What’s Wrong With My Tree? How to Know When a Tree Is Sick

Published on
April 23, 2025

Is one of your trees looking a little under the weather? Like animals, plants can be impacted by many different diseases and health issues. Providing preventative care, knowing the signs of disease and consulting an arborist when needed are all important for maintaining the overall health of your trees. If you find yourself asking, “What’s wrong with my tree," this guide will help take action before it’s too late.

Types of Tree Disease

Caused by microscopic organisms, plant diseases can affect any part of a tree or the whole tree. It only becomes apparent on the tree once the disease takes hold of its host. Tree diseases are often named after the damage that they produce. A few common tree diseases you may see in Tallahassee include:

Leaf Rust

Symptom: Brown and Yellow Splotches on LeavesCause: Leaf rust, also known as rust disease, is a common fungal infection that affects various plants, including trees. It is more common in humid climates, as wet conditions increase the growth and release of spores. While it rarely kills plants, it can make them appear unsightly and it cripples the plant by interfering with photosynthesis. Treatment: In many cases, an infected tree will naturally fix this issue by shedding its leaves in autumn (although spores can be dispersed by the wind to infect new trees). The best treatment is prevention. You can plant trees in areas with good air circulation and rake and dispose of infected leaves. In severe cases, fungicides may be used to manage leaf rust.

Fire Blight

Symptom: Twigs Appear ScorchedCause: Fire blight, a bacterial infection, changes the appearance of trees to seem as if they were scorched by fire. Leaves on some branches wither and turn black or brown. The bacteria causing fire blight is particularly active in warm, moist weather. Elements such as rain and infected pruning tools provide transportation for the disease to move. Treatment: The best way you can treat trees from fire blight is to disinfect pruning tools, and then prune infected spots on the trees.

Powdery Mildew

Symptom: White Coating on LeavesCause: Powdery mildew is a white coating that forms on leaf surfaces during weather with high humidity. Several fungi can cause this disease, with plants that grow in shaded areas being most affected. Leaves are covered with a thin layer or irregular patches of a powdery, grayish-white substance. Leaves may become distorted and night also turn yellow or red and drop. In late fall, tiny black dots may be scattered over the white patches like grains of pepper.  Treatment: While it's often more of a cosmetic issue than a serious threat to the overall health of established trees, it can weaken young or stressed trees. You can prune and remove severely infected leaves or branches to reduce the overall fungal load and prevent further spread.

What’s Wrong With My Tree? Other Signs of a Sick Tree

Here are a few more common signs that a tree may be experiencing health issues: Visible Pests: The presence of pests like caterpillars, borers or scale insects can weaken a tree and lead to health issues. Exposed Roots: If tree roots are exposed or damaged, it can impact the tree's stability and nutrient absorption. Root Rot: Signs of root rot include a foul odor, discolored or mushy roots and instability. Twisted or Distorted Growth: Unusual growth patterns, such as twisting or distortion, may be a response to stress, diseases or insect damage. Visible Decay: External signs of decay, such as soft or crumbly wood, may indicate internal decay. Premature Leaf Drop: If a tree drops its leaves before the typical fall season, it might be stressed due to factors such as drought, diseases or root issues. If you notice any of these signs, it may be time to consult with a certified arborist or tree care professional.

Frequently Asked Questions Beyond “What's Wrong With My Tree?”

What causes trees to get sick? Trees can get sick due to various factors, including fungal infections, bacterial diseases, pest infestations, poor soil conditions, root damage, environmental stress and physical injuries. Is leaf drop always a sign of a sick tree? Not always. While leaf drop can be a sign of stress or disease, it can also be a normal seasonal process. Can environmental factors make a tree sick? Yes. Factors like drought, excessive moisture, poor soil quality and pollution can stress trees and make them more susceptible to diseases and pests. Can I treat a sick tree myself, or do I need professional help? While minor issues can be addressed by homeowners, it's often advisable to consult with a certified arborist for accurate diagnosis and treatment recommendations, especially for significant tree health concerns.

Consulting the Experts

Not all diseases will kill plants and trees. However, many diseases and conditions can hinder growth and affect the look of the trees. If you have concerns about a sick tree, especially trees affected by diseases that may inflict property damage, call Miller’s Tree Service for a free consultation with one of our certified arborists. Our team will assess the tree's health, identify the underlying issues and recommend appropriate treatments or interventions to improve its condition.

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