Evergreen Tree Farm

The Most Common Tree Diseases and Infestations in Wisconsin

A couple months ago I was assisting a client on the rebuilding of their landscape. They owned a nice, quaint home in the suburbs near Oconomowoc with a beautiful sycamore on the front lawn. On my first visit I noticed that the tree had been overrun with anthracnose fungal growths. If this had been found early, we would have been able to prune and trim away the infected areas. Unfortunately, that wasn’t the case. The entire tree needed to be removed to preserve the rest of the foliage and natural landscape. While I have a tree removal team that I know and trust, tree removal should always be the last option. That’s why in this article we’re going to go over the signs that your tree may be infected with a disease or infestation. By addressing the problem early, you stand the greatest chance of protecting and saving your trees.

Anthracnose : To begin with, let’s break down Anthracnose since it’s fairly common. Especially during the fall and winter seasons. Anthracnose is a fungal infection that creates ulcer-like sores on the leaves and branches. Because Anthracnose is a family of fungal infections, it will affect different tree species differently. However, the general look and texture of the fungal infection, remains consistent. The cause of Anthracnose is most often a buildup of water. The fungal cannot survive if water is not present. So, one great way to prevent this disease is by avoiding spraying the leaves and branches of your tree excessively. Keeping the water accumulation to the root system will prevent fungal buildup and make sure that the soil remains nutrient dense.

Downy Spot (White Mold) : This very common fungal infection is most easily recognized by yellow spots found near the veins of leaves. Near spring time, those spots will turn white and powdery on the underside of the leaf. After some time, those powdery sections will grow lesions as the leaf turns brown and shrivels up. The easiest way to aid an infected tree is by treating the infected areas with fungicide and pruning where necessary.

Emerald Ash Borer : The Emerald Ash Borer is a stunningly beautiful species of beetle that simply does too much damage to trees. They will burrow their way into a tree and then plant their eggs. The issue arises when the eggs hatch and larvae burrow themselves further into the tree. Making their way between the bark and main portion of the trunk. This is an important part of the tree for water transportation and nutrient storage. If the beetles are left untreated, they will damage those reserves, causing the tree to be unable to transport those nutrients to the top. Leading eventually to the death of the tree. A massive problem caused by a very small bug. The easiest way to detect these pests is by looking for holes within your leaves or emerald colored beetles hanging around your tree.

Gypsy Moth : These destructive creatures are originally native to Europe and North Africa. However, they made their way to Wisconsin in the 1980s. Now, nearly every decade the species has a massive population explosion, leading to the harm and death of many trees. While these moths often target only a select type of tree, they can break away from their normal pattern and leave behind large-scale havoc. Because of these insects, the eastern half of Wisconsin is often considered a quarantine area so that authorities can limit the infection of trees throughout the rest of the state and surrounding areas. Gypsy Moths can be eliminated early on by the use of certain pesticides. If left untreated, the caterpillars are able to inflict significant damage and can even lead to death. To know whether your tree has contracted Gypsy Moths, be on the lookout for red and black caterpillars along leaves with orange spikes protruding from the sides.

Trees will most often outlive our lifetimes. As we either inherit or plant them, it is our responsibility to keep them healthy. Many of the diseases and infections on this list are preventable through vigilance. If you notice changes in the trees leaves or branches, it’s best to schedule an expert consult sooner rather than later. Due to Wisconsin’s strong seasons and long wet periods, the opportunities for infection are larger than desert or mountainous regions. However, addressing any problems early on is very manageable. So, keep enjoying all the benefits your tree has to offer and give it a look over every two or three months. That way, you and your tree stay healthy.