Category Archives: Cool Science

Hungry Hungry Caterpillars

Throughout much of New York State earlier this summer, fuzzy caterpillars were rampaging through natural forests and well-kept gardens alike. Maybe you noticed these bristly little critters wobbling along, or even had an itchy rash after touching their mildly stinging hairs!

These crazy caterpillars are Lymantria dispar, which you may have called gypsy moths in the past. Why not just call them gypsy moths? What is really in a name?

This is an exciting time as we wait to hear the new official common name for our moth, Lymantria dispar, but for this blog post we’ll call them L. dispar for short. Currently, the Entomological Society of America has is considering options for new names under the Better Common Names Project, in order to “bar names referencing ethnic or racial groups and names that might stoke fear.”

There is a plethora of fun characteristics for this moth which could apply to a new name. I personally vote for something akin to “Pricklecater,” “Blue-Red Spotted Messworm” or “Itchy Eww Moth.”

A L. dispar caterpillar up close.

Anyways… back to our story.

A native of Europe, L. dispar were accidentally released into the wild in 1869 and have since become “naturalized” in 19 Northeastern states. This means they have shoved their way into local food webs as they munch down on foliage then in turn become a tasty food source for birds, bugs, and other predators.

For the most part, they are active participants in the wonderous world of ecology. They are citizens playing their part in a complex and everchanging ecosystem. A single L. dispar caterpillar can eat about a square meter of plant material during its short lifetime, but one caterpillar doesn’t do too much damage.

The problem is that one female moth can lay more than 1,000 eggs in a single mass, which stick to the sides of trees, and are browish and gummy-looking.

That’s a lot of eggs!

The female moths, which are white, lay their egg masses on the sides of trees after mating. The masses are brownish and gummy in appearance.

Every 10 to 12 years, the L. dispar population explodes exponentially and hundreds of thousands of tiny caterpillars hatch in the spring. Once hatched, they use a strand of silk to “balloon” away on the wind until they find a newly leafing tree to eat and eat and eat.

To experience these numbers, I’d like you to imagine walking your favorite path in the woods. Shaded from the hot sun, you can hear the gentle pitter-patter of rain sprinkling down through the canopy. How peaceful… There is no better place in all the world on this cloudless day.

“Cloudless day? But isn’t it raining?” you ask.

Oh yes, something is raining down… but it’s not water.

Scientifically known as frass, this tiny spherical poop from thousands of very hungry caterpillars is dropping down onto your head and shoulders, as these little machines diligently convert the lush green leaves overhead into little brown balls of poo.

Not great. Pretty gross.

These baby caterpillars have small, young jaws, and prefer soft new budding leaves until they are old enough to chew tougher vegetation. While they prefer hardwood trees, they will eat more than 300 different plant species when hungry enough, stripping away all foliage until trees and bushes are left embarrassingly naked.

This can be a problem.

Caterpillar can strip away much of leaf material. Usually, trees can survive it, as long as it does not happen too many years in a row.

When deciduous trees like oak, birch and maple are eaten by caterpillars, they usually have enough stored energy to push out another set of leaves before the summer is through. It takes multiple years of defoliation to weaken these trees to the point of death. However evergreen trees cannot bounce back as quickly. Coniferous (evergreen) trees put lots of energy into their tough, thick, needle-like leaves, and will likely die if more than half of their needles are eaten.

Most years the caterpillars are fairly harmless, except during these incredibly destructive outbreaks which reoccur in a slow but disastrous cycle. Due to this pattern, L. dispar are considered cyclical pests.

In the adult stage L. dispar moths are not destructive at all, as they do not eat anything (no digestive system) and only live for a few days. The white fluffy females have pretty wings used for decoration rather than flying, and release a hormone into the air for male moths to find them. Females remain on the sides of trees as the males fly in search of the females’ scent.The female will lay fuzzy egg masses on whatever surface she’s near and the life cycle will begin again.

This is where we can take some control over the situation. By counting the egg masses in the wintertime, we can predict how many L. dispar caterpillars will hatch in the Spring and we can prepare a plan of defense. 

