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A three pronged approach to understanding the defensive mechanisms in green ash (Fraxinus, pennsylvanica) resistant to EAB (Agrilus planipennis)

2018 | Jeanne Romero-Severson, PhD, University of Notre Dame

Imagine a tree that protects stream banks, shelters farms from wind and blowing snow, grows rapidly, thrives in urban settings, lives for over 100 years, tolerates cold, heat and salt, has few diseases or insect pests, and displays a beautifully shaped canopy with small seeds and handsome foliage. These are the ash trees native to America, primarily green ash and white ash and they are disappearing because of emerald ash borer (EAB), an insect accidentally imported from Asia. EAB is spreading rapidly across the United States, killing 98-100% of the ash trees it infests throughout forests, along rivers, in rural regions and in urban communities. Dead tree removal and insecticide treatments cost rural and urban communities over 1.7 billion dollars in 2011 alone and the cost continues to increase.

The good news is that a few green and white ash trees (<1%) survive for years after all other local ash trees have died. Scientists working for United States Forest Service and the University of Notre Dame have confirmed that most of these survivors have the ability to fight EAB attack and different trees use different defensive strategies. This grant from TREE Fund will enable this team of scientists to identify groups of chemical compounds that fight off EAB in individual trees and the genes that produce these compounds. This work will identify the best group of offspring from parent trees having the highest defensive responses.  

Increasing the rate at which naturally-occurring defensive traits in ash are identified decreases the time it takes to produce trees with enough resistance to survive in the wild. Within a few generations, the seed from these trees can be distributed throughout the Midwest to establish local seed orchards for restoration. This will reduce EAB from a deadly plague to a minor pest. The project relies on a team approach and wise use of multiple techniques including forest monitoring, tree propagation, applied entomology, a small dose of high tech analytical wizardry, tried and tested plant breeding techniques and a lot of hard work. The impact will be the return of American ash trees to the landscapes where they once grew, shading our rivers, beautifying our neighborhoods and lifting our hearts with the sight of their beautiful green foliage.

For more information on this project, contact the researcher via TREE Fund at

Need funding?

Applications for the Hyland R. Johns and UARF Research Grants, Ohio Chapter ISA Education Grant, and all scholarships are open January 15 through March 15.

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