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Larch / Tamarack > Needles fall off / needles missing

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  • Image: Fall Needle drop 1
    Credit: M. Grabowski, University Of Minnesota
  • Image: Fall Needle drop 2

    Credit: M. Grabowski, University Of Minnesota

  • Image: Fall Needle drop 3

    Credit: M. Grabowski, University Of Minnesota

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green arrowFall Needle drop

  • Deciduous needles turn yellow and fall off in autumn
  • Not insect or disease related, normal for larch trees
  • New needles emerge in spring
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  • Image: Larch needle cast 1
    Credit: John Hopkins, Natural Resources Canada, Canadian Forest Service
  • Image: Larch needle cast 2

    Credit: J. Schwandt, USDA Forest Service, Bugwood.org

  • Image: Larch needle cast 3

    Credit: K.Gibson, USDA Forest Service, Bugwood.org

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green arrowLarch needle cast
Meria laricis

  • First see yellow spots or bands on needles that turn reddish brown
  • Next entire needles turn yellow than reddish brown and fall off
  • Disease appears suddenly in wet spring weather
  • Not serious in mature trees but can kill seedlings
  • Currently found in WI, status in MN unknown
  • More information on Larch needle cast...
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  • Image: Eastern spruce dwarf mistletoe 1
    Credit: J.O'brien, USDA FS, Bugwood.org
  • Image: Eastern spruce dwarf mistletoe 2

    Credit: J.O'brien, USDA FS, Bugwood.org

  • Image: Eastern spruce dwarf mistletoe 3

    Credit: J.O'brien, USDA FS, Bugwood.org

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green arrowEastern dwarf mistletoe
Arceuthobium pusillum

  • Witches’ brooms, a clump of small weak branches arising from one point on a larger branch, form in infected trees
  • Needles within the witches’ broom remain green, needles on the rest of the tree yellow and fall off, typically from the top of the tree down
  • Short (1/2 to 1 inch) brown to orange dwarf mistletoe stalks can be seen during the growing season but fall off after seed dispersal in August or September; this occurs only after 4 to 5 years of infection
  • Common only on tamarack near infected black spruce in northern Minnesota
  • More information on Eastern dwarf mistletoe...
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  • Image: Tomentosus root rot 1
    Credit: USDA Forest Service, Bugwood.org
  • Image: Tomentosus root rot 2

    Credit: USDA Forest Service, Bugwood.org

  • Image: Tomentosus root rot 3

    Credit: USDA Forest Service, Bugwood.org

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green arrowTomentosus root rot
Onnia tomentosa

  • Heartwood of infected roots and trunks is initially reddish brown
  • As infection continues white pocket rot develops; decayed wood has elongated pockets or pits, and may appear honeycomb-like in cross section
  • Infected trees have reduced growth and thin canopies, produce large amounts of cones and eventually die
  • Infected trees frequently break or lodge during storms
  • Mushrooms that are velvety brown above and porous and buff colored below appear around the base of the tree in late summer
  • More information on Tomentosus root rot...

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