Tag Archives: Anthracnose

Symptoms of Anthracnose

Dark brown irregular blotches on foliage indicates an anthracnose infection

Prevent anthracnose from harming your trees, shrubs, and turf, causing their decline and eventual death. By knowing how to identify this pesky fungal disease, you can take steps to control and prevent it.

72tree.com gathered information to help you identify the symptoms of anthracnose, what it infects, how to treat it, and how to prevent the disease.

What Is Anthracnose

Anthracnose is the name given to a group of fungal pathogens that attack a wide variety of herbaceous and woody plants in spring with cool and wet weather. Fungi overwinter (lie dormant) in dead twigs and fallen leaves. Cool, rainy weather provides perfect conditions for emerging spores to spread.

Anthracnose Symptoms

Anthracnose symptoms can appear differently depending on what part of a plant or tree it has infected. The following will help you positively identify an anthracnose infection:

Twig, Branch, and Stem/Trunk Symptoms – Anthracnose infections on twigs most commonly appear as small orange-brown blisters or as a brown band encircling and girdling the young twig resulting in shoot death.

In more advanced cases, anthracnose can cause open wounds on branches, stems, and trunks. These open wounds typically appear sunken, dark, and wet.

Anthracnose causes discoloration and death of twigs and branches

Leaf Symptoms – Tan to dark brown irregular shaped blotches develop on young leaves, and they are typically distorted, cupped, or curled. When there is a severe anthracnose infection, premature leaf drop can occur in spring. When this happens, trees will usually produce a second growth of foliage by midsummer.

An anthracnose infection may cause identical spots on mature leaves. Still, these leaves generally do not portray the cupped or distorted appearance. These spots on mature leaves are frequently accompanied by minor wounds from insect feeding.

For trees, these symptoms are typically most severe on lower and inner branches but can travel up through the entire canopy.

Fruit Symptoms – Anthracnose fruit rot is identified as brown to black, water-soaked, sunken spots on green and ripe fruit. These lesions can develop over time, depending on weather conditions during disease development.

Grass/Turf Symptoms
– Anthracnose diseases are common and destructive problems in landscapes and golf course greens with creeping bentgrass or annual bluegrass.

Anthracnose may develop in grasses as a foliar blight, in which grass leaves are infected, or a basal rot, attacking leaf sheaths, crowns, and stolons.

Anthracnose symptoms in grass and turf can be highly variable. Consider the following:

•Yellow to orange spots in irregular patterns
•Small freckle-like spots
•Circular patches reaching a foot in diameter

Symptoms are typically most severe in areas that are stressed from low mowing, excessive traffic, or inadequate irrigation or fertilization.

These symptoms first appear on the oldest growth, which dies back from the tip. The disease then gradually progresses to the younger leaves.

As the disease progresses from the foliage to basal rot, the leaf sheaths, crowns, and stolons will be darkened and rotten.

Tip: Use a magnifying glass to identify acervuli. These black, saucer-shaped pads with protruding black spines (setae) are the disease’s reproductive structures filled with spores.

Anthracnose Disease Cycle

An anthracnose disease cycle starts when a host is infected in spring or early summer from spores in fallen leaves, infected twigs/limbs, and lesions called cankers. Leaf infections commonly progress to stem and bud infections where the pathogen continues to grow and cause dieback.

Dieback is frequently the result of cankers growing over multiple years and, unless treated, will result in hydraulic failure to foliage, the decline in health, and vulnerability to deadly pathogens and/or infestations.

Dieback and defoliation caused by anthracnose

Generally, anthracnose infections are not lethal to plants and trees. But, if the pathogen is left to flourish for multiple growing seasons, it will weaken its host, allowing other diseases or insects to successfully attack and kill it.

Anthracnose Treatment

Due to the ease in which anthracnose spreads and infects plant life, once identified, fast action is required to prevent a wide-spread, severe outbreak. The following will help you reduce transmission of the pathogen:

•Apply a broad-spectrum, non-toxic bio-fungicide safe for organic use directly on and around infected areas
•Halt all overhead watering practices and install drip lines where possible
•Carefully prune and destroy all infected foliage, stems, and branches
•Collect and destroy fallen leaves, twigs, and debris from beneath infected trees, shrubs, and plants throughout the growing season and summer months
•Sanitize all pruning and gardening equipment after each use with a one part bleach to 4 parts water solution
•Call a professional tree service to treat cankers on tree trunks (tree removal may be required in more severe stages of infection)
•Do not walk through or work on your garden, lawn, or shrubs when they are wet
•Avoid composting infected foliage, fruit, cuttings, or stems
•Thoroughly clear debris from gardens and from under shrubs and trees in the fall to reduce overwintering opportunities for fungal spores

Read more about treating and eliminating fungi at 72tree.com/how-to-get-rid-of-tree-fungi/

Anthracnose Prevention

While it can be challenging to prevent, the following measures will help you protect your garden, bushes, and trees from anthracnose:

•Use western grown seeds which have not been exposed to anthracnose
•Plant disease-resistant species when possible
•Water, fertilize, prune, and mulch your plants and trees to promote their health
•Apply liquid copper sprays weekly throughout the growing season
•Apply sulfur powders weekly throughout the growing season
•Apply neem oil at the first sign of budding, then weekly throughout the growing season

Note: Neem oil is an organic, multi-purpose fungicide, insecticide, and miticide eliminating all stages of insects while preventing fungal attacks.

