5 Insects & Fungi To Look Out For This Fall

Monday marks the first day of fall. With fall comes a new assortment of insects, fungi, and diseases that will feed on and hurt your plants. Learn what pests pose a danger to your trees and shrubs and what signs you should keep an eye out for on your property this fall.

1. Fall Webworms

Fall Webworms 2

Fall Webworms are a native pest of shade trees and shrubs that emerge throughout mid-late summer and fall. These caterpillars weave webs in trees & shrubs while feeding on the plants leaves. If left untreated, these insects will defoliate numerous branches and possibly the entire tree. Between the defoliation and giant webs, this pest turns trees into an eyesore.

Species Targeted: Fall webworms target almost all shade, fruit, and ornamental trees except conifers. In the United States, about 90 species of trees are regularly affected. The most susceptible in our area include hickory, walnut, elm, birch, cherry, redbud, willow, oak, mulberry, crabapple and some maples.

Learn More About Fall Webworms

2. Spruce Spider Mites

spruce spider mites

The spruce spider mite (Olibonhychus ununguis) is a cool-season mite native to North America. This insect is one of the most destructive kinds of spider mites. These mites thrive during the spring and fall causing stippling on needles, yellow or rust-colored needles, premature needle drop, and fine webbing in needles. 

Species Targeted: Spruce spider mites prefer Colorado blue spruce, Norway spruce, dwarf alberta, and white spruce. However, they will also feed on arborvitae, cedar, dawn redwood, Douglas fir, hemlock, juniper, larch, and pine. 

3. Fall Cankerworms

Fall cankerworms are leaf-chewing caterpillars that attack a variety of hardwoods.  They cause small holes on leaves, defoliation of leaves with veins still intact, limb dieback, and loss of vigor. Mature, healthy trees may be able to withstand a few years of infestation; however, if you have young, weak, transplanted, or new trees, one infestation of cankerworms can severely damage your tree.

Susceptible Trees: Fall cankerworms have a wide host range, but prefer elm, apple, dogwood, cherry, a variety of oaks including Willow oak, linden, ash, hickory, hackberry, maple, and beech.

4. Armillaria Root Rot

Tree Fungus - Armillaria Root Rot

Also known as Oak root fungus, Armillaria root rot is a disease caused by the fungi of the genus Armillaria. It causes dulling of leaf color, loss of vigor, leaves turning yellow or brown, and leaves wilting. If left untreated it will cause rapid decline and death. In the worst cases, when left untreated trees can become structurally unsafe and uproot or snap possibly causing property damage and injury. 

Species Targeted: This tree fungus has an extremely wide range of hosts. Most trees and shrubs are susceptible to Armillaria root rot; however, it’s very commonly found on Oak trees. 

5. Bagworms

Bagworms, found throughout the Eastern United States, are a major pest for evergreens. These insects are known for the cone-shaped bag they create around themselves, hence their name. These insects damage trees by feeding on their foliage. Most trees will see partial defoliation; however, some heavily infested trees will experience complete defoliation. The greater the amount of defoliation the greater amount of stress is put on the tree which can lead to other health issues like insects and fungi that prey on weakened trees.

Species Targeted: Arborvitae and Red Cedar are the tree’s most favorite host but Cypress, Juniper, Pine Spruce, Apple, Birch, Black Locust, Elm, Maple, Poplar, Oak, Sycamore, Willow and over 100 other species are also attacked by the pest.

Learn More About Bagworms

If you see signs of these insects or fungi it’s best to act fast. Give us a call at 703-573-3029 to schedule a consultation or book a consult online using our online booking system

2 thoughts on “5 Insects & Fungi To Look Out For This Fall”

  1. Beverly Anderson says:

    As usual, your wonderfl articles are timely and informative. I’m a bit confused about ARMILLARIA ROOT ROT. Your article included a photo of what I call mushrooms. Does the presence of these mushrooms indicate Armillaria Root Rot? Could the mushrooms in your photo be the result of something else?

    1. Rtectree says:

      Hi Beverly,

      Thank you for your kind words. I’m glad you enjoy our articles. To answer your question, all mushrooms are fungi, but not all fungi are mushrooms. Mushrooms are similar to fruits or flowers that plants produce. Like an apple is a fruit of an apple tree, a mushroom can be a product of certain types of fungi. Some mushrooms/fungi are harmless; however, if you have mushrooms growing around the base of your tree it could be cause for concern. It could be Armillaria Root Rot or even another type of fungi that’s dangerous to your tree. I’d suggest having one of our Certified Arborists take a look at the tree. You can schedule a consultation by calling 703-573-3029 or even send some pictures along with a description to admin@RTECtreecare.com

      Thank you for your question!
      -Samantha H.

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