archive-org.com » ORG » M » MDINVASIVESP.ORG

Total: 261

Choose link from "Titles, links and description words view":

Or switch to "Titles and links view".
  • Invader of the Month_August 2004
    trees many other hosts suffer symptoms such as tip dieback and leaf spots The disease is increasingly being referred to as ramorum blight or ramorum dieback These foliar hosts may not die from the disease but can serve to move the pathogen around P ramorum can spread via infected plant tissue soil and water P ramorum is a relative newcomer As early as 1993 oaks and tanoaks in California and rhododendrons in Europe were dying mysteriously It wasn t until 2000 that the pathogen responsible for both was identified as P ramorum Since the mid 1990 s researchers regulators and stakeholders in Europe and North America have been working at a feverish pace to understand and contain the disease Until 2003 P ramorum was believed to be confined to native plants in the environment in northern coastal California Oregon and British Columbia in North America In 2002 USDA imposed a quarantine that now includes 13 counties in California and an area in Oregon to prevent its artificial spread through commerce In 2003 plants in Oregon and Washington nurseries tested positive for the pathogen Although the introduction was contained and eradicated concerns about the role of nursery plants in spreading the disease mounted In March of 2004 the California Department of Food and Agriculture reported that Monrovia Nursery in southern California far from the quarantine area had plants that tested positive for P ramorum In April 2004 the USDA imposed an Executive Order restricting any California nursery from shipping plants outside the regulated area without being first declared to be free of P ramorum Lists of trace forward nurseries those known to have received potentially infected material from California were sent to the affected states Of over 500 camellias viburnums and lilacs known to have been shipped to 11 nurseries in

    Original URL path: http://mdinvasivesp.org/archived_invaders/archived_invaders_2004_08.html (2016-04-30)
    Open archived version from archive


  • Invader of the Month_July 2004
    edge areas of the urban landscape The vine climbs by tendrils and can completely cover other plants As it climbs it attacks the shrub sapling and sub canopy levels of forest edges It forms dense green mats as it out competes our native species for light water and nutrients Summer is high season for Porcelainberry in the Mid Atlantic states so the Maryland Invasive Species Council MISC has chosen it as July s Invader of the Month The leaves of Porcelainberry are bright green coarsely toothed and slightly hairy on the underside They vary from a simple heart shaped grape leaf form to a slightly three to five lobed shape to a deeply dissected lobed form The leaves are arranged alternately on the stem and often leaves with very different lobe patterns appear on the same stem at the same time The colorful fruits are a distinguishing characteristic They are hard ¼ inch berries with a porcelain like sheen colored green pale lilac yellow white and blue in the same cluster at the same time Porcelainberry is native to eastern Asia including China Korea Japan and eastern Russia It was introduced as bedding shading and landscape planting material in the 1870s and is still widely used and promoted in some areas Birds and small mammals spread the seeds which germinate readily in the soil after natural or human disturbance Porcelainberry grows well in most soils and once established is difficult to remove without disturbing the roots of more desirable plants Like other aggressive vines Porcelainberry can cover trees shutting out light and causing them to weaken and collapse under the weight Native grape vines are sometimes mistaken for Porcelainberry and cut down Correct identification is crucial because native grapes produce important wildlife food and cover and since they evolved with

    Original URL path: http://mdinvasivesp.org/archived_invaders/archived_invaders_2004_07.html (2016-04-30)
    Open archived version from archive

  • Invader of the Month_June 2004
    areas create breeding grounds for mosquitoes and compared to native aquatic grass beds provide poor habitat to native fish and birds The water chestnut first appeared in Maryland in the Potomac River near Washington D C as a two acre patch in 1923 The plant spread rapidly covering 40 river miles within a few years By 1933 10 000 acres of dense beds extended downstream from Washington D C The proliferation of water chestnut resulted in the loss of native aquatic grasses and the U S Army Corps of Engineers responded by conducting a massive and well funded removal effort from 1939 to 1945 even as war raged in Europe The water chestnut was recorded in the Bird River in Baltimore County for the first time in 1955 The Maryland Departments of Game and Inland Fish and Tidewater Fisheries used mechanical removal and an herbicide to control that population However in 1964 it reappeared in the Bird River and an additional 100 acres were discovered in the Sassafras River in Kent County of which 30 acres were mechanically removed A combination of removal techniques was used once again in 1965 to remove 200 acres from the Sassafras This effort was believed to have been successful and no plants had been noted in vegetation surveys until the summer of 1997 The Bird River water chestnut population spread from approximately 50 plants in 1997 to over three acres in 1998 and approximately 30 acres in 1999 The Sassafras population was slightly larger but determining its exact size has been difficult due to its remote location A massive volunteer harvesting effort began on both rivers in 1999 and resulted in the removal of approximately 400 000 pounds of plants from the two rivers As impressive as the 1999 effort was the fact that

    Original URL path: http://mdinvasivesp.org/archived_invaders/archived_invaders_2004_06.html (2016-04-30)
    Open archived version from archive

