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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Evergreen Trees and Shrubs > Fir > Needles drop prematurely

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Fir > Needles > Needles drop prematurely

1 of 4
  • Broom rust 1
  • Broom rust 2
  • Broom rust 3

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
2 of 4
  • Rhizosphaera needle cast 1
  • Rhizosphaera needle cast 2

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...
3 of 4
  • Balsam needle midge 1
  • Balsam needle midge 2
  • Balsam needle midge 3

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
4 of 4
  • Fir needle rusts 1
  • Fir needle rusts 2
  • Fir needle rusts 3

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...

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