Tag Archives: Help Stop The Spread

Monitoring for Southern Pine Beetle

Earlier this year, the Invasive Species Management Team kicked off the spring with the installation of several southern pine beetle (SPB) traps at Minnewaska State Park Preserve and a few other locations. Southern pine beetle, Dendroctonus frontalis, is a 2-4mm long bark beetle, reddish brown to black in color, that hails from the southeastern United States and attacks pine trees. The female will locate a host tree, most commonly one with a compromised defense system as noted by the presence of alpha-pinene, a chemical released by stressed trees. The females then release the pheromone frontalin to attract males for mating, as well as other males and females. Males also secrete a pheromone, endo-brevicomin, summoning more beetles to congregate. The beetles enter the trees through cracks in the bark. In an effort to eject the beetle, pine trees will produce resin to push them out. The resulting little, lumpy sap nuggets are called pitch tubes and are a good indicator of SPB infestation. Once in the tree, SPB starts constructing curved tubes, or galleries, in the cambium to lay their eggs in. It is in the cambium that we find the xylem and phloem tissue, which transports water and nutrients through the tree and therefore helping the tree growth. Larvae move to the inner bark immediately after hatching, and then to the outer bark to feed as they mature. When they become adults, they chew round exit holes in a “shotgun” pattern, large enough only to fit a pencil tip. The exit holes are another sign of infestation to be on the lookout for. The chewing of galleries disrupts the flow of water and nutrients, resulting in the needles fading and ultimately tree death in as little as 2-4 months. The Long Island Central Pine Barrens have been particularly damaged by SPB. This may be due in part to the lack of fire as a management technique to thin stands, reducing competition and therefore resulting in healthier trees. Additionally, smoke from fires overpowers the beetle’s pheromonal communication, thus impeding their spread.

Because of how widespread SPB distribution has become, eradication of the species is simply not possible. The main method employed to suppress invasions is the cutting and removal of infested trees. A more proactive method includes monitoring pines for the early infestations of SPB to enable a rapid response to the arrival of SPB; bringing us back to Minnewaska State Park Preserve. The Sam’s Point area of Minnewaska is home to the only dwarf pine ridges ecosystem in the world, making it a globally unique and rare site. Therefore, monitoring for the arrival of SPB is imperative for the preservation of this rare pitch pine barrens as well as more common pitch pine communities of Minnewaska.

Nick and trap

Entomologist Tom Schmeelk with the Department of Environmental Conservation (DEC) came to Minnewaska to hoist the traps and explain how they work. The traps used are Lindgren funnel traps, with a chain of funnels that mimics a tree stem. Several lures, or packets of pheromoneswere placed inside the trap which is then hung in a hardwood tree several feet off the ground and from the trunk. The lures utilized are frontalin, the sex pheromone secreted by females, and endo-brevicomin, the aggregation pheromone secreted by males. In addition, alpha-pinene was attached, a host volatile produced by stressed trees. The beetles are lured to the trap and funneled into a collection cup, the contents of which are sent to DEC to be checked for the presence of SPB.

For those concerned that the traps will attract beetles into the park that otherwise would’ve remained absent, rest assured that these are short-range traps that would only lure beetles within a few mile radius- meaning they only attract beetles already in the area. Being unaware of their presence in the park would be the much bigger risk to the park’s pine dominated ecosystems and all the species that depend on these, including the rare dwarf pines. Last year all the traps remained empty, let’s hope for the same this year!

Post by Sarantia Mitsinikos, Invasive Species Project Steward with SCA/Americorps/State Parks

Featured image: southern pine beetle, Steven Valley, Oregon Department of Agriculture, Bugwood.org

Invasive Species Spotlight – Elongate Hemlock Scale

Name: Elongate Hemlock Scale (Fiorinia externa Ferris)

Origin: Native to China and Japan and was first observed in New York City in 1905. It is believed that it was unintentionally introduced from Japan.

NYS Presence: Elongate hemlock scale (EHS) is present throughout the state, with the highest density within a 185 mile radius of New York City.

Identification: EHS is an armored insect most commonly found on the underside of hemlock needles. They show up as small (1.5-2 mm) and flat brown or white patches that hide the female and male insects, respectively. Underneath the brown scale, you may find the tiny yellow eggs.