Natural Population Controls


While major L. dispar outbreaks can resemble a plague of locusts consuming everything in their path, nature often has a way of correcting imbalances. At low densities, vertebrate predators keep the population in check, but are ineffective at controlling massive numbers of prey. Bird bellies just aren’t big enough!

However, when L. dispar caterpillars are densely packed into one area, viruses and funguses can spread rapidly. These are naturally occurring diseases which are always present in the environment, but only take significant effect when populations are grossly out of control. Researchers have identified one virus specialized to L. dispar which kills 90 percent of infected caterpillars. This virus has since been converted into an effective treatment which brings the population down to healthy levels.

This natural method of population control is the preferred way to control the situation since it doesn’t harm any other species. However, this treatment must occur very soon after the caterpillars hatch, otherwise the damage will already be done.

These last few months we’ve seen many caterpillars eating their way through New York, and next year could be even worse in some places… or not. It all depends how well nature’s natural defenses have worked.

Measures are being taken at State Parks to perform egg mass surveys to try and predict next year’s population and prepare for any treatments accordingly. Let’s not repeat the summer of 1981 when 13 million acres of forest were defoliated! Our poor defenseless trees!


Post by Juliet Linzmeier, Student Conservation Association member, Invasive Species Unit, NYS Parks

Cover shot – A L. dispar caterpillar. All shots from NYS Parks.

A close-up of a female L. dispar moth.

Resources

DISCLAIMER: The following materials have not been updated on the new common name for L. dispar, and refer to this pest as “Gypsy Moth”.


Want to learn more about these moths and efforts to protect the forest? The DEC has great information here at Gypsy Moth – NYS Dept. of Environmental Conservation

Prefer watching videos? The DEC also did a 30-minute Facebook Live post, which covers the history, morphology, control methods, and more!


Empire State Native Pollinator Survey – You Can Help!

Summer is in full swing, with flowers blooming and bees buzzing. Our native pollinators, which also include flies, butterflies, and beetles, are an important part of New York’s ecosystems. They work hard to pollinate our trees, wildflowers, gardens, and crops. Some of these native pollinators appear to be declining. To learn more, scientists have been evaluating the populations of pollinators throughout New York as part of the four year Empire State Native Pollinator Survey (ESNPS).

The ESNPS is a project that aims to determine the distribution and conservation status of target pollinator species in New York. This project is made possible through work by both scientists conducting statewide surveys and community members submitting pollinator pictures and specimens they have observed.

In the last few years, zoologists with New York Natural Heritage Program (NYNHP) have visited more than 60 State Parks throughout New York State searching for a variety of target pollinator species. Community scientists have also been contributing their finds with photos added to the ESNPS iNaturalist project page.

More than 21,000 observations had been submitted to this multi-year project byMarch 2021, with the project constantly growing. These observations have been submitted by over 600 people and represent over 1,400 species. The Empire State Native Pollinator Survey is accepting photo submissions through September 2021 and you can help!

Be A Community Scientist

Do you want to help contribute to pollinator survey efforts? The project is accepting photo submissions through September 2021! Photographs can be submitted through the ESNPS iNaturalist project page or through the iNaturalist app after joining the project online. This can be a fun activity to do solo or with friends and family the next time you visit a State Park. Pollinators can be found in a variety of habitats – keep an eye out for wildflowers on warm and sunny days to see what you can find.  If you are able to snap some good pictures and upload them to iNaturalist, experts can help you identify the species you have found. It is a great way to learn, too.

What to Look For

Below are some pictures of the target species for this project that have been found in New York State Parks. New York’s pollinators have so much variety! These are just a few examples of what to look for and photograph.

Cuckoo Bee


One of the interesting bumble bees we have in New York is Fernald’s Cuckoo Bumble Bee (Bombus flavidus=fernaldae). Cuckoo bumble bees are a group of parasitic bees that are unable to collect pollen or raise young. These bees will take over the already established nests of other bumble bees by invading and incapacitating or killing the queen. The Cuckoo bumble bee then forces the workers to raise its young.

Fernald’s Cuckoo Bumble Bee (Bombus flavidus=fernaldae) Photo Kevin Hemeon

Bee Mimics

Look closely at the Bare-eyed Bee-mimic Fly (Mallota bautias) and Eastern Hornet Fly (Spilomyia longicornis); these are flies that are called bee mimics. Bee mimics can look very similar to bees, hornets, or wasps. Imitating insects with stingers is a defense mechanism for these harmless flies. 

