Tag Archives: Invasive Species

Invasive Species Spotlight – Mugwort

Name: Mugwort or Common Wormwood (Artemisia vulgaris)

Origin: Mugwort is native to Europe and Asia, where it was utilized as a medicinal and culinary herb. It was introduced to North America through ship ballast and continues to spread across the continent via nursery stock, turf grass and roadways.

NYS Presence: Widespread throughout the state and often found in ditches, roadsides, pastures and other disturbed areas.

Species Profile: Mugwort is a perennial that flowers in late summer to early fall. Its alternating dark green leaves are smooth on top and have silvery-white hairs underneath. When the foliage is crushed it is known to release a pungent odor. One plant can produce as much as 200,000 seeds which are roughly 1mm in diameter and are spread by the wind and easily moved around on tires, mowers and construction equipment. As a result, Mugwort can be found along miles of roadside.

Mugwort
Note the difference in color from the top (green) and the bottom (gray), image from https://extension.umass.edu/landscape/weeds/artemisia-vulgaris

Although seed dispersal plays a large role in the spread of this invasive weed, its root system is also a culprit in increase this weed’s introduction to new sites. Nursery stock including ornamental plants, turf grass, and orchard stock are easily contaminated by these root fragments and carried into new places. Mugwort’s rhizomatous roots – an extensive and dense underground network — and the abundance of seeds make this species very hard to control.

ArtemisiaVulgaris_Christian Fischer, accessed from Wikicommons
Mugwort in flower, photo by Christian Fischer, accessed from Wikicommons.org

Mugwort has displaced many native plants, especially those that thrive in sunny, open habitat. Cleaning equipment, using clean fill (e.g., at construction or landscaping sites), and removing and disposing of any new infestations of Mugwort are some of the ways to reduce the spread of this plant.

Resources:

Barney, J.N. and A. DiTommaso. 2003. The biology of Canadian weeds. 118. Artemisia vulgaris L. Canadian Journal of Plant Science 83:205-215.

https://www.forestandwatersolutions.com/uploads/3/6/3/1/3631108/japanese_knotweed_mugwort_pale_swallowort.pdf

http://www.nyis.info/index.php?action=invasive_detail&id=63

http://www.nrcresearchpress.com/doi/pdf/10.4141/P01-098

Featured image, mugwort growing along a forest edge, photo by Ansel Oommen, Bugwood.org

Invasive Species Spotlight – Giant Hogweed

Name: Giant Hogweed (Heracleum mantegazzianum)

Origin: This species is native to the Caucasus Mountains of Eurasia. It was brought first to Europe and the UK in the 19th century, followed by the US in the early 20th century to be used as an ornamental plant in flower gardens.

NYS Presence: Giant hogweed has become established throughout the entire state.

Species Profile: Giant hogweed can grow to extreme heights of 15 to 20 feet! Its robust stems are covered with dark purple colored blotches and elevated nodules. Some of these stems can reach 4 inches in diameter! Giant hogweed leaves are proportional in size, with some reaching a width of 5 feet. These leaves are compound, greatly incised, and lobed. Its flowers grow in a flat-topped formation that can be easily compared to an umbrella. This cluster of flowers can reach up to 2 ½ feet across. A few species that can be mistaken as giant hogweed are as follows: native cow parsnip, native purple-stemmed angelica, and invasive wild parsnip.

Terry English, USDA APHIS Bugwood.org
Giant hogweed in flower, notice how it resembles Queen Anne’s lace. These flowers may be up to 2-1/2 feet in diameter compared to the 3″-4″ flower diameters on Queen Anne’s lace, photo by Terry English, USDA APHIS accessed from Bugwood.org.

