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Tree Problems

Boring Insects

Pine Beetle
Attacks most pine species in the Front Range area. Trees that are not growing with vigor as a result of being over-topped, over crowded, old age, or stressed due to drought or damage are the most susceptible to attack. Proactive treatments are recommended.

Ash/Lilac Borer
Attacks mostly Green Ash and Lilacs. This borer is most likely to attack stressed or damaged trees, but can attack an apparently healthy tree. These borers can cause extensive damage to Ash trees, causing  the main leader of the tree to die off to killing the entire tree. Proactive treatments are recommended.

Locust Borer
Affects mainly Locust trees. This borer is most likely to attack stressed or damaged trees, but can attack an apparently healthy tree. These borers can cause extensive damage to the Locust tree, boring large galleries throughout the trunk, severely damaging the vascular system and further weakening the tree. Proactive treatments are recommended.

Ips Beetle
Infests Spruce, and Pine species. There are 11 species of Ips that are found in the state of Colorado. These beetles mainly attack weak, stressed, or damaged trees as a result of transplanting, drought, or poor site conditions. Ips beetles are also known as “engraver” beetles. Preventative or proactive treatments are recommended.

Protection from fungal and bacterial diseases

Leaf Spot Fungus

A fungus that commonly affects Aspens. It commonly shows up in late summer or early fall after a warm, wet spring, which provides the ideal conditions for the fungus to grow and spread. It is not usually recommended to treat with fungicides if the fungal infestation is not a chronic problem, which shows up year after year. This is due to the fact that Aspens are sensitive to certain types of pesticides.

Fire Blight
A bacterial disease that infects most flowering trees, such as apple, crabapple, and pear. This disease will kill off branches and, if the infection in severe enough, the entire tree. This disease is spread by pollinating insects, water, and pruning tools contaminated with the bacteria. Pruning out the infected areas, sanitizing your cutting shears in a 10% bleach solution between cuts and preventative treatments are affective in managing Fire Blight.

Powdery Mildew
A widespread disease that is easily identified. It appears on the foliage of infested trees as a white dusty, or powdery film. The warm and dry climate of the Front Range of Colorado is an ideal climate for severe outbreaks to occur. Infections are likely to occur in tightly planted areas where circulation is limited.

Protection and treatment for foliar pests

A foliar pest that feeds on the nutrients that the foliage is producing for the tree. Aphids can be found on many species of trees, and some species can cause damage. They can be controlled by the use of pesticides as well as the use of predatory bugs such as ladybugs and parasitic wasps.

Spider Mites
Are a common foliar pest that causes leaf discoloration and burning, leaf loss, and often kill trees or brutally stress them. In Colorado, spider mites tend to show up most heavily in the late summer/early fall after the plants have been stressed all summer from drought and heat. Spider mites can be controlled by miticides, or with predatory mites, lady bugs, and parasitic wasps.

There are four types of webworms in Colorado. Tent caterpillars are common in the spring, causing foliar damage. The most damage occurs in already stressed trees. The fall webworm occurs from midsummer through early fall. Mostly they are an eyesore and for aesthetic reasons, are wanted to be removed.  

Tussock Moth
Attacks Douglas-firs, spruces, and true firs and feeds on the needles. From time to time, infestations occur through out the urban forest of the Front Range. Rarely does it occur as a true forest pest in the Colorado forests. There are several pesticides that are affective for controlling the Tussock Moth.

Tip Moth
The tip moth causes damage in its caterpillar stage of its lifecycle. It feeds on the new foliage of many different pines. Rarely causes severe damage, but affects the appearance and growth. The tip moth can overwinter in the terminal growth of Pinion pines. There are several pesticides that give good control of this tree pest.

Zimmerman Pine Moth
Larvae cause damage by tunneling under the bark, usually where a branch meets the trunk, to feed on the cambium layer of the tree. Like the Pine beetle, yellow “popcorn is a tell-tale sign of their presence. Proactively treating your trees with preventative sprays is the most effective way of protecting your trees.

Affects several species of trees here in Colorado from evergreens to Aspens. Scale feeds on the nutrients that the host tree is producing for itself. Control of certain types of scale can be difficult due to a hard protective coating that the insect covers itself with. The “crawler” stage is the most effective time to treat these types of scale.

Nutrient Deficiencies

Iron Chlorosis
Chlorosis is a term that describes a yellowing of the leaves. Chlorosis is a symptom that a tree is nutrient deficient. In the Front Range of Colorado, the soil pH is such that the iron in the soil becomes bound to the soil, not allowing it to be absorbed by the roots of the trees. The result is a chlorotic tree that will eventually die due to malnutrition if nothing is done.  




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