Entomology Today Article: Study Finds Quarantines Remain Key Part of Emerald Ash Borer Control

Emerald ash borer (Agrilus planipennis) is one of the most invasive and destructive tree pests in North America. A new study using a pest dispersal model shows that optimal management strategies to protect urban ash trees in the U.S. from emerald ash borer include both quarantines and biological control—with greatest effectiveness reached when quarantines represent the majority of management resources. (Image by Marc DiGirolomo, USDA Forest Service)

REPRINT courtesy of Entomology Today, Research News. See original here: Quarantines Remain Key Part of Emerald Ash Borer Control, Study Finds

By Laurel Downs and Leigh Greenwood

Emerald ash borer (Agrilus planipennis) is one of the most invasive and destructive tree pests in North America. It continues to spread across the United States and Canada, killing over 90 percent of ash trees (Fraxinus spp.) within a few years of establishing in a new area and causing hundreds of millions in economic damage since its initial detection in 2002. Since ash trees are a dominant species in urban environments, the current and projected loss of ash trees in cities imposes exorbitant monetary costs and leads to significant negative impacts on human health and wellbeing.

Management efforts to control the spread of emerald ash borer (EAB) and eradicate the pest in infestation zones have proven difficult due to multiple factors such as natural spread of the insect as well as human behaviors that result in long-distance movements. To reduce long-distance movement of this insect and other forest pests that move in or on firewood, The Nature Conservancy has led the Don’t Move Firewood educational campaign since 2008. The U.S.-based landscape of firewood regulations—such as firewood quarantines that legally limit the inbound or outbound movement of firewood to protected or from regulated areas—has strong impacts on the types of outreach and messages that Don’t Move Firewood communicates to the firewood-using public.

Emma Hudgins, Ph.D.
Emma Hudgins, Ph.D.

In a study published in February in Conservation Science and Practice, researchers used a complex spatiotemporal model to determine optimal management strategies for emerald ash borer in urban areas. “Understanding how and when to manage is a difficult problem,” says lead researcher Emma Hudgins, Ph.D., “because management action at any one site has ripple effects onto other sites due to changes in dispersal and growth dynamics of the invasive species.” Hudgins, now a lecturer at the University of Melbourne in Australia, led the study while a postdoctoral fellow at Carleton University in Ottawa, Canada.

Hudgins and colleagues sought to explore optimization of EAB management in the face of a changing strategic landscape in the U.S. Management efforts have shifted in recent years from a heavy reliance on a federal domestic quarantine to a focus on biological control (or biocontrol) using introduced stingless parasitoid wasps that prey exclusively on EAB eggs and larvae. The United States Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) rescinded the federal domestic quarantine on EAB completely in January 2021, leaving state authorities with the decision to rescind, retain, or implement their own state-based quarantines.

U.S. federal authorities now allocate the bulk of EAB funding to biocontrol, which comes with its own complications. “Understanding management implications is especially complex with the advancement of biological control technology, where parasitoid species are released such that they themselves spread across an invaded range and control invasive species population densities,” Hudgins says. “Whether this decision was optimal to limit urban ash exposure was untested, and it could be leading to excess tree death.”

Closeup of the de-barked surface of an ash wood log, in which two long creamy white beelte larvae sit in carved out spaces, each with a sinuous path left behind them in the wood, filled with a light brown dusty substance.
(Photo credit: Nathan Siegert, USDA Forest Service) Since its arrival in North America, the emerald ash borer (Agrilus planipennis) has killed over 90 percent of ash trees within a few years of establishing in a new area. Its larvae feed on the inner bark and phloem of trees, leaving behind signature S-shaped galleries as shown here. A new study using a pest dispersal model shows that optimal management strategies to protect urban ash trees in the U.S. from emerald ash borer include both quarantines of wood from infested zones and biological control with parasitoid wasps—with greatest effectiveness reached when quarantines represent the majority of management resources.