Kristopher Abell, University of Massachusetts, Bugwood.org
Female EHS, look for small eggs, accessed from Kristopher Abell, University of Massachusetts, Bugwood.org

Life Cycle: “Crawlers” hatch from eggs under the female scale and emerge in the spring and summer. At this point they are mobile and can crawl to a new needle or be transported by wind or birds. Once they find a suitable site for feeding, they burrow under the waxy cuticle of the needle for protection, and insert their feeding tube into the mesophyll cells of the needle, just under the epidermis or surface layer of cells on the needs. The females will never leave this site as they go through their three stages of development. The males, however, will emerge from their five stages of development as winged adults. They will fly to a mature female, mate, and die without ever feeding. EHS overwinters either as fertilized females or eggs (typically 16-20 are laid). (Jill Sidebottom, Elongate Hemlock Scale, ncsu.edu).

Damage Pennsylvania Department of Conservation and Natural Resources -ugwood.org
EHS damage, photo accessed from Pennsylvania Department of Conservation and Natural Resources – Forestry , Bugwood.org

As EHS feeds on the hemlock needs they remove the plant’s nutrients, the needles take on a yellow color as they dry out and drop, leading to branch dieback and ultimately death in as little as ten years.

Control: One option of control is to remove highly infested trees. EHS can also be controlled chemically. The two most consistent chemical controls for EHS are Safari (a neonicotinoid) and Talus (an insect growth regulator). Safari is also used to control hemlock wooly adelgid, another invasive pest from Japan that often appears alongside EHS as white wooly ovisacs on the underside of hemlock needles. EHS can also be treated with biological agents, such as the parasitic wasp Encarsia citrina, and predatory beetles like the twice-stabbed ladybird beetle, Chilocorus stigma and Microweisea misella (Mark S. McClure, The Connecticut Agricultural Experiment Station). These biological controls have provided inconsistent results and are also susceptible to pesticides, so pesticide should be applied with that in mind. To report sightings of EHS in New York State Parks, visit  iMap Invasives or for other questions regarding invasives, email the Invasive Species Management Team at invasives@parks.ny.gov

The Invasive Species Management Team consists of Strike Teams and Forest Health Specialists. Strike Teams travel statewide for various invasive plant removal projects. Forest Health Specialists travel statewide as well, monitoring trees for the presence of forest pests like EHS and HWA among others.

Post by Sarantia Mitsinikos, Invasive Species Project Steward

Featured image photo by Irene Brenner

Invasive Species Spotlight – Leafy Spurge

Name: Leafy Spurge (Euphorbia esula)

Origin: Eurasia

NYS Presence: Leafy spurge has been identified in more than 15 counties across the state. It is found in grasslands, meadows, and riparian areas.

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Yellow-green leafy spurge plants in a field, photo by Leslie J. Mehrhoff, University of Connecticut, assessed from Bugwood.org

Species Profile: Leafy spurge is a perennial plant that spreads by both seed and its extensive root system. These roots have little pink buds that produce new shoots or roots. The root system can reach depths of 30 feet into the soil, making it a tough invasive to control.The leaves are narrow and linear with lengths as long as 4 inches. They are arranged alternately on the pale green stems of the plant.

Euphorbia esula
A yellow-green leafy spurge flower, photo by Matt Lavin from Bozeman, Montana, USA, accessed from Wikicommons

Two key characteristics to look for when trying to identify leafy spurge are:

  1. the plant’s tiny yellowish-green flowers, which grow in groups of three. Each one is enclosed by a pair of heart-shaped bracts (leaflike structure beneath the flower). Flowering begins in mid-May and will in some cases last until mid-Autumn.
  2. The second is the white, milky sap within the plant. Any stem or leave breakage will result in the release of this sap. There are a number of similar species of spurge species in the state, some which are also non-native and invasive.
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Leafy spurge plants, photo by Leslie J. Mehrhoff, University of Connecticut, accessed from Bugwood.org

The leafy spurge’s ability to spread at a fast pace make this invasive plant highly competitive. Dense stands will often smother or shade out other native species, therefore decreasing biodiversity. This species is a threat to native grasslands, meadows, and agricultural lands. Although cattle are not particularly fond of leafy spurge, sheep and goats have been known to snack on it and spread the seeds around in the process.

Resources:

New York Invasive Species leafy spurge

Colorado Department of Agriculture Leafy spurge identification and management

Featured image: Matt Lavin from Bozeman, Montana, USA, accessed from Wikicommons

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

Featured image: Antefixus21, accessed from Flicker