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Northern Research Station
One Gifford Pinchot Drive
Madison, WI 53726
(608) 231-9318
(608) 231-9544 TTY/TDD

Emerald Ash Borer

Black Ash Submergence

Research Issue

[photo:] Technicians prepare to submerge black ash logBlack ash has special importance for American Indian and First Nations peoples in the Great Lakes and northeastern North America.  It has ring porous wood that allows layers of xylem to be easily separated and for centuries, has been used for making baskets. Emerald ash borer (EAB) was discovered in Detroit, Michigan in 2002, and has killed hundreds of millions of ash trees as it continues to spread across North America. It is threatening the ash resource including black ash and the indigenous cultures and traditions that rely on it. Submergence in water is a traditional method of holding black ash logs from the time they are cut until they are needed for basketmaking.  In this collaborative study, research scientists partnered with American Indian basket makers to determine whether submergence of black ash logs infested with EAB  would kill the insect while preserving wood properties sought for basketmaking. 

 Our Research

We evaluated the traditional practice of storing black ash logs submerged in water as a possible method for killing within-tree life stages of EAB while preserving the wood’s value for basketmaking. 

Black ash trees infested with overwintering EAB larvae and pre-pupae were felled and cut into 60-cm bolts in 2010 and in 2011, submerged in a river for different lengths of time, and following treatment were placed into rearing tubes to determine survival and adult emergence or were dissected within 24 hours to determine larval mortality, then pounded and peeled into splints to assess color and pliability. 

Expected Outcomes

These results will be useful to black ash harvesters and basketmakers as guidelines to help reduce the inadvertent spread of EAB, with all the threats that entails for their lives and livelihoods.  The process and results also may help inform EAB response planning at local to state and regional levels.  It demonstrates that a well-designed program, especially when undertaken in collaboration with tribes and basketmakers, offers the opportunity to reduce vectors of spread while supporting a key cultural practice for future generations.

Research Results

In 2010, EAB mortality was very low after 1 week of submergence in spring. Mortality increased with duration of submergence; however some larvae survived and adults emerged from logs submerged for up to 9 weeks. All larvae had died and no adults emerged from logs submerged for 10 weeks or longer. 

In 2011, mortality was very low for logs submerged in winter for up to 8 weeks.  Larvae apparently remained dormant within the saturated logs in cold water.  Mortality increased after 8 weeks when water temperatures began to warm, and all larvae had died and no adults emerged from logs submergence for 16 weeks or more.  After 6, 12, and 18 months of submergence, the outer rings of sapwood began to decay and crumbled off the log; however, interior rings of sapwood remained intact and pliable. 

For logs submerged in spring 2011, some EAB survived up to 9 weeks but all EAB larvae died after 13 weeks and no adults emerged from logs submerged for 14 weeks or more. 

Poland, Therese M.; Ciaramitaro, Tina M.; Emery, Marla R.; Crook, Damon J.; Pigeon, Ed; Pigeon, Angie 2015. Submergence of black ash logs to control emerald ash borer and preserve wood for American Indian basketmaking. Agricultural and Forest Entomology. 17(4): 412-420.

Research Participants

Principal Investigator

  • Therese M. Poland, US Forest Service- Northern Research Station Research Entomologist

Research Partners

Last Modified: 12/07/2017

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