  • Invader of the Month_May 2004
    that way The Maryland Invasive Species Council has chosen Sharka also known as plum pox as its May Invader of the Month because of the risk it poses to the Maryland s orchard industry should it cross the state border from Pennsylvania which has identified the disease in its stock To protect its industry Maryland has conducted surveys of its commercial orchards and nurseries since 2000 Currently surveys are underway in the northern counties of Maryland to test for the plum pox in backyard situations that are within one mile of commercial orchards Selected commercial orchards and nurseries in these counties will also be surveyed to support the national survey program Sharka also known as plum pox is considered the most serious disease affecting stone fruit like peaches apricots nectarines plums and almonds It is transmitted by several different aphid species and by humans through grafting with infected budwood and transporting infected nursery stock but has no harmful affect on humans Because of Sharka s detrimental affect on the production of stone fruits various countries have imposed tight quarantine restrictions to prevent the spread of infected nursery stock and budwood Plum pox virus causes different symptoms in different fruit trees In peaches infection ranges from almost no symptoms to yellowing bands and ring patterns on young leaves twisting and distortion of leaves and ring patterns on fruit Some peaches show breaks in coloration on flower petals Apricots become lumpy and small with bitter flavor Garden plums develop strong yellowy mosaic patterns on the leaves sunken ring patterns called pox in the fruit and drop their fruit prematurely In 1992 plumpox jumped to the Western Hemisphere showing up in Chile In 1999 it appeared in the U S in southern Pennsylvania followed by Canada in 2000 All infected orchards and homeowner

    Original URL path: http://mdinvasivesp.org/archived_invaders/archived_invaders_2004_05.html (2016-04-30)
    Open archived version from archive

  • Invader of the Month_April 2004
    Archived Invaders In the News Invasive Species of Concern in Maryland Information and Resources The Zebra Mussel IOTM has been updated and re issued Please visit the January 2015 Invader of the Month Click here to view the archived April

    Original URL path: http://mdinvasivesp.org/archived_invaders/archived_invaders_2004_04.html (2016-04-30)
    Open archived version from archive

  • Invader of the Month_March 2004
    Invaders In the News Invasive Species of Concern in Maryland Information and Resources The Emerald Ash Borer IOTM has been updated and re issued Please visit the January 2007 Invader of the Month Click here to view the archived March

    Original URL path: http://mdinvasivesp.org/archived_invaders/archived_invaders_2004_03.html (2016-04-30)
    Open archived version from archive

  • Invader of the Month_February 2004
    plant is thus easily moved into areas where it was never intended to be planted English ivy is also spread in improperly disposed of garden debris it roots very easily from pruned pieces discarded at the side of the road Introduced into this country by colonists from Eurasia English ivy today is widely sold as an ornamental plant It inhabits not only gardens but hedgerows woodlands coastal areas salt marsh and field edges It is extremely competitive even in shady areas although it does not do well in very wet conditions Once the ivy escapes gardens and grows into parklands and natural areas it causes several types of damage 1 It decreases biodiversity because it creates such a dense ground cover that it out competes native woodland plants which are often also under attack by white tailed deer 2 It damages trees both through the glue like substance that helps its holdfasts attach to bark and through limb fall caused by the weight of the vines Sometimes this extra weight can bring whole trees down especially in ice storms Control Techniques Control of English Ivy not only involves removal but also follow up monitoring and may require recolonization by planting native shrubs small trees and wildflowers especially in natural areas In most situations wholesale non selective methods such as spraying with an herbicide should be avoided Non selective methods often result in the removal of desirable woodland species that may persist in the understory like viburnums blueberries or ferns If possible remove English ivy by hand The first step is to cut near ground level all the vines that are climbing trees This will prevent further fruiting and seed dispersal and will unburden the trees It is not necessary to pull the vines from the trees in fact this may often do more harm than good The next step is to cut the ivy roots and to roll the mass of ivy vegetation as the roots are cut much like rolling up a giant carpet This is hard dirty work and it helps to have two or more people engaged in the process but it is not as enormous a task as it may seem Step three of the process is to help native plants recolonize the woodland understory This is crucial because nature abhors a vacuum and removal of the ivy disturbs the soil creating an opportunity for colonization by other aggressive potentially more troublesome invasive plants such as Japanese stilt grass Garlic mustard Multiflora rose or Japanese honeysuckle The likelihood of simply swapping one invasive plant species for another means that natural area managers including homeowners with woods on their properties must be especially careful when attempting remediation of woodlands infested with English ivy Often small bare root native woody plants are available for a relatively low cost per plant Seed mixes of native woodland wildflowers are also available and can be broadcast throughout the area where ivy has been removed No English ivy removal project is complete

    Original URL path: http://mdinvasivesp.org/archived_invaders/archived_invaders_2004_02.html (2016-04-30)
    Open archived version from archive

  • Invader of the Month_December 2003
    native to eastern Asia including Korea China and Japan It was introduced to the United States as early as 1736 as an ornamental plant It is a woody vine with rounded leaves that produces inconspicuous clusters of small yellowish flowers in spring Flowers and fruits occur where the leaves meet the stems Birds and small mammals eat and disperse the fruits Oriental bittersweet can cover tall trees causing them to weaken and collapse under the weight of the vines The stems twine around the trunks and as they thicken they can cut into the bark and girdle the tree Any small plants at ground level are cut off from light by the vines growing over them but oriental bittersweet seeds germinate best in shade A more subtle influence of the Oriental bittersweet invasion is its potential effect on the American bittersweet Celastrus scandens The very similar looking American bittersweet produces flowers and fruits only at the tips of the stems rather than along the stems American bittersweet is not aggressive and may be displaced by Oriental bittersweet The Oriental bittersweet may also hybridize with American bittersweet introducing its genes into the native populations and making it even more difficult to

    Original URL path: http://mdinvasivesp.org/archived_invaders/archived_invaders_2003_12.html (2016-04-30)
    Open archived version from archive



  •