An insect that kills ash trees
Emerald Ash Borer is an invasive species from Asia that attacks all ash species that grow in South Dakota. The larvae of the beetle destroy the vascular system of the tree causing dieback and death. Trees infested with the beetle have no natural defenses to the insect and will die within 3-5 years of the initial attack. Trees can die within a year where the insect is established and insect population is high.
High-value ash trees require treatment for prevention
All species of ash trees are highly susceptible to the Emerald Ash Borer and require either a soil applied or trunk-injected treatment to prevent infestation by EAB. By the time an ash tree shows obvious damage, it is usually too late to treat for EAB. However, preventive treatment can protect and save your ash tree.
What to look for
• Early fall coloration.
• Sparse leaves and tree canopy dieback.
• Woodpecker feeding.
• New branches sprouting from trunk.
• D-shaped holes in the bark showing where adult borers have exited.
• Hollow galleries underneath the bark.
• Decline in entire groups of ash trees.
EAB moves through communities quickly and with devastation
As of February 1, 2017 EAB has not been found in South Dakota. The spread of EAB will depend on people moving the beetle around, not its natural progression. It is possible that even if EAB is found in a SD city soon, it could take years with proper management before it reaches
• Insect larvae hatch from eggs deposited by beetles in bark crevices.
• Larvae chew through the bark and begin feeding on the tree interior.
• Feeding is complete in fall and larvae remain in the tree through winter.
• Adult beetles emerge late May to mid-August.
Treatment and Prevention
There are currently two options available for protection against the Emerald Ash Borer:
• A soil-applied systemic treatment.
– Application is yearly.
• A trunk injection systemic treatment
– Application every other year.
• Treatment timelines are dependent on your tree, landscape, infestation levels, and time of season.