Emerald Ash Borer Ready to Kick Ash in Kansas
Emerald Ash Borer: Ready to Kick Ash in Kansas
Nicole Opbroek, Forest Health Specialist
Kansas Forest Service, Manhattan, Kansas
Emerald Ash Borer (EAB) was discovered in Wyandotte County at Wyandotte Lake in August 2012. This is the first identified infestation in Kansas. As of August 29, 2012, Wyandotte County was put under an emergency quarantine that will restrict regulated articles from being moved and hardwood firewood from leaving Wyandotte County. The purpose of the quarantine is to slow the spread of the beetle. The Kansas Forest Service participates in a multi-agency task force assembled to detect and manage this invasive threat to Kansas ash trees. Other cooperating members of the task force include U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) Plant Protection and Quarantine (PPQ), USDA Forest Service, the Kansas Department of Agriculture, and the Kansas State University Research and Extension.
What is at risk?
There are an estimated 56.1 million green and white ash trees in our rural and urban landscapes. Ash is our third most common tree species found in Kansas. Green ash is the most widely distributed of all the American ash species because it is hardy to the climatic extremes in the Great Plains. Often green or white ash species are the dominant tree in city street plantings, ornamentals, subdivisions, golf courses, and other municipal properties like parks. Green ash is commonly found along rivers and streams in our natural areas. The potential impact of emerald ash borer on forest biodiversity, wildlife habitats, quality of riparian areas, ash resources, and urban living will be profound if/when this pest becomes widely established in the state.
Where does EAB come from and how far has it spread?
The EAB is an exotic wood boring beetle that was introduced to North America from Asia. In 2002, it was first discovered in Detroit, Michigan. It was believed to have arrived via wood packing material in shipping crates. The initial introduction of EAB likely occurred in the early 1990’s. Since the 2002 discovery, it has been identified in the following states: Connecticut, Illinois, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Missouri, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, Wisconsin, and now Kansas. A federal quarantine is in place covering whole states or counties where EAB is present. In Kansas, further detection surveys are underway (September 2012) which will determine the quarantined counties. This beetle threatens our urban forests and natural areas by killing all North American ash species (Fraxinus sp.) and their cultivars. Over 25 million ash trees have been destroyed due to EAB.
What is the lifecycle of EAB and how does it kill ash trees?
EAB kills trees over a period of one to four years depending on the size and vigor of the tree. Adults are usually present during the summer months (May-August) depending on the weather patterns. A few weeks after eggs are deposited in crevices in the bark, they hatch and the larvae begin to chew through the outer bark to the phloem. It is the larval stage that does the damage. When feeding they begin forming S-shaped galleries (July-October) that expand as they grow. This feeding fatally disrupts the transport of water and nutrients from the roots to the crown of the tree. The larvae overwinter as prepupae in the sapwood and in the spring after a few weeks pupate and emerge as adults (May-June) creating a D-shaped exit hole. As adult beetles, they feed on the foliage during their 3-6 week lifespan, mate, and then the process begins again each year. One keynote: weather is a key player on timing for the beetle. For example: it is a warmer than usual year, then emergence and flight will occur earlier—like this spring of 2012.
What does EAB look like?
- Adult beetles are a rich metallic green in color, with a purple to reddish copper colored abdominal segments under the wings. The insect is approximately half an inch long and an eighth of an inch wide.
- Larvae are legless, with bell-shaped body segments that have a flattened appearance. They are creamy white in color and are found under the bark.
- When adult beetles emerge from the tree they leave distinctive D-shaped (half-moon shaped) exit holes in the outer bark of branches and the trunk. Their presence typically goes undetected until trees show symptoms of being infested.
What are the signs or symptoms of EAB?
- Canopy dieback: Starts from the top down and can occur until the tree is bare and heavily infested. Up to half of the tree’s branches can die back during the first year.
- Epicormic shoots: Sprouts grow from the roots and trunk as the tree tries to compensate for the loss of canopy below the level of infestation. The leaves are often larger than normal on these sprouts.
- Increased woodpecker activity: Birds peck while foraging creates larger holes when extracting insects.
- Bark splitting: Vertical fissures will appear when sprouts are present on the bark due to callous tissue formation. Galleries may be visible under the exposed bark split.