Bare-eyed Bee-mimic Fly (Mallota bautias) Photo Paweł Pieluszyński
Eastern Hornet Fly (Spilomyia longicornis) Photo Laura Shappell
Greater Bee Fly (Bombylius major) Photo Alan Wells

Longhorn Beetles

The project is also interested in information on the 100 species of longhorn beetles. These beetles generally have very long antennae and come in a wide variation of colors and patterns. They too are pollinators.

Strangalepta Flower Longhorn Beetle (Strangalepta abbreviata) Photo Alan Wells
Banded Longhorn Beetle (Typocerus velutinus) Photo Alan Wells

Where Should I Look?

You can find native pollinators all over. State Parks have a great variety of natural habitats where you can find interesting pollinators. Sunny days with not too much wind are ideal. Some of the counties that would benefit from additional surveys are Chenango, Cortland, Fulton, Lewis, Montgomery, Orleans, Tioga, and Yates.

Look for flowers along trails through fields, meadows, dunes, forests, or even in marshes and stream sides if you kayak or canoe. Stop and look for a bit to see if any pollinators settle down on the flowers. Photograph from a distance first and then try to move in for some close-ups. The insects are often so intent on feeding that they don’t fly away.

If you can help, sign up for the Empire Pollinator Survey ESNPS iNaturalist project page and submit your photos on that project page or the APP before Sept. 30, 2021. The results from the project are anticipated to be available in spring 2022.

Post by Ashley Ballou, Zoologist, NY Natural Heritage Program  www.nynhp.org

Resources

Read more about State Parks and our efforts with pollinators in previous posts in the NYS Parks Blog.

Protecting Pollinators

Across New York, State Parks staff is working hard to help support the diverse populations of pollinators from bees to butterflies, beetles, wasps, and more.  Here’s a sample of the pollinator protection projects going on this year in State Parks. Rockefeller State Park Preserve Wild Bees Photo Exhibit Working from their photographs from both Rockefeller … Continue reading Protecting Pollinators

State Parks Strengthens Niagara River Island Ecosystem

Just upriver in Erie County from Niagara Falls State Park lies New York State’s third largest island. Home to more than 20,000 people and split by Interstate-190, Grand Island is 28 square miles and divides the Niagara River into east and west branches.

Industry and commerce dominated this river and its shoreline for more than a century, leaving a legacy of water pollution, fish unsafe to eat, and loss of wildlife habitat so extreme that in 1987 the U.S. Environmental Protection Agency (EPA) declared the entire 36-mile river an Area of Concern.

That federal listing set the stage for years of remediation efforts by New York State to clean up the river and shoreline. And now, it has led to State Parks, working with several partners, to begin the next chapter in healing the river – the restoration of several wetland areas of habitat along Grand Island critical for many fish and bird species that rely on the river for survival.

Grand Island is in the Niagara River between Buffalo and Niagara Falls.

These projects focus on two State Parks on the island – the 895-acre Buckhorn Island State Park on the northern tip, a nature preserve which has some of the island’s best remaining marshland wildlife habitat, and the more-developed, 950-acre Beaver Island State Park on the southern tip.

With funding support from the EPA under a plan finalized in 2018, Parks staff have finished two habitat restoration projects at Grand Island and two more are under way this season.

At Beaver Island in the south, offshore rocky reefs have been added in the river to an area called East River Marsh to protect the shoreline from further erosion caused by boat wakes and wind. Thousands of native plants have been planted by hand to provide important habitat for fish and other wildlife.

In the north, Buckhorn Island has one of the largest remaining cattail marshes on the Niagara River. At a place called Burnt Ship Creek, contractors hired by Parks have created open water channels and “potholes” in the marsh to provide pathways needed for fish such as Northern Pike to feed and spawn. The new open spaces also allow sheltered nesting sites for such secretive marsh birds as the threatened Least Bittern, which prompted the conservation group Ducks Unlimited to partner with State Parks for this restoration project.

