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Protect Ash Now from Emerald Ash Borer

If you have ash trees in your landscape you consider to be important and you wish to protect from the Emerald Ash Borer insect, a Purdue University expert recommended you do it soon.

Dr. Cliff Sadof, Purdue Entomologist, recommended insecticide applications for EAB by May 15. "Homeowner products can be used by do-it-yourselfers to protect trees effectively up to about 15” Diameter Breast Height (4½ feet up)." He emphasized that diameter refers to the width of the tree, not to be confused with circumference, which measures the total length around the trunk of the tree (a circular measurement).

Protection products available to homeowners typically contain either imidacloprid or dinotefuran. Additionally, one product contains a combination of imidacloprid and clothianidin. Depending on the product, the application may be either a soil drench (applied by bucket around base of tree), a basal bark spray or applied via granules. Homeowner prevention measures should be utilized annually to preserve those ash trees you want to protect the most.

Professionals have products that get into the tree more quickly and can protect trees for up to two years. Sadof added that recent research suggests that some of those applications can offer efficacy for up to three years. Engaging the services of a professional is recommended for larger trees.

EAB was first discovered in 2002 in southeast Michigan and Windsor, Ontario.

According to the Emerald Ash Borer Information Network (see link below):

  • As of October 2018, EAB is now found in 35 states, and the Canadian provinces of Ontario, Quebec, New Brunswick, Nova Scotia and Manitoba.
  • Since its discovery, EAB has killed hundreds of millions of ash trees in North America; caused regulatory agencies and the USDA to enforce quarantines and fines to prevent potentially infested ash trees, logs or hardwood firewood from moving out of areas where EAB occurs; and cost municipalities, property owners, nursery operators and forest products industries hundreds of millions of dollars.

Trees offer many benefits to homeowners, and among them are increased property values, shading and cooling for the house, and increased air quality. Trees benefit municipalities by reducing stormwater runoff. Sadof said that an 18” diameter ash tree will absorb an average of 2500 gallons of water over the course of a year.

People can help minimize the spread of EAB by not moving firewood.

Now, nearly 20 years after EAB’s first discovery, most ash trees in northern Indiana are already dead or dying. As homeowners look to replant trees, consider a diversity of species in your yard. Monocultures – where one species dominates an area – are more prone to attack and devastation by pests.

For neighborhoods, communities or cities, it may pay to work together to explore group pricing for tree removal or professional treatment.

For much more information, including EAB identification and resources on management, visit Purdue’s EAB Web site at Access information from Emerald Ash Borer Information Network at

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