- Serpentine (S-shaped) galleries: Larval feeding creates tunnels that weave across the wood grain. Galleries will be packed with frass (mix of sawdust and excrement).
- D-shaped exit holes: Happens upon emergence of adult beetles.
How do EAB infestations spread?
EAB adults can fly at least a half a mile a year from the tree where they emerge. Thus, parks or natural areas that contain ash tree species greater than 5 miles from known EAB populations are projected to be approximately 10 years from EAB impact. It is generally recommended that if EAB is in your county or within 15 miles of, protection of ash trees should be started. This unfortunately cannot be said in confidence due to the difficultly in detecting low-level EAB populations and the high likelihood that EAB could spread further distances by people moving ash logs/tree parts, green ash lumber, composted and uncomposted chips of ash, ash firewood, or infested ash trees from nurseries. The simplest way to slow the spread of EAB is to not move these restricted articles.
What are treatment options?
Insecticide Options for Protecting Ash Trees from Emerald Ash Borer is a good publication on the various methods. In addition, the Purdue EAB Insecticide Product Guide discusses the most current options. Because pesticides need to be applied annually to every couple of years, they are best-used to protect high value trees for the life of that tree. A variety of professional-use products are available. For more information visit: www.emeraldashborer.info and click EAB Infested Trees or additional information can be found at: extension.entm.purdue.edu/EAB and click on management.
As a result of the infestation, concerned citizens whom seek to minimize economic, aesthetic, and environmental impact on your city’s urban woodlands and rural timberland are asked to be proactive.
- Familiarize yourself with the quarantine areas and state regulations.
- Identify and count your ash trees by a simple inventory and assess the health and condition on your property.
- Contact your local tree board or municipality to learn more about your Community Action Plan for treatment, removal, and replacement of infested trees.
- Preemptively remove ash trees in severe decline from any cause.
*Removal of damaged/defective ash trees or pruning during the winter months (November—February) should be done when EAB is dormant. When removing trees in a quarantined county and transporting to the nearest marshaling yard, whole ash trees (top, bowl, and stump) must be chipped to less than one inch in two dimensions. If ash logs are wanted for lumber or other uses outside the quarantined county, the bark and 1 inch of sapwood must be removed. REMEMBER that EAB does not cause any defects in the ash wood itself, so there are plenty of on-site uses if the trunks can be cut into useable products via portable mill.
- Start monitoring your ash trees for signs and symptoms of EAB this next growing season.
- Replace lost ash trees with a diversity of trees species appropriate for your landscape or site conditions.
Why Kansas EAB Quarantine?
Kansas implemented an emergency intrastate quarantine for Wyandotte County to prevent further spread of EAB in Kansas. The quarantine applies to any corporation, company, society, association, partnership, governmental agency, and any individual or combination of individuals, from moving regulated items from the quarantined area, except under specific conditions established in the quarantine order.
Regulated items under quarantine include the following:
- The EAB, (Agrilus planipennis [Coleoptera: Buprestidae]), in any living stage of development.
- Firewood of all hardwood (non-coniferous) species.
- Nursery stock of the genus Fraxinus (Ash).
- Green lumber of the genus Fraxinus (Ash).
- Other material living, dead, cut, or fallen, including logs, stumps, roots, branches, and composted and uncomposted chips of the genus Fraxinus (Ash).
- Any other article, product, or means of conveyance that an inspector determines presents a risk of spreading EAB and notifies the person in possession of the article, product, or means of conveyance that it is subject to the restrictions of the regulations.
The quarantine, effective as of August 29, 2012, will remain in effect for a period of 90 days or until rescinded or modified by order of Kansas Secretary of Agriculture Dale Rodman. http://www.ksda.gov/plant_protection/?cid=2023
(Lead agency) Kansas Department of Agriculture, 785.862.2180, if you suspect you have an EAB infestation
Kansas Forest Service office, 785.532.3300, or the local Kansas State Extension agent in your area
Kansas Department of Agriculture http://www.ksda.gov/plant_protection/content/379
Kansas Forest Service Forest Health http://www.kansasforests.org/programs/health/eab.shtml
National Emerald Ash Borer Website http://www.emeraldashborer.info