Habitat restoration projects on Grand Island by New York State Parks and other entities are shown on this map. Buckhorn Island State Park is at the northern tip of the island, and Beaver Island State Park is at the southern tip.
Completed habitat restoration project at Burnt Ship Creek at the northern tip of Grand island near Buckhorn Island State Park.

This season, parks crews are working at a place called Grass Island, which is not actually an island at all, but rather an area of shallow water filled with cattails and other aquatic plants, both above the water and submerged. Sometimes also called Sunken Island, Grass Island is just east of Buckhorn Island State Park across from the city of Niagara Falls.

In addition to cattails and other plants visible above the water, Grass Island is also made up of many acres of submerged plants, predominantly a species known as water celery or American eel grass. This plant provides food and cover for several types of fish, including the Muskellunge, the state’s largest freshwater sportfish, which spawns among the eel grass each spring. The Upper Niagara River is one of state’s most important habitats for this fish.

Above the water, many species of waterfowl and marsh birds use the island for nesting, feeding and nighttime cover. Pied-billed Grebes, a threatened species in New York, nest and raise chicks there in the summer. During the fall migration of Purple Martins, the birds will roost in the cattails by the thousands.

Grass island, as seen in a drone photograph. On the above map, Grass Island is at the top right of Grand Island.

Together, Grass Island forms a 20-acre ecosystem designated as a protected wetland by the state Department of Environmental Conservation (DEC). While Grass Island provides some of the most important habitat in the Niagara River above the falls, this area has been steadily shrinking in recent decades due to wave erosion caused by boat wakes or wind. Between 2007 to 2018, Grass Island shrank by more than a third, losing an estimated 1.5 acres of its above-water vegetation.

Use the slider bar to show the decreasing size of Grass Island. The left image is from September 2018, while the right image was taken in August 2007.

This season at Grass Island, Parks contractors are constructing underwater rock reefs similar to those successfully constructed at East River Marsh. Once the reefs are finished, crews will add submerged tree trunks with the roots still attached (called rootwads) to provide underwater structure needed for good fish habitat. Also, large numbers of native wetland plants will be planted behind the protective rock reefs to expand the area with dense vegetation.

Also this summer, similar rock reefs, rootwads, woody material, and native plantings will be installed along the shoreline at Buckhorn Island State Park to restore and protect coastal wetlands. And finally, another similar project is in the works for the shoreline along the new West River Shoreline Trail at Buckhorn.

These projects join other ongoing conservation efforts at Grand Island being done by DEC, and the Buffalo-Niagara Waterkeeper, a not-for-profit conservation group. Find a FAQ on the projects here.

Buckhorn Island State Park is also a listed Bird Conservation Area, with its marsh providing important nesting habitat for threatened species such as Least Bittern, Northern Harrier and Sedge Wren. The marsh serves as a feeding, resting and breeding area for ducks, coots, moorhens, and rails. Common Tern find suitable habitat for foraging here. Additional birds of interest include a variety of species of ducks, herons, coots, moorhens, and rails. Spring and fall migrations along the Niagara River corridor can bring large numbers of gulls to this site.

Some of the birds of Grand Island known to be in the Bird Conservation Area.

Gorge-ous Gulls of the Niagara in Winter

The Niagara River is well-known as an international destination for its tremendous waterfalls, which form spectacular ice formations during the winter. Perhaps a lesser known fact, however, is that the river is also a critical haven for migrating birds during this time of the year. Gulls, in particular, are a common sight along the Niagara, … Continue reading Gorge-ous Gulls of the Niagara in Winter


Together, these wetland restoration projects at Grand Island aim to maintain and strengthen this urban island ecosystem in a river that fuels the spectacular waterfalls only a few miles away that draw millions of visitors each year.

If a visit to Niagara Falls is in the works, consider also making a trip to Buckhorn Island State Park and Beaver Island State Park, both of which have car-top boat launch sites, to see this part of Niagara River and witness some of the efforts to help restore it. Please remember that these are sensitive ecological areas and habitats for secretive wildlife, so be respectful and take care when visiting these special places.

As always, whenever hiking, or in this instance, more likely paddling, consider “Leave No Trace” principles to minimize your impact on the environment. Learn more on how to practice “Leave No Trace” by clicking on this previous post in the NYS Parks Blog.

