For the second straight year, the St. Clair Region Conservation Authority (SCRCA) has partnered with the Ministry of Natural Resources and Forestry (MNRF) to monitor nitidulid beetles (also known as sap or picnic beetles) that transmit the pathogenic fungus that causes oak wilt.
In 2019, samples were initially shipped to the Ministry of Natural Resources and Forestry lab in Sault Ste. Marie and later to Natural Resources Canada for DNA testing. The testing involved separating the insects from the trap fluids and running two separate DNA tests on the insects. The first identified the species of the insects present in the sample while the second test looked to see if the fungus was on the beetles. Testing was also completed on the solution in which the insects were trapped to look for traces of the oak wilt fungus.
“The final results have not been released as of yet. We hope to hear something in the next few weeks,” explained Tim Payne, Manager of Forestry with the SCRCA. “We need to remain vigilant with monitoring and tree maintenance practices if we are going to be able to defend against its spread into Ontario.”
Oak wilt is a disease that has impacted oak tree populations throughout the United States and concerns are growing about the possibility of its entry into Canada.
As its name would suggest, the oak wilt fungus primarily targets oak trees. The fungus is transferred to the trees by nitidulid beetles or when an infected oak’s root system grafts with another. The fungus causes the cycling of water and nutrients to become restricted leading to the eventual death of the tree.
Two baited traps have been set-up in St. Clair Township to attract Nitidulid beetles. Staff collect the insects every two weeks and send them to the MNRF for Oak Wilt testing.
Baited traps have been set up in St. Clair Township to attract the beetles. In addition, the 2020 program also includes a “wounding” exercise. Wounding involves drilling a hole directly into the tree bark to expose the tree’s sap. Staff will collect the insects attracted to the wound and test them for the oak wilt fungus.
“The wounding exercise will also allow us to identify a time frame for when the beetles are active, and determine which sap beetles are most attracted to our oaks,” continued Payne. “This can help us prepare proper management programs.”
Ten oak trees were “wounded” as part of the 2020 monitoring program. Insects attracted to the oak tree sap will be collected and sent to the MNRF for testing.
The monitoring program began in May and will continue until mid-July. For more information, contact Tim Payne, SCRCA Manager of Forestry at [email protected] or (519) 245-3710 Ext. 224.
