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Common Tree Pests of Wisconsin

​Tree Pest Signs & Symptoms

Our Certified Arborists believe that one of the best ways to keep trees healthy and beautiful is sharing our knowledge of common tree pests with our clients. Early and accurate diagnosis of tree care concerns is a great first step to keep damage to your trees to a minimum. By creating our tree pest gallery, our tree care professionals can provide a resource that allows you to begin the plant health care process. While it is still essential to have a Certified Arborist diagnose your unique tree health concerns in person, this tree pest gallery is a great way to identify possible issues affecting your sick or dying tree. Consult the pest gallery below and contact our Certified Arborist today to start a custom plant health care plan for your property

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Tree Pest Control

Emerald Ash Borer

  • Feeds on all true ash trees and causes fatal damage
  • First discovered in Wisconsin in 2008
  • Now confirmed all counties in the southern half of Wisconsin
  • Untreated ash trees will not survive an EAB infestation
  • Treatment consideration should be given to high value, important ash trees
  • Preventive trunk injections performed every other year have been up to 99% effective

EAB Resource Center

Tree Pest Control

Gypsy Moth

  • Feed on the foliage of hundreds of species of plants in North America — most common hosts are oaks and aspen
  • Larvae emerge in late April or early May
  • Trees weakened by heavy defoliation may become susceptible to drought, disease, or other insect attacks
  • Varied control tactics are focused mainly on caterpillar stages

Honey Locust

Honey Locust Leafhopper

  • Small, light green insect that appears in spring and early summer to feed on foliage of Honeylocust trees
  • Shriveled leaves caused by insect sucking plant sap from leaflets
  • High numbers defoliate trees and prevent leaf out
  • Yearly damage contributes to dieback of branch ends and acceleration of deadwood accumulation in the crown
  • Damage may not be fatal but can contribute to major stress in the tree
  • Soil systemic insecticide treatments can keep the pest under control

Japanese Beetle

Japanese Beetle

  • Exotic insect that has a green head and thorax with shiny copper colored wings
  • Has no natural enemies in the United States
  • Both the grub and adult form can cause damage to trees
  • Adult stage causes most visible damage and can cause complete defoliation of a tree when populations are high
  • Favored trees include linden, birches, crabapples, elms, Japanese and Norway maples, mountain ash, and stressed trees of any type
  • Adults feed on the upper surface of the leaf between the leaf veins, leaving behind a skeleton of a leaf
  • Feeding adults release a chemical that attracts other beetles to the target plant

Pine Moth

Zimmerman Pine Moth

  • Affects the health and structure of Austrian, Scots and other pines found in Wisconsin
  • Larvae begin by feeding on bark and if left untreated move into the trunk and branch wood, weakening the wood and compromising the structural integrity of portions of the tree
  • Tunneling in wood creates large globs of sticky resins mixed with sawdust on the trunk and branches
  • Weakened areas often break during wind storms and heavy snow loads
  • Treatments are very time specific and must be properly timed to gain control