Need help with pine blight problem - Ask Extension
I have a ponderosa pine with a blight problem. I believe it's red-band blight, I've treated the tree the last 3 years with copper fungicide and that s...
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Need help with pine blight problem #793338
Asked May 30, 2022, 3:36 PM EDT
I have a ponderosa pine with a blight problem. I believe it's red-band blight, I've treated the tree the last 3 years with copper fungicide and that seemed to help, except for this year. I've sprayed the tree 4 times already, at 1 week intervals, and the brown needles seem to keep growing (see pictures). The brown needles have a red band where the brown meets the green on each needle--see the needles at the top of "pine1.jpg".
Any suggestions on what else I can do?
Jefferson County Colorado
Expert Response
Hello Rob,
Thank you for your question and photos. The banding is more likely due to freeze/winter desiccation damage than a pathogen. Dothistroma (the red band pathogen) is very rare in our dry climate. We are always on the lookout for it, so consider submitting a sample to the Jeffco Plant Diagnostic Clinic for diagnosis ($7 fee for Jeffco residents).
References
Mari Hackbarth
Thank you for your question and photos. The banding is more likely due to freeze/winter desiccation damage than a pathogen. Dothistroma (the red band pathogen) is very rare in our dry climate. We are always on the lookout for it, so consider submitting a sample to the Jeffco Plant Diagnostic Clinic for diagnosis ($7 fee for Jeffco residents).
References
- Winter Browning of Evergreens https://planttalk.colostate.edu/topics/weeds-cultural-problems/2114-winter-browning-evergreens/
- Winter Drying https://extension.colostate.edu/topic-areas/yard-garden/winter-drying-is-a-likely-cause-of-brown-pine-needles/
- Winter Burn https://csfs.colostate.edu/2020/01/15/october-cold-snap-injures-ponderosa-pines-in-southeast-area/
- Dothistroma Needle Blight https://extension.psu.edu/red-band-dothistroma-needle-blight
Mari Hackbarth