To find what management strategies minimize urban tree mortality under the current budget, the researchers derived a pest dispersal model as a mixed-integer linear program integrated with biocontrol and quarantine measures that results in an optimal spatiotemporal pattern of pest control. They then compared their findings with conventional management methods and the current EAB control strategies under USDA APHIS.

According to the model, combining quarantines with biocontrol is the best way to save ash trees. “We discovered that our optimized EAB management strategies, which incorporated quarantines and biocontrol together, consistently outperformed sole reliance on biological control, with a protection of up to 1 million additional street trees and savings of $629 million [U.S.] in tree removal and replacement costs between now and 2050,” Hudgins says.

The model showed optimal strategies not only relied on quarantines in addition to biocontrol, but they performed best with an unexpectedly strong majority of the funding directed toward maintaining effective quarantines around city centers. The study’s authors found that, while any management strategy with at least 20 percent spent on quarantines worked relatively well, the best results were seen when 98-99 percent of the budget was spent on quarantine with only 1-2 percent spent on biological control with parasitoids.

Findings from the study indicate that a coherent and harmonized effort to implement or maintain domestic quarantines in the U.S. could go as far as to save a billion dollars over the next three decades if implemented in a way that considers human behavior and connectivity among urban centers.

As it stands now, however, the regulatory environment affecting firewood movement within the U.S. is inconsistent, with just 18 of 50 states currently holding a partial or full external quarantine applicable to the movement of firewood that is potentially infested with emerald ash borer, leaving the remaining states particularly vulnerable to new infestations.

A de-barked log of ash wood sits in grass, and a sinuous zig-zag path is visible on the surface of the wood.
(Photo credit: Nathan Siegert, USDA Forest Service)Since its arrival in North America, the emerald ash borer (Agrilus planipennis) has killed over 90 percent of ash trees within a few years of establishing in a new area. Its larvae feed on the inner bark and phloem of trees, leaving behind signature S-shaped galleries as shown here. A new study using a pest dispersal model shows that optimal management strategies to protect urban ash trees in the U.S. from emerald ash borer include both quarantines of wood from infested zones and biological control with parasitoid wasps—with greatest effectiveness reached when quarantines represent the majority of management resources.

One example of the current inconsistencies is the difference between Oregon and Washington’s regulations. There is no current firewood or EAB quarantine to regulate the entry of out-of-state firewood into Washington, while its neighbor to the south, Oregon, has both an external firewood quarantine prohibiting the entry of higher-risk firewood and an internal quarantine prohibiting the outbound movement of materials from the area surrounding the only known infestation of emerald ash borer in the western United States.

At The Nature Conservancy, we are confident that the long-distance spread of emerald ash borer can be significantly reduced with appropriate firewood quarantines and a well-informed public. We’re pleased to see that this important study supports what all of our Don’t Move Firewood campaign partners can agree on: The persistent effort to maintain firewood rules and regulations in the public’s eye can and does protect trees.

Hudgins and colleagues intend to adapt their optimization framework for other management issues and species of concern. As stated in the study, “A future goal of this framework is to apply it across pest species to determine if there is predictable spatial patterning in management best practices across species.”

The widespread utilization of their framework in urban and forest health management could deliver invaluable benefits, not only in dollars saved but in the quality of life for countless numbers of people and wildlife that rely on the shade, water quality, environment, and beauty found amidst healthy trees.

Read the journal article:Spread management priorities to limit emerald ash borer (Agrilus planipennis) impacts on United States street trees

THIS NEWS PAGE IS A REPRINT courtesy of Entomology Today, Research News. See original here: Quarantines Remain Key Part of Emerald Ash Borer Control, Study Finds

Disposing of Woody Storm Debris from Asian Longhorned Beetle Host Trees

Hurricane season is upon us. Please stay safe!

The following is an important Alert from our friends at USDA APHIS and Clemson University’s Department of Plant Industry regarding the South Carolina Asian Longhorned Beetle Eradication Program in light of Storm Idalia:

——— NOTICE ———-

If you live in Charleston/Dorchester counties in South Carolina and are in the Asian longhorned beetle (ALB) quarantine, please be safe through storm Idalia.

