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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Evergreen Trees and Shrubs > Pine > Resin on trunk or branches

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Pine > Trunk/Branches > Resin on trunk or branches

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  • 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 7
  • Red turpentine beetle 1
  • Red turpentine beetle 2
  • Red turpentine beetle 3

Red turpentine beetle
Dendroctonus valens

  • Pitch tubes present, i.e. small masses of pitch at entry hole pitch tubes, on lower 3 feet of trunk
  • All pine species susceptible but favors stressed trees
  • Adults reddish-brown, ¼ - 3/8 of an inch long
3 of 7
  • White pine blister rust 1
  • White pine blister rust 2
  • White pine blister rust 3

White pine blister rust
Cronartium ribicola

  • All needles on one or several branches die and turn completely reddish-orange
  • Young cankers are elliptical, bark appears swollen and discolored yellowish orange
  • Older cankers exude large amounts of white sticky resin and have cracked bark
  • In early spring, orange-yellow blisters appear on the bark of cankers that are 2 or more years old
  • In summer, yellow-orange sticky liquid droplets form in cankers 3 years or older
  • Only white pine and other five needled pines can be infected
  • More information on White pine blister rust...
4 of 7
  • Ips bark beetles 1
  • Ips bark beetles 2
  • Ips bark beetles 3

Ips bark beetles
Ips spp..

  • Adults bore numerous holes less than 1/8 inch diameter in bark which can resemble being shot by a BB gun or shot gun
  • Entrance holes often have a reddish-brown, resin-soaked fine sawdust
  • Larvae feed under bark
  • Needles turn yellow and reddish-brown
  • Adults are dark brown to black and range in size from about 1/8 to ¼ of an inch long
  • Favors stressed pines of all species
  • More information on Ips bark beetles...
5 of 7
  • Pine root collar weevil 1
  • Pine root collar weevil 2
  • Pine root collar weevil 3

Pine root collar weevil
Hylobius radicis

  • Large amounts of pitch are exuded, darkening the root collar and nearby soil
  • Discolored needles, from yellow to reddish-brown on entire tree
  • Infested trees often tip due to feeding damage
  • Most pine attacked; prefers pine growing on sandy soils with heavy grass competition
  • Adults are ¼ inch long, reddish brown to black with whitish to yellowish spots (patches of scale); has conspicuous snout
  • Larvae about ⅓ inch long, whitish and grub-like
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  • Comandra 1
  • Sweetfern rust 2
  • Stalactiform 3

Comandra, Stalactiform or Sweetfern rust
Cronartium comandrae, Cronartium coleosporioides, and Cronartium comptoniae

  • When severe, canopy is thin, has poor growth, needles yellow, turn brown and die
  • On young stems or branches, infection may appear as a swollen, elliptical area
  • Infection develops into a long, flattened, resin soaked canker on the main trunk
  • Sweetfern rust cankers frequently occur near the soil level and grow up to 6 ft. long
  • Stalactiform rust cankers grow up to 25 ft. long along the main trunk
  • Comandra rust cankers occur on the main trunk and rarely grow over 4 ft. long
  • Ridges of wound wood may be present along edges of the canker
  • Pale yellow blisters of powdery spores break through cracks in bark in spring, sticky orange drops form along canker edges in late summer to fall
  • On young stems or branches, infection may appear as a swollen, elliptical area
  • Jack and ponderosa pine most severely affected, but many 2-3 needle pines are susceptible
  • Differentiation between the 3 species is most accurate with a lab analysis
  • More information on Comandra, Stalactiform or Sweetfern rust...
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  • Heterobasidion root disease and butt rot 1
  • Heterobasidion root disease and butt rot 2
  • Heterobasidion root disease and butt rot 3

Heterobasidion root disease and butt rot
Heterobasidion irregulare (previously known as H. annosum)

  • Slow growth, thin canopy, and discolored needles in severely infected trees
  • Resin soaked bark at base of tree
  • Sapwood of roots and butt discolored brown
  • Groups of infected trees commonly found in area where trees have been removed
  • Wood decays with a stringy white rot
  • Trees eventually die, windthrow common
  • Popcorn like white fungal structures that grow into leathery fungal conk, white to reddish brown above, cream colored with multiple pores below
  • Fungal conks common on cut stumps but often rare on infected trees
  • Infects most pines and other conifers
  • Not yet identified in Minnesota; if found, call Minnesota Dept. of Agriculture at 651-201-6684 or 1-888-545-6684
  • More information on Heterobasidion root disease and butt rot...

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