Giant hogweed is often found in wetland areas near rivers, where it is known to out compete other species for habitat. When native plants are displaced, bank erosion may also increase. This plant is labeled as invasive or noxious due to its poisonous sap. This sap contains a chemical that sensitizes the skin to UV rays. If the skin comes in contact with the sap and is exposed to sunlight, the results may be blistering, severe burns, and/or painful sores. Irritation usually appears within 1 to 3 days after the exposure. This reaction is called “phytophotodermatitis”. Follow this link to the giant hogweed hotline number and other tips for what to do if you or someone you know encounters giant hogweed.

Resources:

Giant Hogweed

NYS DEC Giant Hogweed – Don’t Touch that Plant

Invasive Species Spotlight – Kudzu

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Kudzu along the Old Croton Aqueduct State Historic Park in Yonkers, photo courtesy of Shawn Gorman, Friends of Old Croton Aqueduct

Name: Kudzu (Pueraria montana)

Origin: Kudzu was first introduced to the southern US in the late 1800’s as an ornamental plant to shade porches. In the early 1900s, farmers were encouraged to plant kudzu for erosion control and in the 1930’s the Civilian Conservation Corps (CCC) planted thousands of acres of it along hillsides for that same purpose. Kudzu wasn’t recognized as an invasive species by the USDA until 1953.

 NYS Presence: Lower Hudson Valley and Long Island

 Species Profile: Kudzu is a perennial, semi-woody, climbing vine that can reach up to 100 feet in length! Kudzu leaves are compound (i.e., made up of three separate leaflets) and are oval to heart-shaped. In the late summer, vertically growing stems produce fragrant purple flowers that are followed by the production of hairy, brown, flattened seed pods. Kudzu can grow up to one foot per day, which makes it capable of outgrowing almost anything! This fast-growing plant competes with native trees and plants for sunlight, water and nutrients from the soil.

Roughly 2 million acres of forests in the southern US are covered with kudzu! Let’s prevent this from happening in NY. If found, please report findings to iMapInvasives. Take note of your location, photograph the species and then upload!

Reminder: Poison ivy is another species with three leaflets, so be sure to brush up on your plant ID before handling these species.

Click here to learn more about kudzu.

Invasive Species Spotlight – Spotted Lantern Fly

What is the spotted lanternfly?

The spotted lanternfly (SLF) is an invasive pest from Asia that primarily feeds on tree of heaven (Ailanthus altissima) but can also feed on a wide variety of plants such as grapevine, hops, maple, walnut, fruit trees and others. This insect could impact New York’s forests as well as the state’s agricultural and tourism industries.

Identification

Nymphs are black with white spots and turn red before transitioning into adults. They can be seen as early as April. Adults begin to appear in July and are approximately 1 inch long and ½ inch wide at rest, with eyecatching wings. Their forewings are grayish with black spots. The lower portions of their hindwings are red with black spots, and the upper portions are dark with a white stripe. In the fall, adults lay 1-inch-long egg masses on nearly anything from tree trunks and rocks to vehicles and firewood. They are smooth and brownish-gray with a shiny, waxy coating when first laid.

Where are they located?

SLF were first discovered in Pennsylvania in 2014 and have since been found in New Jersey, Delaware and Virginia. As of spring 2018, New York has no infestations, though it’s possible they are present in low numbers and have not been detected yet. Given the proximity of the Pennsylvania infestation, it is expected to be found in New York eventually.

Hatched eggs
Hatched spotted lantern fly eggs, photo by Kenneth R. Law, Bugwood.org

What is the risk to NYS?

SLF pose a significant threat to New York’s agricultural and forest health. Adults and nymphs use their sucking mouthparts to feed on the sap of more than 70 plant species. Feeding by sometimes-thousands of SLF stresses plants, making them vulnerable to disease and attacks from other insects. SLF also excrete large amounts of sticky “honeydew,” which attracts sooty molds that interfere with plant photosynthesis, negatively affecting the growth and fruit yield of plants. New York’s annual yield of apples and grapes, with a combined value of $358.4 million, could be impacted if SLF enters New York. The full extent of economic damage this insect could cause is unknown at this time. Although native insects also secrete honeydew, the size of SLF and the large populations that congregate in an area result in large accumulations of it. The sticky mess and the swarms of insects it attracts can significantly hinder outdoor activities. In Pennsylvania, where SLF populations are the densest, people can’t be outside without getting honeydew on their hair, clothes, and other belongings.