Please dispose of woody storm debris from ALB host trees at the Bees Ferry Road Convenience Center, 1344 Bees Ferry Road, 29414, or the Hollywood Convenience Center, 5305 Highway 165, 29449. Any wood debris half an inch or more in diameter is considered regulated material and must be disposed of properly. Doing this helps prevent spreading the insect to other areas.

>>See Here for the South Carolina ALB Regulatory Boundary<<

ALB host trees include all species of the following 12 genera: Ash, Birch, Elm, Golden raintree, Horsechestnut/buckeye, Katsura, London planetree/sycamore, Maple, Mimosa, Mountain ash, Poplar, and Willow. The ALB quarantine applies to the beetle and all its life stages, firewood of all hardwood species, green lumber, and other living, dead, cut, or fallen materials which may include nursery stock, logs, stumps, roots, branches, and debris half an inch or more in diameter of all ALB host trees.

If you have any questions, please call 843-973-8329.

For information on how best to protect yourself from high winds and flooding, please visit https://www.ready.gov/hurricanes.


Additional Web Resources:

REMINDER: Firewood, yard waste, and other wood and tree products could potentially contain beetles. Don’t take firewood from your backyard along with you when you go camping, fishing, or any activity where you might use firewood. Instead, buy local bundled firewood at or near your destination, or gather firewood on-site when permitted.

protect south carolina forests billboards


Top 5 Emerald Ash Borer Awareness Week Ideas for 2021

The emerald ash borer (EAB) is an invasive beetle that infests and kills ash trees in North America. Right now, the EAB is found across most of the Central and Eastern US, as well as increasingly the Great Plains and Southeastern states. Once a tree has been infested with emerald ash borer for several years, it is very difficult to save that particular tree- but if caught early enough, ash trees in yards, parks, and streets can usually be successfully treated and protected. To help your community successfully find emerald ash borer infestations before they get so severe that they cannot be treated, we need your help!

During Emerald Ash Borer Awareness Week (May 23- 29th, 2021) everyone is encouraged to take a few minutes to learn about the signs and symptoms of emerald ash borer infestation on ash trees, so that the infestations can be better managed by local tree professionals and foresters.

Here are our Top Five Resources for Emerald Ash Borer Awareness Week!

  1. Check out this short and awesome video on how to identify ash trees and damage from the emerald ash borer: Emerald Ash Borer ID Video
  2. Do you need some more technical handouts? Check out the this comprehensive Resource list here at EmeraldAshBorer.info Publications and Resources
  3. Looking for kid friendly EAB resources like a coloring page or a bug mask? Look through our awesome “For Kids” page! 
  4. Want something quick to download for a social media account? Here’s a fun banner that works well for Facebook, Twitter, and more: 
  5. Or do you just want it all? Take a look at our Emerald Ash Borer Awareness Week Toolkit, where we list all the Resources that we think can help you make it a successful week.

If you think you have found signs of emerald ash borer on your ash tree, click here to learn about how to report it in your state.

The best way to slow the spread of emerald ash borer and other forest pests is avoid moving firewood long distances. Instead, buy local firewood, buy heat treated certified firewood, or gather firewood on site when permitted.


(image credit for EAB image used in Facebook Advertisement, Spring 2018: Steven Valley, Oregon Department of Agriculture, Bugwood.org Image 5445431)

Federal Deregulation of Emerald Ash Borer

USDA APHIS published the final rule that will remove federal domestic EAB quarantine regulations on December 15th 2020, with the rule to take effect January 14 2021 (read the press release here). This action will generate two key changes that pertain to the movement of potentially EAB infested firewood. The first change is that no directly EAB-connected federal regulation will apply to firewood- however, keep in mind the other federal, state, tribal, and private regulations and rules that apply to firewood will remain. The second change is that the federal structure that allows for the certification of heat-treated firewood in EAB infested areas (compliance agreements) will no longer apply, and therefore certification programs will need to shift to rely on state-based compliance agreements or other types of verification.

