen contains all representative leaf types. Many aquatic species have a combination of underwater (submerged) leaves and above water (emergent) leaves and/or flowering structures. It is also important to collect representative flower or seed structures if possible, as they are often crucial for correctly identifying a plant. Flowers may be inconspicuous as they are often very small and may be somewhat hidden by being located where a leaf attaches to the stem.

Gently rinse all debris and dirt from the plant and its root structure. Place the cleaned specimen in a sealed plastic bag with enough tap water to keep the plant moist. Keep the bagged plant refrigerated until you deliver it to the RINHS staff on the night of October 7^th.

This program is part of RINHS’s Skills Workshop series. The ongoing series of evening programs is designed to provide training for naturalists and would-be naturalists in practical skills such as specimen preparation and identification and use of specialized equipment and literature. In 2008-09, the series is sponsored by the U.S. Fish & Wildlife Service.

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Well, as someone (there’s a debate about whom, but see this wikipedia page) once said, “No plan long survives the first encounter with the enemy.” Here’s how our first day went fighting mile-a-minute vine on Block Island.

Hope Leeson and I arrived on the ferry at 10 am. Thank you Scott Comings and The Nature Conservancy for providing ferry passage. We were met by TNC staff and taken to the site. We quickly located the patch, in the Fresh Swamp Preserve about 30 meters east of Lakeside Drive. We discovered the patch to be much larger and more advanced than I (at least) had been expecting. It extended north from the Preserve path 10-15 meters to a dirt road/driveway (that connects Lakeside Drive with Payne Road) and about 40 meters east to west. The coordinates of the center of the patch are N 41*09.706′ x W 071*34.577′.

Coverage for much of the area was approximately 90%. There were isolated plants and patches on the north side of the driveway as well, the most westerly being almost to Lakeside Drive and the most easterly being opposite the main patch, but on the other side of the road. There were two isolated, somewhat smaller patches on the path about 150 meters east of the main patch (Patch 1)–we called these Patch 2 and Patch 3. They were roughly 8 to 10 meters diameter each, with some stragglers more outlying.

We were joined by four volunteers, including naturalist, RINHS member, and New Shoreham First Warden Kim Gaffett. We took samples of the mile-a-minute vine as directed by Judith Hough-Goldstein. We collected 250 berries, including 150 from the first patch and 50 each from the patches east down the path. We also collected 8 samples of five leaves each from patch 1 and one sample of 5 leaves from each of patches 2 and 3. We also took video and still pictures of the extent of the patch, the pulling process, and other features we thought noteworthy. Hope looked for plants of interest in the understory but found nothing unusual. The scaffold plants consist of about 60% blackberry, 10% elderberry, and about equal proportions of bayberry, multiflora rose, bittersweet, and goldenrod making up the balance.

The mile-a-minute vine had completely covered all other plants except the odd blackberry cane that managed to stick out the top, including climbing over a 15′ high bayberry tree. In some places it was clear the vines were rooted around the perimeter of a shrub patch and had scambled up and over, but in others it was clear they were coming up densely from directly under their scaffold plants. In many places the rooted stems were at least 20 per square meter. Some individual vines were 20 feet long.

The pulling was relatively easy given the circumstances. In many cases it was possible to gather a bunch of stems low down at the edge of a bush and by twisting and pulling, create a hauser of vines that was strong enough to pull down a whole mat from off of a bush. These could be rolled up into a bundle for easy handling and to help prevent berries from dropping off. The thorns of the mile-a-minute vine were wicked if you had exposed skin but, as they are thin, short, and curved, almost any layer of cloth protected you well against them. The hardest part of pulling was dealing with thorns of the blackberry and multiflora rose. They made it hard to get into the bushes and easily pierced gloves, jackets, and even boots. The height of the MaM in the trees as also difficult to deal with. If a vine broke while you were pulling it, which was most of the time, you often couldn’t reach the (heavily fruited) rest of it up in the trees. I think we could have used a long-handled, metal garden rake to reach up and pull it down.

About the berries: the vines had numerous clusters of ripe berries and three or four times as many immature clusters. The berries come off very easily and the pulling released showers of berries onto the ground. Because of the easy with which these berries come off and bounce and roll around, I would recommend against trying to dispose of this material off-site. We initially bagged 9 bags of vines in plastic trash bags but soon abandoned that when it was clear the bags were full of rips from the thorns and there was a great risk of leaving a trail of seeds. After that we piled the vines into a great heap on top of an area already sprouting many many stems. This should keep the birds from getting most of the berries and as this ground will already have to be controlled next year, adding a few more shouldn’t matter. The pile we ended up with is 4 feet high, 4 feet wide, and 6 feet long and so solidly packed you could climb onto it.

