American Tree Experts

4 Common Disease-Causing Winter Tree Pests

Here is a complete guide to winter tree pests and how they are harmful to your garden

Winters bring a cessation of activity for many organisms, be it the warm-blooded bears, bats, and chipmunks that hibernate during winters or insects and bugs that become inactive. Many people consider winter to be a safer season because pests are inactive and cannot attack plants. However, that’s not always the case.

During winters, pests take refuge and hide in the tiny cracks and crevasses of the plant. During this time, some pests lay eggs and form multiple colonies inside the tree’s trunks. While these pests remain inactive during the coldest temperatures, with the arrival of spring they become resume activities and multiply in numbers. Late winters and early spring presents a perfect opportunity for some pests to infest your plant.

Let us take a look at some common disease-causing pests that inhibit your trees during winters.

Scale Insects

  • They are small, sap-sucking insects that have a shell-like covering and appearance. They are oval in shape and come in different sizes. Scale insects wrap themselves around the twigs, leaves, branches, and fruit of the tree. They suck sap and other fluids, resulting in a weakened tree. A particularly worrisome aspect of scale insects is that they hide well and cannot be detected easily. At the first glance, the onlooker may mistake them as tiny bumps that are a part of the tree.

Scale insects suck out the tree’s nourishment which causes the foliage to wilt and branches to die.

Hemlock Woolly Adelgid

  • These are tiny sap-sucking insects that most commonly infest and feed on Hemlock trees. They cause widespread death and destruction of hemlock trees in the East part of the United States. Hemlock Woolly Adelgid produces cotton-like wax filaments which are their most distinguishing characteristic.

The damages caused by an infestation of the Hemlock Wooly Adelgid results in the premature dropping of needles, reduced growth, or untimely death of the tree.

Spider Mites

  • winter tree pestsThese insects live on the underside of the leaves and spin silk webs. They feed on the foliage which causes punctures and holes in the leaves. Spider mites have a greenish/yellow appearance and have four pairs of legs. Hence, they get the name due to their resemblance with spiders. They are much smaller in size compared to spiders. The average spider mite is 1/64-inch long. Due to their minute sizes, spider mites are very hard to detect.

However, despite their sizes, they cause considerable damage to common household and indoor plants. The most commonly infest boxwoods, spruces, burning bushes, and junipers plants. Spider mites puncture the leaves with their piercing mouthparts. When feeding on leaves, they leave small discolored dots on the leaves.


  • Bagworms are a type of moth. The adult bagworm may range from 1 to 15 cm in size. Their wings are pale yellow with black stripes. Their name is derived from the bag they build by combining silk and small pieces of the plant’s foliage. The bag allows them to camouflage and become a part of the tree. Female bagworms lay 1,000 eggs in each bag which leads to a rapid infestation of the plants.

The damage caused by bagworm infestation becomes apparent during late summers. By that time, the damage is usually beyond repair.

  • To conclude, plants require protection from pests even during winters. For effective pest control and management, contact American Tree Experts, Inc. We offer pest management services in Mont Clair, New Jersey. Call us at 973-744-6091 to get a free estimate of our services.

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