To aid in the potential development of state-based firewood regulations and heat treatment certification programs, the National Plant Board proactively developed a comprehensive set of Firewood Guidelines. These guidelines are now available online, and they contain templates, research references, recommendations, and case studies that will help inform adaptive changes over time. You can find the National Plant Board Firewood Guidelines here.

The Don’t Move Firewood campaign is run by The Nature Conservancy to reduce the rate of spread- and thus mitigate the impacts- of forest pests across North America. The campaign is based on the concept that the pathway of firewood should be addressed holistically, and the specific pests that may be in or on firewood are secondary to the idea that firewood itself can pose a threat. The Don’t Move Firewood campaign has always provided outreach materials reflecting the focus on firewood, regardless of if it is from a defined area with a federally regulated pest (such as emerald ash borer, or Asian longhorned beetle) or not (such as goldspotted oak borer, or thousand cankers disease). Due to this focus, Don’t Move Firewood outreach activities after the federal deregulation of emerald ash borer will be largely unchanged- with the exception of updating all materials describing former federal EAB quarantine boundaries. In 2021, all states and provinces on the Firewood Map found on Don’t Move Firewood website will be revised to reflect the changes in the firewood regulation environment.

For more information that pertains to this process, please visit:








Published comments on the emerald ash borer deregulation proposal


This fall’s recent open comment period on the proposal to lift the federal quarantine on emerald ash borer brought in well over 140 comments, many of them from national, regional, or statewide groups. In order to facilitate finding and reading the comments that are most pertinent to our partners’ needs and interests, the staff at Don’t Move Firewood have created a linked list of comments sorted into broad groups. Please note this is NOT all the comments, and errors and omissions in this listing may exist. For the full and definitive list of all public comments, please visit Regulations.gov directly.

National or Large Regional Scope Groups:

State or Tribal Governments and Agencies:

National Private Industry Groups:

Other Groups:

Cleaning up tree debris in hurricane damaged areas

How to Keep Neighborhood Trees Healthy and Resilient in the Aftermath of Hurricanes

Hurricanes Harvey and Irma have been taking down countless trees in Texas, Florida, and all the states between them along the Gulf of Mexico. In the aftermath of severe storms like these, trees can get lots of attention and are pointed to as the cause of loss of power and damage to property. However, while some trees do come down in high wind and extreme weather events, the majority of healthy trees survive severe storms, buffer the high winds as the storms come ashore, absorb excess rainfall, and reduce localized flooding.

In the wake of these major storms, it is extremely important to remember that moving storm debris, limbs, and downed trees over long distances can inadvertently spread tree-killing insects to new places. Many areas affected by Hurricane Harvey and Irma are under quarantines that specifically prohibit the long-distance movement of tree-based storm debris (including debris that has been cut into pieces of firewood). These quarantines will depend on exact location, and may include restrictions in place for emerald ash borer, imported fire ants, giant african land snail, and citrus greening (Huanglongbing). The southeastern USA also has widespread infestations of laurel wilt, which is not under federal quarantine but can be transported on storm debris as well.

Storm debris from downed trees and branches should be disposed of using one of the following safer ways: brought to a local solid waste facility (i.e. landfill), brought to a licensed city composting facility, brought to a registered storm debris disposal yard (sometimes called a marshalling yard or area), or used on site for personal firewood. Consult local newspapers and storm information to find out which of the disposal options is best in your area as you get ready to clean up your property.

Tree damaged by Hurricane Harvey in Texas 2017: Flickr user Welscor, Creative Commons License

For future storm safety, it is especially important to remember that trees planted near homes and roads need to be properly pruned to minimize potential damage and failure, especially near power lines. When planting new trees, it is helpful to select a species that will not grow too tall and interfere with power lines to minimize future damage. As cities look to replant choosing the right tree and putting the right tree in the right place will create a more sustainable—and storm resistant—landscape for years to come.

