If you have trees in your yard, there is a possibility your trees might be infected by tree fungi. Despite caring for it, it is a normal part of owning a tree.
Not all tree fungus is fatal. Sometimes, they only ruin the tree's beauty. Here is everything you need to know about identifying tree fungus, the damage it causes, and treatment options.
1. Different Parts Of Tree
Fungi grow and feed on specific parts of the trees. Therefore inspecting these parts will help identify if your tree is infected with fungus. Here are some things you should know.
Target Zones
Different fungi target different parts of the tree. For example, some attack dead wood on branches or fallen logs, while others target living tissues like the trunk or roots.
Living Tissue: Fungi that grow on live trees are harmful to the tree. These fungi might be found on the trunk or branches, causing cankers, decay pockets, or other damage.
Dead Tissue: Meanwhile, fungi found on fallen branches, stumps, or the undersides of dead branches break down dead organic matter without harming the living tree.
Roots: Root rot fungi typically live hidden beneath the soil, but their presence might be signaled by wilted leaves or stunted growth in the tree.
Moisture and Nutrient Availability
Different fungi have different moisture and nutrient needs. Location can provide clues about these factors.
High Moisture Areas: Fungi that thrive in moist environments might be found on the underside of branches, near wounds on the trunk, or at the tree base, where water accumulates.
Direct Sunlight and Shade: Some fungi prefer sunnier locations on the tree, while others favor shaded areas.
Entry Points: Sometimes fungi enter trees through wounds, weak spots, or natural openings.
Wood decay in a tree is a clear indication of fungal infection, often characterized by soft, spongy, or crumbly wood that may easily break apart. This decay is caused by fungi that invade and decompose the structural components of the tree, such as cellulose and lignin, leading to a weakened and compromised tree structure.
Visible signs of wood decay include conks or mushrooms growing on the trunk or branches, discoloration of the wood, and the formation of cavities or hollow sections within the tree.
3. White Fungus
White fungus on tree is another sign of infection. It is caused by powdery mildew or other similar fungi. It appears as a white, powdery substance on leaves, stems, and sometimes on the bark, forming a visible coating that spreads rapidly.
The white fungus is more pronounced in areas with high humidity and poor air circulation. It not only affects the aesthetics of the tree but also disrupts photosynthesis by blocking sunlight from reaching the leaves. If untreated, the tree are more susceptible to diseases and environmental stressors.
4. Lichen
If you spot lichen on trees, do not confuse it as a sign of fungal infestation. Lichen are symbiotic organisms and not a fungus. It does not harm the tree, but its presence is a sign that the tree has health issues. Lichens thrive in environments with poor air quality or where trees are stressed or weakened.
If you notice an abundance of lichen on a tree, it may be a sign the tree is struggling and could be more susceptible to fungal infections or other issues. It is better to examine the tree to confirm if it is infested with fungus.
Greenish powder or fuzzy growth on surfaces is a sign of green fungus on trees. These fungi appear green in color, often due to the presence of green pigments or spores. The presence of green fungus is a sign of fungal infestation. It may indicate underlying issues such as decay or disease.
These fungi often thrive in moist, decaying organic matter and can weaken the tree by infecting its bark, branches, or leaves. It is crucial to examine the situation more closely if you notice green fungus on a tree to assess the severity of the infestation and take the necessary steps to address it.
6. Mold
Another sign of fungal infestation is mold on tree surfaces. Mold appears as a fuzzy or powdery layer on leaves, branches, or bark and usually grows in damp, shady areas. It ruins the beauty of the tree and disrupts photosynthesis, causing leaves to fall off early.
Mold is caused by different fungi, like powdery mildew or downy mildew. It occurs when a tree is growing with poor airflow or too much moisture. If you see mold, talk to an expert to identify the fungus and how to treat it.
Leave damage is a common sign of fungus infection. If a tree is infected with fungus, the leaves have spots, blotches, or lesions in various colors, like brown, black, yellow, or white. Infected leaves may develop a powdery or fuzzy coating and leaf edges or entire leaves may curl, wilt, or show signs of distortion.
Additionally, fungal infections can cause the leaf surface to become covered in tiny, raised pustules or bumps, often orange or red, which are fungus spores. These symptoms interfere with the leaves’ ability to photosynthesize effectively, reducing growth and vitality.
8. Cankers On Barks
Cankers are sunken, dead areas on the bark that ooze sap and can vary in size and shape. They are a strong indication of a fungal infection. Fungal pathogens enter the tree through wounds or natural openings, causing localized infections that lead to canker formation.
Cankers damage the tree’s vascular system, inhibiting the flow of water and nutrients and weakening the tree structurally. Weak trees are more susceptible to further infections and infestations. The presence of cankers can also be associated with leaf symptoms mentioned above.
Cracks and splits on the bark and trunk of a tree are another indication of fungal infection. They appear as long, vertical fissures that run up and down the trunk. They are deep enough to expose the inner wood.
The wood inside the crack may show dark streaks or staining. The bark around the cracks may appear sunken or depressed, indicating dead tissue. Fungal pathogens invade the tree through these openings, leading to further damage and creating an entry point for additional diseases and pests.
10. Dieback
Dieback is a condition where the tips of the shoots, branches, or leaves begin to die back toward the main stem or trunk. It is a sign of fungal infection caused by pathogens such as Botrytis, Phytophthora, and Verticillium.
These pathogens invade the plant's vascular system, disrupting the flow of water and nutrients, leading to the decline and eventual death of the affected parts. This condition often starts with the leaves wilting, turning brown, and eventually falling off, leaving behind bare branches. If left untreated, it can lead to the loss of the entire tree.
