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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Evergreen Trees and Shrubs > Pine > Dead or dying seedlings

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Pine > Seedlings > Dead or dying seedlings

1 of 5
  • Diplodia shoot blight 1
  • Diplodia shoot blight 2
  • Diplodia shoot blight 3

Diplodia shoot blight
Diplodia pinea

  • New needles are brown, short and often glued together with resin
  • Cankers are resin coated flattened areas on branches
  • Needles and branch beyond canker turn brown and dies
  • Tiny, black, pimple-like fungal structures on dead needles and pine cones
  • Infected shoots and dead branches occur throughout the tree but most commonly in lower canopy
  • Cankers and dead needles can appear rapidly after wounding from hail, drought or other stress
  • Olive to dark brown streaking in sapwood below cankers
  • Common on Austrian, red and Scots pine
  • More information on Diplodia shoot blight
2 of 5
  • White grubs 1
  • White grubs 2
  • White grubs 3

White grubs
Phyllophaga spp.

  • Wilted, dying or dead seedlings
  • Fibrous roots missing from affected seedlings
  • Common in grassy areas; all conifers affected
  • C-shaped white larva with brown head; conspicuous legs; grow to 1 inch long
  • More information on White grubs
3 of 5
  • Northern pine weevil 1
  • Northern pine weevil 2
  • Northern pine weevil 3

Northern pine weevil
Pissodes approximatus

  • Dead 2 – 4 year old seedlings
  • Attacks all pines, particularly seedlings with heavy grass competition
  • Larvae about 1/3 inch long, white and feed under bark
  • Cocoons made of wood chips (chip cocoons) found under bark
  • Adult weevils about 1/3 inch long, brown with small white spots and typical weevil "snout"
  • More information on Northern pine weevil
4 of 5
  • Sirococcus shoot blight 1
  • Sirococcus shoot blight 2
  • Sirococcus shoot blight 3

Sirococcus shoot blight
Sirococcus conigenus

  • Needles turn brown, wilt and droop
  • Young shoots wilt and curl into a shepherd's crook
  • Brown to black raised bumps can be seen on wilted needles and on shoots at the base of the needle in the fall or spring following the appearance of symptoms
  • Older needles remain unaffected
  • Common in cool, wet summers
  • Infection often starts in the lower branches and moves up
  • Common on red, jack and Scots pine; Austrian and eastern white pine are resistant
  • Also infects spruce, fir and larch
  • More information on Sirococcus shoot blight
5 of 5
  • Armillaria root rot 1
  • Armillaria root rot 2
  • Armillaria root rot 3

Armillaria root rot
Armillaria spp.

  • Infected trees have reduced growth, discolored needles, thin canopies; produce large amount of cones and eventually die
  • Flat white sheets of fungal growth (mycelial fans) between the bark and sapwood at the base of infected trees
  • Thick, black shoestring-like fungus can sometimes be seen under the bark at the root collar and in the soil near the base of the tree
  • Base of the tree may be encrusted in resin
  • Wood is decayed, white, soft and spongy, beginning with the roots and may extend from the base of the tree well up into the trunk
  • Trees frequently break or fall over in storms
  • Clusters of honey-colored mushrooms may grow at the base of the tree in fall
  • More information on Armillaria root rot

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