You may remember reading about the arrival of the Emerald Ash Borer (EAB), first in the state, and more recently in the St. Louis region. In March 2013, the City included an informational flyer on the EAB in the monthly utility bills. In the two years since, the State of Missouri and local arborists and horticulturists have reconsidered their recommendations on how to and whether or not to treat local trees infested with the EAB.
The Back Story: The EAB is an exotic, invasive, wood-boring beetle that infests and kills ash trees. The adult beetle is dark metallic green, with a bullet-shaped body that is about one-half inch long and one-eighth inch wide. The larvae (the immature stage) are flat, creamy-white grubs with distinct bell-shaped body segments. Adult beetles are usually seen from mid-May through July on or near ash trees. Larvae are found under the bark of ash trees during the remaining months of the year. The native range of EAB is eastern Russia, northern China, and Korea.
Human Transportation: EAB adults generally fly less than a half mile to mate and lay eggs on ash trees, making the natural spread of this pest relatively slow. Humans, however, can move the EAB long distances inadvertently in a short period of time. EAB can hitchhike under the bark of ash firewood, nursery stock, logs, and lumber, emerging from these materials to start an infestation in a new area.
What’s Being Done: To read more about what the Missouri Department of Conversation is doing about this and what they are recommending, please visit their Website here: http://extension.missouri.edu/treepests/home.aspx. There are several informational articles in the right-hand navigation on this page, including: “New EAB Management Guide for Homeowners.”
In Kirkwood: Originally, the recommendation from the MDC was to remove ash trees before they were infected because the consensus was that all ash trees would eventually become infected. Taking down a tree after it has died is expensive because it would be too brittle to climb and would require machinery. The MDC also said two years ago that all available treatments were expensive. In the past two years, however, a new injectable treatment has been developed that is safer for the environment and will last three years, making it an affordable choice.
City Trees: The City has received a second TRIM (Tree Resource Improvement and Maintenance) grant to track City street trees in right-of-way areas, which will help us identify where ash trees are located. Ash trees help with storm water run-off, so the City wants to keep as many of them in the ROW areas as possible. The City will therefore be treating many of its own ash trees but also gradually taking out unhealthy or untreatable ones. Kirkwood Parks and Recreation Horticulturist Pete Laufersweiler has been trained and certified in the Arborjet injectable treatment system that will be used in Kirkwood’s parks.
There are two chemicals the City can use to treat EAB. The Ima-Jet system is the less expensive option, costing about $10 to $20 per tree, depending on the tree’s size. It gives about 18 months of control, meaning if conditions are right and it is injected properly, the treated tree could last for two growing seasons. However, it is less effective in the second year. This is a proactive treatment that is used prior to infestations.
The other option is Tree-Age, which offers good control for two years. The treatment cost per tree ranges from $20 to $60, depending, again, on the tree’s size. This is a restricted-use chemical and can only be purchased and applied by licensed certified pesticide applicators in the State of Missouri. As the pest pressure dies down from EAB over time, it may be possible to get control for more than two years, but that will not happen until the EAB infestation reaches its peak in about 12 years.
What You Can Do: First, make an assessment of the trees on your property to determine if you have any ash trees (see photo at right of an ash tree’s leaves). Next, determine if your ash trees are of high value or lower value. Here is a page on the MDC Website that will help with that: http://extension.missouri.edu/treepests/EABhomeowners.aspx. If you have ash trees that you want to save, the final step would be to find an arborist who can treat your tree(s).
Please Don’t Move Firewood! If you go camping this summer or fall, please don’t take any firewood with you, and don’t bring any back home with you. Use the wood at your campsite, and don’t bring any extra home. This will help to slow the spread of this pest.