11. Witches Broom
Witches broom is a growth abnormality in trees and shrubs caused by fungi, like Taphrina or rust fungi. It is characterized by a tight cluster of shoots or branches growing haphazardly. These disorganized clusters of shoots have a broom-like appearance. They can appear on various parts of the tree, including branches, stems, or trunks.
This haphazard growth is unsightly and can affect the aesthetics of the tree. It can also weaken the branches and increase breakage risk. Witch broom can significantly reduce fruit production for fruit-bearing trees as the tree’s energy is diverted from fruiting.
12. Root Rot
Root rot is another sign of fungal infection in trees. This condition occurs when fungi attack the tree’s root system, causing the roots to become soft, black, and mushy. Root rot occurs in environments with poor drainage or excessive moisture.
Symptoms include stunted growth, yellowing or wilting leaves, and an overall decline in the tree's vitality. As the roots deteriorate, the tree cannot absorb water and nutrients properly, leading to a weakened structure and increased susceptibility to other diseases and pests.
13. Fruiting Bodies
Fruiting bodies are the structures produced by fungi to produce and release spores, which are the fungal equivalent of seeds. They come in various forms, like mushrooms, conks, sclerotia, pustules, or spores, and are found on the surface of the bark or near the tree base.
They develop when the fungus has reached a certain stage in its life cycle and is producing spores to spread to other areas. These fungal seeds suggest that internal damage may be occurring. It is a sign that the tree is suffering from a deadly fungal disease, which can weaken the tree’s structure and health.
14. Discolored Wood
Discolored wood usually occurs beneath the bark and indicates fungal infection in trees. The color appears dark, streaked, or abnormal, which is a sign that fungi are affecting the internal tissues. This color is different from healthy disease-free wood, which can range from light tan to deep brown, depending on the type of wood.
If the fungus is not dealt with, it can spread to nearby trees or plants through spores, potentially leading to a broader outbreak of infection within the area. This can affect the health of nearby plants and trees.
When a tree is infected with fungi, it often struggles to absorb the nutrients and water it needs to thrive. This disruption can lead to smaller leaves, stunted branches, and slower growth. Affected trees may also exhibit less vigorous foliage and a decline in their usual growth rate.
Reduced growth affects the plant’s overall health and resilience. It is vulnerable to pests, diseases, and environmental stress. It can affect the plant’s ability to photosynthesize effectively. For ornamental plants, slower growth can reduce overall visual appeal.
Treating Tree Fungus
If you notice any of the signs mentioned above and suspect your tree is infected with fungus, it is important to address any issues promptly to help restore the tree’s health and vitality. Treating tree fungus involves a combination of different methods. Here are steps to effectively manage and treat fungal infections in trees:
Diagnose the Fungal Type
Different fungi require different treatments, so accurately identifying the fungus should be the first step. To diagnose the fungal type infecting a tree, observe symptoms like spots, mold, or cankers.
Compare these with known fungal diseases using field guides or online resources. Consult an arborist for accurate identification, as a precise diagnosis is crucial for effective treatment and preventing further spread.
Treating fungus requires improving air circulation. You should prune overcrowded branches to allow better airflow through the canopy. Remove any nearby vegetation that restricts airflow.
Space trees adequately when planting and keep the area around the tree base clear of debris to reduce humidity and prevent fungal growth.
Sanitation
Sanitation is crucial for treating tree fungus effectively. Regularly remove and destroy infected leaves, branches, and other debris to prevent the spread of fungal spores. Clean up fallen leaves and fruit around the tree base.
Sterilize pruning tools with bleach or rubbing alcohol between each cut to avoid transferring pathogens. Avoid leaving pruned materials near healthy trees. Dispose of infected plant material by burning or discarding it, never composting.
Fungicides
Fungicides target and inhibit the growth of fungal pathogens. They can be applied as sprays, drenches, or injections, depending on the type and severity of the infection. To use fungicides, first, identify the specific fungus affecting the tree and select an appropriate product.
Follow the manufacturer’s instructions for mixing and application rates. Apply the fungicide evenly to affected areas, ensuring thorough coverage. Repeat applications as recommended, especially during wet seasons.
Preventive Sprays
Preventative sprays create a protective barrier that inhibits fungal spores from germinating and spreading. These sprays are most effective when applied during vulnerable periods in the spring and fall.
Identify the appropriate fungicide for your tree and fungal issue. Follow the manufacturer’s instructions carefully, mixing the fungicide with water if required. Apply evenly and thoroughly to all surfaces of the tree.
Pruning helps remove infected branches, improve air circulation, and reduce humidity, which inhibits fungal growth. Use sterilized tools to cut off infected parts. Dispose of pruned material to prevent spreading spores.
Prune during dry weather to minimize the risk of spreading fungal spores and avoid excessive pruning, which can stress the tree.
Bark Treatments
Bark treatments involve removing diseased bark. This process eliminates the infected tissue, preventing the fungus from spreading further. Use a sterilized knife or chisel to carefully cut away the infected bark, ensuring you reach healthy wood.
Discard the removed bark and sterilize tools between cuts. After removal, apply a fungicide to the exposed area to kill any remaining spores.
Mulching
Mulching improves soil health and reduces moisture around the base, which limits fungal growth. Apply mulch in a 2-4 inch layer around the tree’s base, extending to the drip line but keeping it away from direct contact with the trunk to prevent rot and further fungal issues.
Use organic materials like wood chips or bark, which decompose slowly and enhance soil structure.
Arborist Consultation
If the infection is severe or widespread, consult a certified arborist. They are trained to accurately diagnose the fungus affecting your tree and recommend appropriate treatment options.
They can also suggest preventive measures to avoid future infections.
