Dothistroma Needle Blight in Montana
MODERATEFungus
Dothistroma Needle Blight is currently active in Montana. Watch your susceptible trees closely and act early.
About Dothistroma Needle Blight
A fungal disease of pines that causes premature needle loss and can significantly reduce growth and vigor. It affects many pine species but is especially damaging to Austrian, ponderosa, and Monterey pines. It has increased in severity with climate change.
Symptoms to watch for
Reddish-brown needle bands and spots, needle tips dying beyond the infection point while base stays green, premature needle drop starting on lower branches, thin canopy with only current-year needles retained
Trees at risk in Montana
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Treatment options
Copper Fungicide Spray
Application of copper-based fungicide in mid to late spring as new needles elongate and during rainy periods. May need repeated application in wet years.
Species Diversification
Replace highly susceptible pine species (Austrian pine) with less susceptible species or resistant varieties in landscape and windbreak plantings.
Recommended Products & Tools
Helpful supplies for managing Dothistroma Needle Blight. Always read and follow label directions, and confirm a diagnosis before treating.
Broad-spectrum protectant for many fungal leaf and bark diseases.
Preventive spray for needle cast, leaf spots, and blights.
Sharp, clean cuts to remove affected wood — a tree-care essential.
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Need help with Dothistroma Needle Blight in Montana?
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Browse all Montana arborists →Frequently asked questions
Is Dothistroma Needle Blight in Montana?
Dothistroma Needle Blight is currently active in Montana. Watch your susceptible trees closely and act early.
What does Dothistroma Needle Blight look like?
Reddish-brown needle bands and spots, needle tips dying beyond the infection point while base stays green, premature needle drop starting on lower branches, thin canopy with only current-year needles retained
What trees does Dothistroma Needle Blight affect in Montana?
It affects Ponderosa Pine, Eastern White Pine. Susceptibility varies by species.
How do I treat Dothistroma Needle Blight?
Options include: Copper Fungicide Spray, Species Diversification. Confirm the diagnosis before treating, and consider a certified arborist for high-value trees.