Despite the damage trees can cause in extreme weather events, healthy trees in urban and suburban areas are important for a safer and cleaner urban infrastructure. Trees provide the many benefits to both people and wildlife in city settings:

  • Improving water quality by minimizing erosion, slowing the flow of precipitation, and minimizing flooding during heavy rain events
  • Mitigating climate change by removing carbon dioxide from the air, regulating local climate by lowering daily temperature variation, and reducing energy expenditure on heating and cooling
  • Providing shade and improving local air quality by removing air pollutants and producing oxygen
  • Creating valuable habitat for wildlife, and shade and a natural environment for city residents

For more information, we recommend visiting:

This blog is based on our popular 2012 blog, The Importance of Trees in Hurricane Sandy

Firewood from Pennsylvania to New Mexico

Dear Don’t Move Firewood,

I live in Albuquerque New Mexico and was planning to make a trip to Pittsburgh Pennsylvania. What if any, are the restrictions for moving a pickup load of Hickory, Oak, Cherry and Apple back to NM with me when I return? Does this require any special permit? I plan to use the wood for heat and smoking meat. 


Barbecue Lover

Dear Barbecue Lover,

Thank you for asking, as the answer to this is quite clear. It is illegal to move a truckload of cut loose firewood from Pennsylvania to New Mexico due to multiple federal quarantines pertaining to firewood and forest pests. There is no permit process that I know of for personal use firewood to be moved over this great of a distance, and across the two federal quarantine boundary areas. I would urge you not to take this firewood back to New Mexico for both legal, and ecological, reasons. I hope that instead, you can find a good local source of firewood within the state of New Mexico for your needs! —


The two most obvious quarantines you would be violating are:

– Emerald Ash Borer Quarantine or General Information

– European Gypsy Moth Quarantine or General Information


In conclusion- there are significant restrictions and you’d be violating the law, so you should not move firewood from PA to NM. Thank you!



What is a firewood quarantine?

When most people hear the word “Quarantine,” they think of isolating a person that’s sick with some dangerous, contagious disease. When we talk about a forest pest related quarantine, the underlying concept is the same– it is just that instead of not letting people move around, we’re often talking about not moving firewood around.


Quarantines that relate to forest pests can work two basic ways- (1) preventing potentially infested materials, like firewood, from moving out of an known infested area, or (2) preventatively designating areas where no potentially infested materials could be brought in at all. The official term for potentially contagious or infested materials (things like firewood, nursery trees, brush waste) is “regulated items,” and each forest pest has a different list of appropriate regulated items, according to how its specific life cycle works.


(1) Much like a human quarantine for a contagious illness keeps the infected person from exposing new groups of people to whatever they’ve got, the first kind of a forest pest quarantine keeps people from moving regulated items out of infested places and into uninfested locations where they could infest new groups of trees- like uninfested campgrounds, forests, or neighborhoods. In some cases, more than just firewood can spread forest pests, so a quarantine might include not just firewood, but also other regulated items like nursery trees (like emerald ash borer), or outdoor furniture (like spongy moth), or even outdoor potted plants (like imported fire ant.) One important caveat about quarantined areas is that while it might be technically legal to move materials from one side of a county or state to the other side, that action might still be spreading unwanted pests- so it is still not a good idea. Further, when it comes to forest pest quarantines, often the federal and state rules are different- and the more “strict” rules always apply first. For instance, even though both Western Massachusetts and the bottom half of New York are part of the large multistate quarantined region for emerald ash borer, due to New York State laws, it is still illegal for campers to bring untreated firewood from Western Massachusetts into New York State for their campfire.


(2) The second kind of quarantine is a more preventative measure, and it is called an External Quarantine. Instead of trying to keep current infestations in a confined area, an external quarantine is trying to preserve the health of the forests by blocking out any infested materials coming from elsewhere. For instance, Maine has an external quarantine that prohibits bringing any untreated firewood into the state of Maine, to protect their state’s very important timber resources from all possible forest pest threats.