Beaver Island State Park: This park has a half-mile sandy beach for swimming, adjacent 80-slip marina with both seasonal and transient boat slips, fishing access, car-top boat launch, multiple canoe/kayak launches, about four miles of bike and nature trails, nature center, playgrounds, picnic areas, athletic fields, horseshoe pits, an 18 hole championship disc golf course, an 18-hole championship golf course. In winter, visitors can snowmobile by permit, cross-country ski, snowshoe, sled or ice fish. Waterfowl hunting is allowed in-season by permit.

Also located in the park is the River Lea house and museum, home to the Grand Island Historical Society and built by William Cleveland Allen, cousin to Grover Cleveland who visited the family farm on several occasions.

Buckhorn Island State Park: For a wilder experience, try this less visited park, which is a nature preserve of marsh, meadows and woods that mark the last vestige of once vast marshlands and meadows that bordered the Niagara River. There are nearly two miles of nature trails for hiking, biking, and cross-country skiing. The preserve includes two launches for kayaks and canoes. There is ongoing restoration to re-establish wetland cover and water levels and increase the diversity of native flora and fauna. This effort aims to increase public access with more non-intrusive trails, overlooks and bird watching blinds.


Cover shot: A work barge involved in habitat restoration at Grass Island. All photos courtesy of NYS Parks.

Post by David Spiering, Great Lakes Habitat Restoration Coordinator, NYS Parks

State Parks Trails for All: Measuring Accessibility

For people with differing levels of physical ability, it can be difficult to know in advance whether a hiking trail might be too steep, too narrow, too soft, or otherwise not suitable.

Here at State Parks, we are working to help address that through something called the Universal Trail Assessment Process (UTAP). Developed in the 1990s by a Nevada-based company specializing in aiding differently abled people to engage in recreation, UTAP is a system of objective measurements taken at specific intervals along an unpaved trail to form an accurate picture of its difficulty, in terms of grade, width, surface firmness and cover.

UTAP is the creation of Beneficial Designs, whose founder Peter Axelson suffered a spinal injury in the mid-1970s. Axelson later went on to become a championship alpine adaptive skier and founded his company to design and fabricate adaptive recreational equipment for people with mobility impairments. The company also develops accessibility standards for ski areas, amusement parks, playgrounds and other outdoor recreation environments.

Parks is entering our third year of the UTAP program, having measured more than 19 miles of trails at 17 different State Parks in 2019 and 2020. It is a time consuming process done on foot with several hand tools, with measurements taken at least every 100 feet. That has meant nearly 1,200 individual measurement points have been recorded so far!

So if any hikers encounter Parks staff carrying a clinometer (a protractor-like device used to measure grade), a hand-held roller wheel (used to measure distance), a level, and a hand-held GPS unit (used to record locations), they have seen the UTAP process in action.

The trail measuring tools under the Universal Trail Assessment Program. (Photo credit – Beneficial Design)
Student Conservation Association member Tyler Stempsey measures trail accessibility at the Olana State Historic Site. (Photo credit – NYS Parks)

This year, a new wheeled “buggy” is being acquired by State Parks that will carry a laptop computer to make measurement recording faster. With the buggy, an entire mile of trail can be measured in about an hour, a big improvement over doing everything manually.

This work is being supported by a Recreational Trail Program (RTP) grant from 2019, with the project currently scheduled to run through 2022.

These thousands of measurements are meant to identify which Parks trails meet what is called Recreational Trail Accessibility Standards (RTAS), which State Parks adopted from the United States Access Board standards and United States Forest Service standards Trail Accessibility Guidelines. These standards set requirements for maximum trail steepness, width, surfaces, passing space, resting areas, trailheads, gates, and signage.

With such measurements, Parks will be able to publicize trails that already comply with RTAS and prioritize trail improvement projects that would increase trail compliance with RTAS.

A sample is shown here of how measurements and surface conditions developed through UTAP can be represented visually. This shows a steep pitch across a trail, called a cross slope, that results in a soft, damp trail surface with mud, a situation which would render that trail out of compliance with the RTAS requirements.

