Tree Wrapping / Sunscald
Colorado trees don’t always appreciate Colorado’s sunny winter days and can suffer from sunscald.
What to look for:
- Affected areas on south side of trees in direct sunlight
- Affected areas on north side of trees due to reflection of sun from nearby white or light-colored surfaces
- Affected areas begin by turning red, orange, or yellow
- Eventually leading to ugly cracking and scarring of bark
- Affected areas could turn red, orange, or yellow at first.
- This could lead to ugly cracking and scaring of the bark. In extreme cases, it poses a threat to the life of your trees.
The ideal treatment is tree-wrapping installed in November and removed in April.
Western Pine Beetle / IPS
These invasive insects embed themselves in the bark of stressed or recently planted pine and spruce trees.
What to look for:
- A collection of yellow- or red-like dust
- Fading tree color
- Woodpeckers, which use these insects as a food source
The ideal treatment window is March-April and July-August
Fire Blight
A bacterial disease that can kill branches or even whole plants, Fire Blight affects many members of the rose family and can be spread by pruning tools, insects, and more.
What to look for:
- Large dead branches
- Leaves that turn yellow, brown, then black
- Branches that curl at the end (creating a Shepherd’s Crook)
The ideal treatment window is March-June, however pruning during dormant months can help avoid the spread of bacteria.
Boring Insects
Boring insects typically develop underneath the bark of trees and shrubs, and injured trees or those under stress are more susceptible to them.
What to look for:
- Major limb dieback
- Holes around tree wounds
The ideal treatment window is April-June
Scale
Scale generally develops on the limbs and trunks of many woody trees and shrubs, generally in the shape of an oyster shell with a black, brown, or gray color.
What to look for:
- Twig and branch dieback
- Honeydew—a sticky, glossy substance—underneath the tree
The ideal treatment window is April-June
Emerald Ash Borer
Considered the most destructive tree insect pest in North America, Emerald Ash Borer kills millions of trees.
What to look for:
- Sparse foliage or canopy dying from the top down
- “D” shaped exit holes in the bark
- Tunnel-like galleries in the inner bark
The ideal treatment window is May-August
Lilac Ash Borer
Affecting many different types of trees, though one of the most common insect issues in Ash trees in particular.
What to look for:
- Large, round exit holes
- Sparse foliage
- Major dieback
The ideal treatment window is May-August
Dutch Elm Disease
Cause by an aggressive fungus spread from tree to tree by female Elm Bark Beetles, this disease ultimately blocks water flow to the crown of the tree resulting in death within a few months to a year.
What to look for:
- Wilting branches
- Leaves that turn yellow, become dry and crumble as they curl
- Dark discoloration or streaks on wood just under the bark
The ideal treatment window is July-September
Spider Mite / Aphid
These are among the most common plant pests. Irrigation and water management are some of the easiest ways to combat them.
What to look for:
- Leaf discoloration
- Leaf loss
- Leaf flecking and scorching
- Honeydew residue on leaves and under trees
The ideal treatment window is July-September
Iron Chlorosis
A lack of chlorophyll due to insufficient iron, this condition is often caused by high-density compacted soil.
What to look for:
- Leaf yellowing on the outsides while veins stay vibrant green
- Overall yellow appearance of leaves
The ideal treatment window is September-October
