Extension > Garden > Diagnose a problem > What's wrong with my plant? > Evergreen Trees and Shrubs > Fir > Needles drop prematurely
Fir > Needles > Needles drop prematurely
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Broom rust
Melampsorella caryophyllacearum
- Witches' brooms, a clump of small weak branches arising from one point on a larger branch, form in infected trees
- Needles on brooms are pale green to yellow in summer
- Needles die and fall off in autumn, leaving a clump of bare branches in the winter
- Yellow to orange bumps form on needles within the witches' broom, and may release powdery orange fungal spores in summer
- The branch at the base of the broom may be unusually swollen or cracked
- Also infects chickweed, causing orange spots or blotches on leaves
- More information on Broom rust
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Rhizosphaera needle cast
Rhizosphaera pini
- Drooping, grayish-tan needles in late spring or early summer
- Needles at the branch tips remain green, while older needles closer to the trunk of the tree become discolored
- Tiny black dots can be seen with a hand lens on infected needles
- Discolored needles fall off mid-summer; tree looks thin and bare
- Damage typically starts on the lower branches and moves up the tree
- More information on Rhizosphaera needle cast
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Balsam needle midge
Paradiplosis tumifex
- Galls appear in June as swelling near the base of individual needles
- Galls initially green, and can turn needles yellow by mid-summer
- Infested needles can die and drop off in autumn
- Thin foliage, especially in upper crown; particularly apparent in small trees
- Adults are tiny, orange and mosquito-like
- More information on Balsam needle midge
- More information on Balsam needle midge
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Fir needle rusts
Fir-fern (Uredinopsis spp., Milesina spp.), Fir-fireweed (Pucciniastrum epilobii), Fir-blueberry (Pucciniastrum goeppertianum)
- Current year needles turn yellow and sometimes curl
- Diseased needles may turn brown and drop prematurely resulting in thin foliage
- White or yellow tube-shaped spore producing structures form on the underside of infected needles
- Difficult to distinguish between these diseases in the field; lab analysis often required
- Rust infection on nearby alternate host, fern, fireweed or blueberry may aid in diagnosis
- More information on Fir needle rusts
