You’ve no doubt heard that the emerald ash borer (EAB), that invasive little insect that devours and destroys ash trees, officially made its way to Nebraska last June. It’s got a lot of people concerned, and for good reason.
Infestations move through areas quickly, killing about 70 percent of unprotected ash trees within four years of initial discovery. Nebraska’s community tree canopy – large shade providing trees – has already shrunk by 50 percent since the 1960s and 70s, thanks to Dutch elm disease. With EAB, one million more trees are currently at-risk.
The tiny troublemakers are typically present and active from May through August. That’s why it’s important those with at-risk ash trees take action now – not only to save their trees, but also to prevent the collateral damage that weakened trees pose to power lines and property.
Treatment is only recommended if EAB has been found within 15 miles of your location. If the insect is not that close, treating your tree may be an unnecessary expense, with chemicals used doing more harm than good. Known infested counties within OPPD’s service territory include Cass, Dodge, Douglas, Sarpy and Washington.
Viability of tree
A healthy tree will respond better to treatments and better handle the potential damage treatments can cause. Your tree is likely healthy if it doesn’t have insect or trunk damage; is located where the soil is not disturbed by traffic, trenching or utility lines; has a history of being properly watered; and has a full canopy with lots of leaves.
To prevent EAB, healthy trees should be treated every year or two by a certified arborist. Some options for trees of all sizes include trunk injections and basal trunk sprays, soil drenches and granules, implants, bark and foliage sprays. Here’s a treatment timeline:
- April (or fall, but not as effective) – soil drenches with imidacloprid
- Mid-May – bark sprays with bifenthrin, cyfluthrin or permethrin
- Mid-May through early June – soil drenches with dinotefuran
- Mid-May through early June – **trunk injections and implants
- Mid-May through early June – **basal trunk sprays with dinotefuran
**Applied only by professionals.
More tree diversity needed
Magnifying the EAB problem in Nebraska is that fact that we don’t have enough tree diversity. Ash trees have become one of Nebraska’s most commonly planted replacement trees – not only here, but across the country. The species is part of a small club of overly planted trees, which leaves our tree canopy vulnerable to the next bug or disease that enters our area.
Plant it forward
Whether you are planting new trees or replacement trees, the Nebraska Forest Service (NFS) and OPPD encourage diversity as part of the Plant it Forward campaign. Foresters have helped develop lists of trees to help homeowners pick the right tree for the right location. You can read more here.
NFS and the University of Nebraska-Lincoln have also put together an EAB fact sheet to provide more information for homeowners. If you have questions, email firstname.lastname@example.org or call OPPD Forestry at 402-536-4131.