Adults
A cluster of adult spotted lantern flies, photo by Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org

How do they spread to new areas?

While SLF can jump and fly short distances, they spread primarily through human activity. They often hitch rides to new areas when they lay their eggs on vehicles, firewood, outdoor furniture, stones, etc. and are inadvertently transported long distances.

Fungal Mat at base of tree
Fungal mat at the base of a tree that is infested with spotted lantern flies, photo by Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org

What are the signs of an infestation?

  • Sap oozing or weeping from tiny open wounds on tree trunks, which appears wet and may give off fermented odors.
  • One-inch-long egg masses that are brownish-gray, waxy and mudlike when new. Old egg masses are brown and scaly.
  • Massive honeydew build-up under plants, sometimes with black sooty mold.

What is being done?

NY Dept. of Conservation, DEC, is working with the NYS Department of Agriculture and Markets and the US Department of Agriculture to address SLF. Since it is less expensive and easier to deal with a pest before it becomes widespread, the goal is to find SLF early or prevent it from entering NY altogether. A plan has been developed that describes how the agencies will prevent and detect SLF in New York. Extensive trapping surveys will be conducted in high risk areas throughout the state as well as inspections of nursery stock, stone shipments, commercial transports, etc. from Pennsylvania and New Jersey. DEC and partner organizations encourage everyone to be on the lookout for this pest. State Parks and others are also mapping locations of tree of heaven, an invasive tree that is a known host of SLF to target places to look for SLF. Where feasible, reducing populations of tree of heaven may also be beneficial.

What can I do?

  • Learn how to identify SLF.
  • Inspect outdoor items such as firewood, vehicles, and furniture for egg masses.
  • If you visit states with SLF, be sure to check all equipment and gear before leaving. Scrape off any egg masses. Visit agriculture.pa.gov for more information on SLF in PA.
  • Learn about invasive species during New York Invasive Species Awareness Week.

If you believe you have found SLF in New York…

  • Take pictures of the insect, egg masses and/or infestation signs as described above (include something for scale such as a coin or ruler)
  • Note the location (address, intersecting roads, landmarks or GPS coordinates)
  • Email the information to DEC at spottedlanternfly@dec.ny.gov
  • Report the infestation to iMapInvasives

 

Printer friendly version of this information can be found here.

Invasive Species Spotlight – Hydrilla

Hydrilla is one of the highest priority invasive plants in New York State.  It outcompetes native plants and causes destruction in our aquatic habitats. It can invade the deeper waters where many of our natives cannot and can aggressively grow up to an inch per day. This allows hydrilla to form thick mats at the top of the surface blocking sunlight for the native plants below.  Oxygen is then depleted leading to a decrease in the amount of oxygen in the water and potential fish kills. Sportfish weight and size can decrease due to the loss of open water and natural vegetation and their spawning habitats can be eliminated by hydrilla. The species also causes obstructions for boating, swimming, and fishing. The large dense mats of vegetation can cause property value to decrease, creating problems for homeowners and communities. Hydrilla not only affects our native habitat but also our local communities and businesses.

Hydrilla is a perennial plant. It grows in springs, marshes, lakes, canals, and rivers. This plant can tolerate low and high nutrient conditions and up to 7% salinity. There are two kinds of hydrilla; a southern population which is comprised of mostly dioecious females (meaning the plants only have female flowers), and northern populations which are monoecious (meaning the plants have both male and female flowers).  The dioecious females overwinter as perennials. The monoecious plants set fertile seed and depend on their tubers for overwintering. Hydrilla can reproduce four different ways, including fragmentation, tubers, turions, and seeds. Fragmented pieces with one node are able to sprout into a whole new plant. Tubers are formed on the rhizome of the plant and each one can produce up to 6,000 new tubers! These tubers can lay dormant for over four years before sprouting into a new plant. Turions, or dormant buds, form in the leaf axil of the plant and then break off and settle into the sediment to produce a new plant. Seed dispersal is the least important reproductive method for the species and is often facilitated by ingestion and subsequent dropping of migratory birds. These plants can grow in low light conditions, deep depths and can photosynthesize earlier in the morning than their native competitors. At its beginning stages it can grow up to an inch a day until it reaches the surface of the water.

