What Kind of Worms Are Found in Oak Trees?

Orange-Striped Oak Worms

• The orange-striped worms become prevalent in late summer and fall. They are 1-1/2 to 2 inches long and black in color with long, yellow-orange lines along their bodies. They can completely defoliate smaller trees and cause severe damage to whole sections of larger trees, according to University of Georgia agriculturalist Gary R. Peiffer. Generally, these worms only appear once per year and may not need control measures. Bacillus thuringiensis can help to control more severe infestations. Bacillus thuringiensis is a bacteria that occurs naturally in insects and is harmless to plants, animals and humans. It works by paralyzing the digestive system of the insect, which stops feeding and soon dies. Chemical insecticide such as carbaryl can also be used to control orange-striped worms in oak trees.

Carpenterworms

• Carpenterworms can cause leaf browning, leaf dying and worm holes at the tips of branches. These worms are the destructive grub form of a moth. These borers can cause considerable damage and spread from tree to tree. The branches where the worms bore must be cut off. This action is best done by a professional arborist. Trees can then be sprayed with chlorpyrifos or methoxychor, according to North Dakota State University horticulturalist Ron Smith.

Pink-Striped Oak Worms

• Pink-striped worms are another insect that can infest oak trees. These worms are actually the caterpillar form of a moth. The caterpillar is a greenish-brown color with pink stripes along its body. These worms are prodigious eaters and can completely strip a tree of leaves. Repeated defoliation can weaken the health of the tree. Providing additional water and nutrients will help the tree withstand an infestation. Remove the small, yellow-brown bumps under leaves that are the eggs of the worms. For severe infestations, an experienced tree pest control contractor can help you to eradicate this pest from all sections of the tree.

Cankerworms

• Cankerworms, also called inchworms, can defoliate trees very quickly in the spring and fall seasons. They infest many types of trees including oaks, elm, maple, ash, boxelder and hackberry, according to University of Minnesota entomologists Mark E. Ascerno and Jeffrey Hahn. Their populations go through natural cycles of growth and decline that vary in length. Spring worms can be yellow-green to brownish or black. Fall worms may be light green to dark green to black. Though defoliation can be extensive, it generally does not hurt the tree unless the problem goes on for three years or more. Bacillus thuringiensis, a natural bacteria that kills the worms, can help control their number. Chemical pesticides for this problem include carbaryl, malathion, permethrin and cyfluthrin.