So far, trails identified as meeting these standards include the Upper Falls Lookout Trail at Letchworth State Park and the Awosting Falls Connector Trail at Minnewaska State Park Preserve.

There are also several trails that are close to meeting RTAS with minor modifications including: the Bog Trail at Chenango Valley State Park, the Beacon Hill Trail at Minnewaska State Park, the Bike Path at Schodack Island State Park, and the Green Lakes and Round Lakes Trail at Green Lakes State Park.

This map shows trails in State Park showing where UTAP measurements have been made. (Photo Credit – NYS Parks)

Work is currently under way to improve the Green Lakes trails (park is #3 on the map above) so it meets standards.

More information on the UTAP assessment process and standards specific to State Parks and the trails examined so far, as well as an interactive version the above map, can be found here.

Once the measurement data is compiled and finalized, Parks will be able to provide a listing of accessible trails, as well as focus future improvement efforts on trails close to meeting accessibility standards.

The data we are collecting will also allow Parks to create detailed trail access information signs, which would provide visitors at trailheads with vital information such as slope, surface cover, distance, clearance, and elevation gains.

An example of a trail sign based on measurements of grade and cross slope taken under the UTAP system. (Photo Credit – Beneficial Designs)

The goal of the UTAP program is to make Parks trails more inclusive to all, regardless of ability. If you have a favorite trail that could be assessed for accessibility, let us know in the comments!


Cover Shot – Parks staffer Sean Heaton assesses trails at Minekill State Park in Schoharie County. (Photo Credit – NYS Parks)

Post by Victoria Roberts, GIS/Accessible Trails Technician, NYS Parks

Wasp Warriors Aid Parks Against Insect Invaders

If you haven’t noticed, New York’s ash trees have been struggling lately. Over the last few years, they have been rapidly dying due to a little iridescently green insect: the emerald ash borer (EAB).

An invasive beetle native to parts of Asia and Russia, EAB was first discovered in New York in Cattaraugus County in 2009. It has since spread to 55 of New York’s 62 counties, decimating once thriving ash populations.

Since its discovery in southeast Michigan in 2002, EAB has spread into 35 states and the District of Columbia, killing tens of millions of ash trees in their wake.

EAB is widespread in the eastern U.S. as show in this USDA map. Each red dot represents an infested county and the blue line is a federal quarantine zone.

Emerald ash borers lay eggs between bark layers and in bark crevices on ash trees. Upon hatching, the larvae burrow through the bark and begin to feed on the tree’s living parts: the phloem and sapwood. The larval feeding creates galleries, which cut off the movement of nutrients throughout the tree. Eventually, as the infestation grows, the tree’s system of nutrient transport ceases to function, and the tree slowly starves and dies.

EAB larvae create S-shaped “galleries” where they feed just beneath the bark of an infested ash tree. Use the slider bar to explore the damage in this tree.

Ash trees are important for so many reasons. They provide cool shade in the summer heat, provide habitat for wildlife, and are a valuable source of timber and firewood. When large ash die, however, they can pose serious safety risks. Dead and dying trees often bring down powerlines along the road and cause blackouts.

In addition, many trails, campgrounds, parking lots and playgrounds are surrounded by ash that, once infested, become hazard trees that require removal. Parks’ staff must constantly monitor public use areas for the presence of dying trees that may pose a risk to patrons.

The fight to conserve ash has been an uphill battle. While pesticide treatments work, they only last a year or two before reapplication is necessary and also are too expensive to use everywhere. Statewide quarantines and public education have helped slow the spread, but these little beetles can fly over a mile and lay up to 200 eggs in a lifetime, making containment difficult.

This chart shows the lifecycle of the EAB. (Photo credit – Cornell University)
State Parks staff at Jacques Cartier State Park peel back bark from an infested ash tree to reveal the EAB damage. (Photo credit- Aaron Hemminway, NYS Parks biologist)

You may be thinking “what can be done?!” Well with National Invasive Species Awareness Week coming May 17-23, an update from State Parks is timely.

Luckily, we may finally have a cost-effective, sustainable, and chemical-free solution to the problem. For the second year in a row, the state Office of Parks, Recreation and Historic Preservation and the U.S. Department of Agriculture (USDA) are partnering to release three species of predatory wasps – known ecologically as biological controls or parasitoids – to battle EAB in select state parks.