Leaves_Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Note how small the hydrilla leaves are, photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Identifying hydrilla can be very tricky at times because it looks similar to a native plant, American elodea, and another invasive plant, Brazilian elodea. There are a few distinguishing characteristics that set hydrilla apart from the other two aforementioned species. The leaves are 5/8 inches long and they grow in whorls of 3-10, 5 leaves per whorl being most common. The leaves have distinct serrated edges. A key feature is the dull-white to yellowish, potato like tuber that grow 2-12 inches below the sediment.

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
A dense mat of hydrilla, photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Hydrilla is thought to have originated from the island of Sri Lanka and possibly the southern mainland of India, but it arrived in the United States from Korea as a popular aquarium plant. Colonies were first identified in canals in Miami and Tampa, Florida. Hydrilla fragments made their way up to New York by attaching to boats, their trailers, and live wells. Boat motors, oars, and other equipment break the plant into fragments, facilitating its spread throughout the affected water body and into nearby water bodies that are hydrologically connected. Hydrilla can spread between water bodies that are separated by geographic distance by “hitching a ride” on watercraft trailers and other recreational equipment. The first time hydrilla was discovered in New York was in August 2011, when Jordan Stark found the species in Cayuga Inlet in the Finger Lakes In September of 2012, the species was found in the Erie Canal in North Tonawanda by a U.S. Fish and Wildlife biologist. It has also since been found in Long Island, including Caleb Smith State Park Preserve in Phillips Mill Pond. Since the introduction of hydrilla in New York, a coalition of partners, which includes many state agencies, non-profit organizations, and businesses have taken quick action to help prevent its further spread. After a population of hydrilla is found, partners mobilize resources to conduct a focused education and outreach campaign and survey the area where hydrilla was found to understand the full extent of the population. Once surveying is completed a management plan is implemented, which includes aquatic herbicide application. To learn more about best management practices, please go to http://hydrillacollaborative.com.

Want to help manage this unruly aquatic plant? Learn how to properly identify hydrilla. If you think you found hydrilla take pictures, mark your location, and contact your regional DEC office or submit your observation with pictures on the iMapInvasives mobile app or website. Also, it is important to clean, drain, and dry your boats and any fishing or recreational equipment!

Hydrilla treatment Erie Canal
Treating hydrilla on the Erie Canal.

References

“Cornell Cooperative Extension Tompkins County.” 2011 Hydrilla Eradication Efforts. N.p., n.d. Web. 11 Sept. 2014. http://ccetompkins.org/environment/invasive-species/fighting-hydrilla2011

“Hydrilla (Hydrilla Verticillata (L.f.) Royle).” New York Invasive Species Information. N.p., 3 Oct. 2012. Web. 11 Sept. 2014. http://www.nyis.info/?action=invasive_detail&id=16

“Aquatic Invasive Species.” HYDRILLA (n.d.): n. pag. Web. 11 Sept.2014 www.in.gov/dnr/files/hydrilla.pdf

“Highly Invasive Aquatic Plant Threatens New York’s Waters.” Department of Environmental Concervation. N.p., 21 Sept. 2012. Web. 11 Sept. 2014. http://www.dec.ny.gov/press/85078.html

“Combating Hydrilla.” US Army Corps of Engineers. N.p., 14 Aug. 2014. Web. 11 Sept. 2014. http://www.lrb.usace.army.mil/Media/NewsStories/tabid/6146/Article/494240/combating-hydrilla.aspx