OCCA’s Terrestrial Invasive Species Guide

The Asian long-horned beetle (ALB) threatens urban and suburban shade trees and recreational and forest resources valued at hundreds of billions of dollars. While the Asian long-horned beetle has largely been confined to urban and suburban parts of the state, this species could have significant impacts on our upstate forests should it spread further. The beetle could impact industries such as maple syrup production and hardwood lumber processing, nurseries and tourism.

The emerald ash borer (EAB) is an invasive beetle to eastern Asia that kills all species of ash trees in North America, and has caused severe economic and ecological damage. It was first detected near Detroit in 2002, and has now spread to 28 states, the District of Columbia, and two Canadian provinces. Ash mortality is 100% near Detroit and is widespread in all the affected areas. Since the establishment of EAB in New York State we have seen economic impacts in forests where ash is a common timber species and in urban areas where ash are frequently planted as street trees.

The hemlock woolly adelgid (HWA), is an exotic pest native to Asia and western North America.  It was first described in western North America in 1924 and first reported in the eastern United States in 1951 near Richmond, VA.  This pest is now spreading through eastern forests at an alarming rate, and has the potential to remove a major component of these forests that is important in maintaining clean water and providing valuable habitat for myriad wildlife.  This pest is now found in at least 19 states, and Otsego County stands at the crossroads of the current invasion spreading north into the Adirondacks.  It is currently found on only a handful of sites in Otsego County, but surveys and programs are being done to determine the extent of the invasion.

Spotted lanternflies (SLF) are both destructive and disruptive pests. They feed on a variety of plant species, including important crops such as grapes, apples, blueberries, hops, and forest trees like maples. Their feeding behavior can weaken host plants, making them more susceptible to secondary infections and mold growth.

In addition to being destructive, SLFs can be quite disruptive. They often occupy various surfaces and may bump into or land on people while outdoors, although they do not bite or sting. While feeding, they excrete a sugary liquid called honeydew, which drips onto whatever is below them. This sticky substance attracts ants, flies, bees, and wasps and promotes mold growth. Lanternflies are fast but somewhat clumsy when flying and hopping, which can interrupt outdoor activities.

Native to eastern Asia, the spotted lanternfly was first discovered in the United States in southeastern Pennsylvania in 2014 and has since spread rapidly. They easily hitchhike on vehicles and will lay their eggs on almost any surface from late summer through fall. If you are in an area known for spotted lanternflies, be sure to inspect your vehicle thoroughly before heading home and consider taking it to a car wash.

Japanese Knotweed is not just any plant. It's a true survivor, thriving in conditions that would challenge most other plants, such as disturbed areas, roadsides, and even shaded, high-salinity, high-temperature, and drought-prone environments. This adaptability is what makes Japanese Knotweed such a formidable invader, demanding our attention for its management.

The primary objective in controlling Japanese knotweed is eliminating the rhizome system. Rhizomes are creeping underground stems that give rise to new shoots and roots. Small stands may be killed by repeated cutting, but this treatment must be repeated six times or more per season for many years. Pulling up the plants increases the risk of spreading knotweed because small pieces of root left in the soil can start a new colony. Another strategy is to smother the plants with heavy plastic or other material heavy enough to prevent the plants from growing through.

Garlic mustard, originally from Europe and Asia, was introduced to North America in the mid-1800s for its herbal and medicinal qualities.

Garlic Mustard is a biannual with a two-year life cycle; one plant can produce more than 7,000 seeds before dying. It emerges before most native plants and gains a foothold in early spring. By the time native species are ready to grow, garlic mustard has blocked their sunlight and outcompeted them for moisture and vital nutrients.

Your role in removing garlic mustard is crucial. The ultimate goal is to prevent seed development and spread. The best way to achieve this is by manually pulling the whole plant. After you have pulled the plants, bag them up and throw them out with your garbage; do not compost.

Wild parsnip resembles cultivated parsnip and belongs to the Apiaceae family. It likely escaped from gardens. The plant has yellow flowers that bloom in clusters from June to mid-July. After seeding, it dies but leaves a stalk that remains through winter. Its seeds can last in the soil for up to four years.

This invasive plant thrives in disturbed areas, especially along field and meadow edges. Once established, it spreads quickly.

While the roots are edible, the leaves, stems, and flowers contain a chemical that can cause a severe skin reaction when exposed to sunlight. This reaction, called phytophotodermatitis, can cause burning, rashes, blistering, and skin discoloration lasting up to two years. If you contact wild parsnip sap, cover the area and wash it with warm water and mild soap immediately. The skin will be sensitive for about eight hours.

To control small infestations, remove plants manually. Cut the root one inch below the ground or pull them up before they seed. If they have seeded, collect and destroy the seeds. For small areas, cut the tops and bag them in clear plastic to decompose.

Lonicera morrowii, Lonicera tatarica, and Lonicera maackii are similar-looking shrubs that grow between 6 and 15 feet tall. Lonicera japonica, however, is a woody vine that can reach 30 feet. All these species have egg-shaped leaves that grow opposite each other on hollow stems. Invasive honeysuckles flower from May to June, producing fragrant tubular flowers which can be creamy white, crimson, or various shades in between. L. morrowii and L. tatarica produce small red berries from mid-summer to early fall. L. maackii has dark red berries that ripen in late fall, while L. japonica produces dark purple or black berries in the fall.

In New York, you can find both invasive and native honeysuckles. To tell them apart, look at the stems: invasive species have hollow stems, while native species have solid stems.

These invasive honeysuckles can harm natural areas. They grow in dense thickets, leaf out early, and stay green longer than most other shrubs. This blocks sunlight, moisture, and nutrients from reaching other plants. Birds eat the fruits and spread the seeds to new locations.

If you find small plants early enough, you can pull them out by hand. In open spaces, prescribed burns can help control their growth. It's best to remove these plants before they produce berries in late summer or early fall to stop the spread of seeds.