Three of us worked until about 2:30 and Hope and I caught the 3 pm boat thanks to Kim and her car. The total person hours on site were 20. We pulled all the vines we could reach between the path and the dirt road, including all the vines at the two isolated patches down the path to the east. We left clumps of vines and berries that we couldn’t reach in the tops of a bush and a tree. There is a huge pile of vines about 10 feet south of the dirt road and there are nine bags stacked at the turnstile, but I’m having misgivings about moving the bags even that far as I’m afraid they’ll be dropping berries everywhere. If they haven’t been moved yet, I think they should left at the main infestation in a pile to solarize and compost on-site.

Given the size and density of the outbreak and the number of ripe seeds released by the pull, we can expect this area to be heavily infested with mile-a-minute next year. Given the absence of significant plants in the understory, I think TNC should consider using a brush-hog on the entire area between the path and the road and keeping it mown for several years until the seed stock of MaM is exhausted. TNC will also have to negotiate access to the land on the other side of the dirt road because there are significant patches there already and by next year there will be much larger ones.

Speaking of close by, when I got back into the office I found an email from Kim Gaffett. Apparently when she returned home yesterday she had a message from someone who’d been talking to one of the pullers. She said something like, “oh, I’ve got that growing at my house!” She lives on Lakeside Drive south of Fresh Pond, about a quarter mile from the other infestation. Kim sent me pictures of this new patch, which looks fairly large. The home owner pulled it all up that afternoon. So at this point, it is clear that MaM has been on Block Island for some years and has spread at least a bit in the Fresh Pond/south-center of the island area. After TNC has had some time to assess the spread of this plant on the island and the availability of resources required if a manual control effort is to be effective, they might want to talk to Judy Hough-Goldstein and Dick Casagrande about the possibility of a biocontrol. Judy is working on a weevil that has already been undergoing field tests in Pennsylvania. For information on this, see her website. Of course biocontrol with a beetle needs to be approached with caution as Block Island is the only R.I. site for important coleopterous rare species such as the federally listed Nicrophorus americanus.

Kim and I and others will keep working into the fall to try to spread word of this plant on Block Island and get a better idea of just how widespread it really is.

That’s the report.
David Gregg

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Mile-a-Minute Vine (Persicaria perfoliata, a.k.a. Polygonum perfoliatum) has been detected in Rhode Island, on The Nature Conservancy’s Fresh Swamp Preserve, on Block Island. The initial observation was made by Paulinka de Rochemont, a butterfly watcher who asked RINHS for help identifying an unfamiliar plant she’d seen on a recent outing. The identification was confirmed by Les Mehrhoff of IPANE and Bill Brumbach of NEWFS and the scope of the infestation was confirmed by Block Island naturalist and RINHS member Kim Gaffett. Here are Kim’s photos of the infestation, which is fairly significant in size. Nice catch, Paulinka!

RINHS is working with The Nature Conservancy’s Block Island Program and the Block Island Community to organize pulling day to collect the vines and keep the ripening berries from being picked up by birds this fall. The event will be on Wednesday, September 24. Details are still being planned, but anyone interested in participating should call RINHS at 401-874-5800. Those coming from the mainland will have to be responsible for their own ferry ticket, but hey, a day in a wildlife preserve on Block Island is worth a lot.

Mile-a-Minute Vine is native to Eastern Asia, including China, Korea, Japan, Taiwan, the Phillipines, and the Malay Peninsula. It is a member of the Buckwheat family (Polygonaceae). It was introduced accidentally into North America in the late 1930’s in Pennsylvania and has spread from there. It is an herbaceous, trailing plant, tolerant of many growing conditions but with a preference for moist soils and sunny situations. It is an annual in the Northeastern United States. It produces bright blue berries attractive to birds, which are the most likely vector in its spread. The fruit floats, so the plant may spread through water courses. The stem of Mile-a-Minute Vine is covered with numerous recurved barbs, from which it gets it’s alternative common name, “Asian Tearthumb.” The barbs assist it to scramble over other vegetation, which it then frequently smothers in dense growth. The dense, barbed growth greatly impairs access to areas for people and wildlife. Control is best acheived by pulling the plants before fruit is set (generally by mid to late summer). Herbicides are effective in killing the plant, but are likely to kill non-target plants that Mile-a-Minute climbs over, resulting in an opening in the vegetation that will promote the growth of surviving vines or new seedlings. For more information see: www.nps.gov/plants/ALIEN/fact/pepe1.htm

RINHS is a non-profit founded in 1994 to support those interested in studying and preserving the natural history of Rhode Island. A membership organization with over 400 members, RINHS facilitates the interests of naturalists through education and outreach programs, publications, web tools, and conferences, and by providing biodiversity data managment and technical assistance in field ecology and administrative capacity to land trusts, municipalities, government agencies, and researchers. Membership is open to all; for more information visit www.rinhs.org, email info[at]rinhs.org, or call 401-874-5800.

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