Oak Wilt-like symptoms in Blanco, TX.
Diagnosing oak wilt properly is critical as a misdiagnoses can lead to a delayed response, or unnecessary stress with treatments in the absence of disease. Understanding recent stressors and the history of tree health on a property can help with determining why a tree is in decline. The leaves pictured are from a consultation and diagnosis in Blanco, Texas, where similar symptoms in leaves created a cause for concern.
What we observed during our consultation for oak wilt.
We witnessed stress and decline in a group of oak trees that according to the home owner, happened recently and rapidly. The consult was in October, following several dry months and the summer heat. Other tree species had also declined on the property, and Hypoxylon canker was present on several of the live oaks in decline. Neighboring live oaks nearest the trees in decline appeared healthy and without the questionable leaves. These trees also browned throughout their canopies, showing the lack of transpiration of water throughout.
What we concluded with our diagnosis for oak wilt.
With the information provided, including the timeline of decline and visible irregularities in the leaves, we concluded the trees in question had succumbed to drought stress and canker. Stress and browning throughout the canopy is more consistent with drought and can be seen in groups of trees responding to the stress event together and on the same timeline of decline. The irregular veining can also be common due to damage following freeze events, or in trees near fires and exposed to excessive heat.
What we recommended.
Following our diagnosis, we recommended removal of the dead trees and trees with Hypoxylon canker. Since the oak wilt pathogen can be challenging to diagnose in drought stressed areas, we always recommend watching neighboring tree health for any indication a systemic disease like oak wilt is present. This includes watching for symptomatic leaves and upper canopy losses that would be more in line with oak wilt, and show disease movement through root-graft.
Confirming an oak wilt diagnosis.
Oak wilt management can call for extensive plans, especially when diagnosed in tight communities, so getting the diagnosis correct is critical. When there are differences in diagnosis, or inconsistencies in what is being observed, diagnostic sampling and testing with the Texas A&M Forest Service diagnostic laboratory is an option to help provide clarity. These tests can create delays and may result in a false negative, but false positives are not possible meaning oak wilt is truly present and is a threat to neighboring trees requiring mitigation. Contact Oak Wilt Pros if you have any questions or concerns or would like to schedule a consultation for oak wilt.