Anthracnose prevention with all natural neem oil

Anthracnose Symptoms, Treatment, and Prevention

In this article, you discovered what anthracnose is, how to identify it, and measures to treat and prevent it from harming your landscape.

By taking swift action to halt the progression and prevent anthracnose infections, you are preserving the health of your grass, plants, shrubs, and trees.

Allowing anthracnose to spread without treatment will leave the plant life on your landscape in poor health and susceptible to more deadly pathogens and infestations.



Common Maple Tree Diseases, Symptoms, Treatment, and Prevention

Red maple tree acer rubrum health and diseases

Stop your maple tree from needlessly dying. If caught in time, diseases that attack maples can be treated with success.

72tree.com of Alpharetta Ga, assembled the following list of diseases that affect maple trees, how to identify, treat, and prevent them.

Why do My Maple Tree Leaves Have Spots?

One of the easiest ways to detect maple tree diseases is through irregularities in shape or size, spots, and/or blemishes on the tree’s foliage.

The following diseases may cause spots to appear on your maple tree’s foliage:

Leaf Spot (Phyllosticta minima) – This fungal infection causes round spots about a quarter of an inch in diameter to appear on leaves. These spots will have a pronounced purple border and blackish dots in the center of the spot (fungal fruiting structures).

Treatment: Before fall, prune dead twigs, stems, and branches. Collect all clippings and destroy them (burning them is highly recommended) to prevent the spread of the fungus.

Have the tree evaluated to determine the extent of the infection and whether further action like using fungicides should be taken to protect your tree and surrounding landscape.

Maple tree infected with leaf spot phyllosticta minima disease

NOTE: Sanitize all equipment, including gloves and protective clothing that come in contact with an infected tree and its foliage.

Anthracnose (Aureobasidium apocryptum or Discula – Gloeosporium) – Anthracnose is a fungal infection that causes purple or brown streaks to occur alongside and between leaf veins. In some maple species, drought and heat stress can produce similar symptoms. You can confirm an anthracnose infection by locating small, brown fungal fruiting structures near the veins of affected leaves.

Treatment: The same measures and precautions for leaf spot should be used in the treatment of anthracnose.

NOTE: Anthracnose can lead to severe defoliation during a wet spring season.

Root Rot (Fomes fomentarius, Ganoderma lucidum, or Laetiporus sulfureus) – Once a fungal infection embeds itself in the trunk or the roots of a maple tree, there are three types of symptoms to watch for:

• Foliage in the entire crown or a section of it may suffer from chlorosis, wilt, die and eventually fall. This happens as the fungi cause hydraulic failure within the roots, trunk, and branches.

• Fungal fruiting structures (mushroom conks) will appear from late spring to mid-fall. For these structures to form, there must be rotting organic material within the tree.

Maple tree root rot with mushroom conks diseased and dying

• Large black ants known as carpenter ants will make a nest for their colony within trees that suffer from heart rot. These ants do not burrow through heartwood, they remove the tissues rotting and softened from the infection.

Treatment: Once root rot or heart rot has been confirmed, have the tree professionally removed as quickly as possible.

NOTE: The presence of carpenter ants and fungal fruiting structures only occur after significant damage has been done to the tree. When the affected tree is within striking distance of your home, places where people congregate, or other structures and vehicles, the situation should be treated as an emergency.

Galls – These spots are irregular growths or swellings that occur from a reaction to tissue feeding or egg-laying by various species of mites and insects (commonly mistaken for fungal infection).

Maple tree disease galls formed on the top side of a leaf

Galls appear in various ways. Each mite or insect species produces a distinctive gall shape and can range from wart-like bumps to felt-like patches to spindle-shaped protrusions. Galls develop in the spring, and once formed, the pest remains protected within the structure. Arborists can often identify which mite or insect has infested your tree by the shape and appearance of the galls.

Treatment: Leaf galls are relatively innocuous and rarely result in any long term damage to the tree. Applications of pesticides are relatively ineffective, as the pests are protected within the gall structure.

The most effective manner of gall removal is to handpick and destroy affected foliage before exit holes form and allow the pest(s) to move on. If the presence of galls is overwhelming, hire a professional tree service to evaluate the situation and recommend a course of action.

Maple Tree Disease Prevention

Maple tree disease prevention begins with good tree care practices. The healthier your tree is, the more vigorously it can fight back against diseases and infestations.

However, when the tree’s defenses fail, here are steps to prevent the disease or infestation from infecting surrounding trees:

• Prune affected limbs (before leaf-drop)
• Burn all pruned limbs and foliage
• Always sanitize pruning equipment after use on an infected tree
• Avoid tracking soil from around infected trees to areas around uninfected trees (many fungi and other pathogens thrive in the soil). Clean boots, protective clothing, tools, and equipment before leaving an infested area
• Replant resistant species after tree removal
• Avoid planting maple trees in areas with a history of tree diseases
• Have annual tree inspections and soil testing performed to detect any issues early on.

Black Spots on Maple Leaves

In this article, you discovered how to identify diseases that cause spots on maple tree leaves, how to treat them, and how to prevent them.

Prevent the decline of your maple tree by knowing what to do when a fungus or pathogen begins showing signs of infection.

Your choice to ignore signs that your tree is diseased or in decline can result in catastrophic fungal outbreaks to your landscape, or costly damages to your property when the tree falls.