For more information on the status of various forest pest quarantines in your area, please look up your state or province on our map.

Kiln Dried vs Heat Treated firewood

Packaged firewood comes in a lot of forms, and it is important for you to know the difference between kiln dried firewood and heat treated firewood.

Kiln dried firewood is firewood that has been dried out, for some unknown period of time at some unknown temperature, in a kiln. It is a term without a firm definition, and with no legal standing. Kilns used for kiln drying can be set to lots of different temperatures and they can dry wood out a little, or a lot, and still label the wood kiln dried. Kiln dried firewood is NOT acceptable to move around, because of huge variations in how long, and how hot, the firewood was treated. It is completely NOT a meaningful label when it comes to forest pests and diseases. You cannot, for instance, take firewood that is simply labeled “kiln dried” out of a quarantined area for emerald ash borer. That is illegal.

Heat treated firewood is different. The makers of heat treated firewood hold a legal compliance agreement that the firewood is heated to a certain core temperature and for a certain amount of time. The heat treatment standard that is used most often is for 60 minutes to 60 degrees Celcius (140 degrees Farenheit) because this is the approved heat treatment level for emerald ash borer. The majority of the time, heat treated firewood is considered OK to move if it is properly labeled as such. There is notably some variation in heat treated firewood and various state and federal regulations. For instance, the required heat treatment level for firewood entering the state of New York is higher (hotter and longer) than the heat treatment level for firewood leaving an emerald ash borer quarantine area. However, in most cases, firewood labeled with a USDA APHIS seal (like the sample shown below) is considered safe to move across jurisdictional boundaries.

And now you know!



Regulations in Tennessee

Sometimes, even the experts at Dear Don’t Move Firewood don’t have all the answers. Here’s our latest inquiry, with a guest answer from Tim Phelps at the Tennessee Division of Forestry.

Dear Don’t Move Firewood,

I understand that we should not move firewood where I live in Tennessee… I live in Knox County which has a quarantine, my family’s farm is in Union County which is not under quarantine at this time. The firewood there is free for my cutting. But, am I allowed to move firewood this far? Can I move it from county to county. Or is the ban only for moving firewood across state lines? Is it okay to move firewood from a non quarantined county to a quarantined county. The distance to move it would be under thirty miles. Is this too far? Should I look for a safe and affordable fuel wood source locally in Knoxville? This is sad that this is happening. Wood is how we heat our home and save money. Just looking for answers and some direction on what I should do.

Thanks, Robert in Tennessee

Dear Robert,

Thanks for your interest and willingness to go the extra mile to find the correct information regarding movement of firewood in and out of regulated areas in Tennessee. In general, the restrictions in Tennessee allow you to move firewood from a non-regulated county to a regulated county, but that material cannot come back out of the regulated county unless it meets certain requirements. Tennessee has firewood movement restrictions in several of its eastern counties of the state, not all – yet. The restrictions are in place based on the presence of either the Emerald Ash Borer (EAB) or Thousand Cankers Disease (TCD), or both. The counties you mentioned – Knox and Union – are among those that restrict the movement of firewood. Knox County because it has both EAB and TCD. Union County is also currently under quarantine, but only for TCD (as of August 15, 2011).

Because Knox has both, you can move firewood into that county from Union. However, because Union does not have EAB, you cannot move firewood from Knox to Union. This is indeed confusing, but it amplifies the point that firewood is a pathway for multiple threats and that we need to limit its movement if we stand any chance of slowing the spread of these insects and diseases.

The Tennessee Department of Agriculture has “Regulations in Plain Language” for both the EAB and TCD quarantines available on their website for further reference.



You may also call their Regulatory Services Division at 1-800-628-2631.

Thanks for asking!

Tim Phelps, Tennessee Division of Forestry.