These tiny warriors are heavily studied little predators from the EAB’s home countries which prey only on these beetles and pose no risk to our native ecosystem. (And don’t worry. These wasps don’t sting and are no threat to people).

The females of these species attack ash borers in the early stages of their life cycle. These three wasps were chosen because they each have slightly different ways of tackling EAB, making them a more effective as a group.

Here, let’s meet our winged team.

Tetrastichus planipennisi

Tetrastichus planipennisi females lay eggs inside of EAB larvae, where the parasitoid larvae grow and eventually kill their host. They are used to protect smaller ash trees in particular, and they originate in China.


Oobius agrili

Oobius agrili lay eggs inside EAB eggs, where the parasitic wasp larvae hatch, grow, and kill the host EAB egg. These wasps are all female, so they reproduce asexually. They also originate in China.


Spathius galinae

Spathius galinae lay eggs outside of EAB larvae; when they hatch, Spathius feed on the EAB larvae, killing it. These wasps are best at helping larger ash trees, and are collected in the Russian Far East.


Last year, 11 State Parks received about 40,000 Tetrastichus wasps: Rockland Lake in Rockland County; Harriman and Bear Mountain in Rockland and Orange counties; Minekill in Schoharie County; Beaver Island and Buckhorn Island in Erie County; Clay Pit Ponds in Staten Island; Lakeside Beach in Orleans County; Golden Hill in Niagara County; Southwick Beach in Jefferson County; and Point Au Roche in Clinton County.

Starting this month, Jacques Cartier State Park in St. Lawrence County and Ganondagan State Historic Site in Ontario County will be added to that list. All three wasp species will be deployed, with an expected total of more than 50,000 wasps. All the wasps used are reared in a lab in Michigan, where they are shipped to New York and other states where USDA is coordinating its EAB biocontrol program.

For the wasps to be successful here, they need to find the beetle in its early life stages. In New York, the emerald ash borer generally begins to lay eggs in the summer; however, many larvae overwinter inside of ash trees, and are thus readily available as food for the parasitoids in the spring.

Parks staff introduces the wasps into infested ash trees through three methods:


  • Ash bolts are small sections of ash (think small ash logs slightly larger than cans of soup) that house mature parasitoid larvae. They are attached to infested ash trees using twine or zip ties. When the larvae mature, they leave the bolts and find EAB larvae to feed on within the ash stand.
Ash bolts are attached to infested trees with zip ties or twine, and are marked with flagging so they can be easily found. Please don’t disturb or tamper with the bolts if you come across them!

  • Plastic cups containing adult parasitoids arrive on-site ready for distribution. The cups simply need to be opened, inverted and tapped gently against the trunks of infested trees.
Adult parasitoids arrive in plastic cups, ready for release.
  • Oobinators are used less frequently and only for the delivery of Oobius agrili. They are small, plastic pill bottles with a screen over the open end that can be attached to trees with zip ties or twine. They contain a sheet of paper with parasitized EAB eggs. Once mature, Oobius will hatch and escape through the screen.
Oobinators are hung upside down, to allow mature parasitoids to escape. Photo credit: USDA

While out exploring NYS Parks, you may see these “ash bolts” or “Oobinators” attached to trees. They are often marked with flagging for easy identification. While it may be tempting to try to get a closer look at these woodland wasp homes, it is important to let the parasitoids grow and feed uninterrupted,  to give them the best possible chance of survival.

While parasitoid releases may be new to New York State Parks, USDA has been conducting releases throughout the country for several years. Subsequent studies indicate that that wasps are surviving and are feeding on the EAB.

Studies have also shown that the Tetrastichus wasps in particular can eliminate up to 85 percent of EAB larvae in ash saplings. (Duane et al., 2017)

These are promising results which suggest if parasitoid wasps can be reared in abundance, they may offer crucial protection to the next generation of ash trees. It is important to keep in mind, however, that success will not happen overnight. Wasps need to find enough EAB to build up their populations to sustainable levels and it takes time to see results, even if wasp populations are doing well. Parasitoids also will most likely not save most larger ash, but they can help manage EAB populations so smaller ash trees can have a chance grow and hopefully reproduce.

