For more on Cottonwood diseases click on this picture and read more.
Cottonwoods are in the poplar family and often grow to be very large trees.  Cottonwoods are fast growing trees that have a huge drawback that often keeps homeowners from planting them.  And that problem just so happens to be in their name.  The cotton that they produce can be overwhelming when they become larger.  Lots of homeowners complain that there yards look like they are covered with snow in the summer becuase the cotton gets so thick.
Despite the cotton problem cottonwood trees are harmed by many insects.  So many in fact that I found a really good link that is below that can help you further if you think your cottonwood tree is diseased and may need some attention.
The most destructive insects to the cottonwood trees are cottonwood leaf beetles (shown top right).  They infest cottonwood tree and start to eat off all of the leaves.  There are many borers that affect the cottonwood trees.  Results of what these borers do to a tree can be found on the right side of this page. 
Other insects that harm cottonwood trees are leaf curl mites, viceroy butterflies, tentmakers, leaf hoppers and many other insects.  Four different fungus rots affect the cottonwood tree. There are also several leaf associated diseases that harm the cottonwood trees as well.  Here are some things to look for in your cottonwood tree:

  • Die back in sections or large limbs
  • Holes in trunk
  • Woodpeckers are present (they eat the larvae)
  • Severe leaf damage
  • Large infestations noticeable
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Fagaceae family
Emerald Ash Borer, dutch elm disease, maple wilt, disease control, tree treatments
Common Name: Bur Oak

Scientific name: Quercus macrocarpa
Leaves: 3-6" long, 2-5" Broad, Variable in shape, lobed margins
Bark: Medium gray color and rugged texture
Height: 100" max
Spread: 50-70'
General info: Large deciduous tree native to North America and can live up to 400 years.  Trunk can grow to sizes exceeding 10' in diameter.  This tree is often confused with white oak as it is very similar in many ways.  Long taproot makes this tree very drought resistant. 

Pests and diseases: Bur oak blight and two-lined chestnut borer are the two major issues that bur oaks face in Minnesota.
Common Name: Cottonwood

Scientific name: Populus deltoides
Leaves: Large deltiod shaped, 1.5-4" long, 1.5-4" broad, serrated
Bark: Smooth silvery white when small, dark gray and deeply fissured on old trees
Height: 60'-130' tall at max
Spread: 40-80'
General info: A native tree to the United states.  This fast growing, water loving tree can grow to extreme sizes at maturity.  With trunk diameters often over 8' in diameter and often multi-trunked.  This species is well know to make a mess with its excessive cottony seed drop.

Pests and diseases: Cottonwood borer is the main pest of these trees
Common Name: Pin Oak

Scientific name: Quercus palustris
Leaves: 2-6" long, 2-4.5" Broad. With 5-7 lobes, each lobe having 5-7 teeth
Bark: Rough dark gray bark at maturity
Height: 60-70' max
Spread: 40'
General info: Pin oaks are a generally short lived oak tree only living to 120 years. Unlike other oaks this tree does not have a strong taproot and is commonly a wetland tree.  Residentially, this tree is very tolerant of transplant, grows fast and has great pollution tolerance.

Pests and diseases: Iron chlorosis is often the worst issue when planted residentially.
Common Name: Red Oak

Scientific name: Quercus rubra
Leaves: Alternate, 7-9 lobed, oblong ovate to oblong. 5-10" long 4-6" broad
Bark: Dark reddish gray brown, broad thin rounded ridges, scaly.
Height: 90-140' max. 
Spread: 50'
General info: These trees are know to exceptionally fast growing trees in optimal conditions.  Can grow to the age of 500 years old.  Grow upright and trunk does not exceed 3' in diameter often.  Normally found near water sources and are often found in forests of similar species.

Pests and diseases: Oak wilt is to most common disease known to this tree.  Other insects include two-lined chestnut borer and red oak borer.
Common Name: Swamp Oak

Scientific name: Quercus bicolor
Leaves: Broad oviod 4.5-7" long, 3-4" broad, Shallow lobed, 5-7 lobes on each side
Bark: Texture similar to white oak, less rugged, gray brown bark
Height: 60-80' max. 
Spread: 30-40'
General info: Not a common tree of Minnesota but is being introduced as there are many threats to other oak trees.  These trees are great at adapting to different climates and soil textures.  A fairly fast growing medium sized shade tree.

Pests and diseases: Two-lined chestnut borer is a major pest of this tree.
Common Name: White Oak

Scientific name: Quercus alba
Leaves: 5-8.5" long, 2.5-4.5" broad, Lobed and ovalite leaves.
Bark: Light to dark gray in color, shallow fissured and scaly.
Height: 80-100' max. 
Spread: 60-100'
General info: White oaks are one of the oldest trees in Minnesota.  They are known to live up to 450 year of age in the wild.  This slow growing tree often grows in forests with similar trees.  Tree doesn't produce acorns until 50 years of age. Often sought after for its beautiful wood which is used in a variety of different woodworking projects.

Pests and diseases: Two-lined chestnut borer is the main pest of this species locally.