Parks is thrilled to partner with USDA in this important endeavor to protect our forests. You also can join in the effort by reporting emerald ash borer sightings or suspected damage to the iMapInvasives website or smartphone app. There is also a USDA online reporting form here.

Also, help stem the spread of EAB and other invasive forest pests by following state regulations that control the movement of untreated firewood, which can carry these invasive hitchhikers.

  • Untreated firewood may not be imported into NY from any other state or country.
  • Untreated firewood grown in NY may not be transported more than 50 miles (linear distance) from its source or origin unless it has been heat-treated to 71° C (160° F) for 75 minutes.
  • When transporting firewood, the following documentation is required:
    • If transporting untreated firewood cut for personal use (i.e. not for sale) you must fill out a Self-Issued Certificate of Origin (PDF).
    • If purchasing and transporting untreated firewood, it must have a receipt or label that identifies the firewood source. NOTE! Source is sometimes, but not always, the same as where it was purchased. Consumers need to use the source to determine how far the firewood may be transported.
    • If purchasing and transporting heat-treated firewood, it must have a receipt or label that says, “New York Approved Heat-Treated Firewood/Pest Free”. This is the producers’ declaration that the firewood meets New York’s heat-treatment requirements. Most “kiln-drying” processes meet the standard, but not all, so it is important to look for the appropriate label. Heat-treated firewood may be moved unrestricted.

Find out if your destination is within the 50-mile movement limit by using this interactive map from the state Department of Environmental Conservation.

Finally, if you encounter evidence of biocontrol release sites while out on State Parks trails, know that you are in the presence of these wasp warriors, engaged in a battle to save our beloved ash trees.

Above, Parks staff hang ash bolts and record release data used by USDA to measure the effectiveness of the project to combat the Emerald Ash Borer.


Cover shot – Emerald Ash Borer (Original Artwork – Juliet Linzmeier, Student Conservation Association member with NYS Parks) All other photo credited to NYS Parks unless otherwise noted.

Post by Sarah Travalio, Terrestrial Invasive Species and Biocontrol Coordinator, New York State Parks


Here are other easy tips that can make a big difference in helping stop the spread of all invasives:

  1. Clean, drain, and dry your watercraft and gear thoroughly to stop the spread of aquatic organisms.
  2. Plant only non-invasive plants in your garden, or even better, plant native plants. You can use the New York Flora Atlas to check which plants are native to New York.
  3. Clean your boots or your bike tires at the trailhead after hitting the trail – seeds of invasive plants can get stuck on your boots, clothes, or tires. You don’t want invasives in your yard or your other favorite hiking spots.
  4. Get involved – volunteer to help protect your local natural areas, join your local PRISM (Partnership for Regional Invasive Species Management) to stay informed, or become a citizen scientist by using iMapInvasives to report infestations of invasive species right from your smartphone.

Interested in taking a deep dive into research on the parasitoid battle against the EAB? Check out these scientific studies:

Jian J. Duan, Leah S. Bauer, Roy G. Van Driesche, Emerald ash borer biocontrol in ash saplings: The potential for early stage recovery of North American ash trees, Forest Ecology and Management, Volume 394, 2017, Pages 64-72, ISSN 0378-1127, https://doi.org/10.1016/j.foreco.2017.03.024.

Duan, Jian J., Leah S. Bauer, Kristopher J. Abell, Michael D. Ulyshen, and Roy G. Van Driesche. “Population dynamics of an invasive forest insect and associated natural enemies in the aftermath of invasion: implications for biological control.” Journal of Applied Ecology 52, no. 5 (2015): 1246-1254. https://doi.org/10.1111/1365-2664.12485

Jian J Duan, Roy G Van Driesche, Ryan S Crandall, Jonathan M Schmude, Claire E Rutledge, Benjamin H Slager, Juli R Gould, Joseph S Elkinton, Establishment and Early Impact of Spathius galinae (Hymenoptera: Braconidae) on Emerald Ash Borer (Coleoptera: Buprestidae) in the Northeastern United States, Journal of Economic Entomology, Volume 112, Issue 5, October 2019, Pages 2121–2130, https://doi.org/10.1093/jee/toz159