Fungal Diseases of Plants

Anthracnose is a fungal disease that can affect leaves, flowers, fruit, and stem tissues. It's caused by fungi that produce conidia in structures called acervuli. The fungi that cause anthracnose are usually Colletotrichum or Gloeosporium.

Anthracnose can cause: 

Leaf spots

Cupping or curling of leaves

Early leaf drop

Wilting, withering, and dying of tissues

Drying out of leaves and young fruits

Mature fruits drying out and remaining hanging

Anthracnose survives on infected plant debris & spreads easy.

It appears as white, powdery spots on the leaves, stems, buds, young shoots, fruits, and flowers. The spots can also be grayish and talcum-powderlike. 

Leaves: Leaves may turn yellow, die, and fall off.

Fruit: Fruit may be exposed to sunburn.

Leaves: Leaves may twist, buckle, or distort.

Plants affected - artichoke, beans, beets, carrot, cucumber, eggplant, lettuce, melons, parsnips, peas, peppers, pumpkins, radicchio, radishes, squash, tomatillo, tomatoes, and turnips, etc.

Downy mildew affects the foliage. It's caused by a fungus-spreading through airborne spores. It infects plants during wet weather. 

Symptoms include: 

Light green to yellow angular spots on the upper surfaces of leaves

White fluffy growth on the lower sides of these spots

Lesions that turn brown and dry up over time

Older leaves are attacked first

Severely infected leaves may die

Black knot is a fungal disease that affects plants in the genus Prunus. It's caused by the fungus Apiosporina morbosa. 

Black knot is a common disease of plum and cherry trees, both fruiting and ornamental. 

The fungus overwinters in galls on branches and trunks. During wet periods in the spring, spores are released and carried by the wind to trees. The spores infect young green shoots or wounded branches. 

Black knot fungus isn't harmful to humans. 

Fungal blight causes plant tissues to rapidly turn brown, die, and decay. The disease is spread by fungal spores that are carried by wind, water, insects, and animals. The spores are deposited on soil and reproduce when they come into contact with moisture.

Examples of fungal blight: 

Leaf blight - tan or reddish-purple spots on sorghum leaves, which can merge into large lesions.

Early blight - common in tomatoes and potato foliage. 

Late blight - causes crop failures in potatoes if not controlled.

Fungal canker is a plant disease that occurs in woody species. It's caused by fungi that grow between the bark and wood of a tree, killing the living bark. Canker is a symptom of an injury, often an open wound, that has become infected by a fungal pathogen. 

Symptoms of canker include: 

Branches die

Structurally weakened plants

Sunken patches of dead bark

Clubroot is a fungal disease that affects plants in the cabbage family. It's caused by the soil-dwelling fungus Plasmodiophora brassicae. The disease gets its name from the club-like roots it causes in infected plants.

Symptoms of clubroot include: 

Roots: Large galls that look like clubs

Plants: Wilting, stunting, yellowing

Clubroot can cause plant death by impeding nutrient and water uptake.

Damping off is a disease that affects seedlings and can cause them to collapse. It's caused by several soil-borne fungi and fungus-like organisms. Damping off is more likely to occur in cool, wet conditions. It's especially a problem when sowing seeds indoors or under glass.

Symptoms of damping off include: 

Rotting of stem and root tissues

Water-soaked, mushy plants

Collapse at the base

Death

Fusarium wilt is caused by the soil-inhabiting fungus Fusarium oxysporum. The disease can cause significant yield losses in tomatoes. 

Symptoms include: 

Brown discoloration of xylem, Faded & wilted foliage, chlorosis & necrosis of leaves.

The fungus thrives in warmer weather and acidic soil. It enters plants through root wounds caused by cultivation or nematodes.

Plants affected - Sweet potatoes, Tomatoes, Legumes, Melons, Bananas, Eggplant, Pepper, Pigweed, Mallow, Crabgrass, and many more.

Dry rot is the most serious form of fungal decay. It attacks the timber in buildings, digesting the parts of the timber that give it its strength. It can spread without any source of moisture because it is able to generate moisture through the digestion of timber.

Signs:

A white cotton wool-like appearance that coats the affected timber like a cobweb

A distinctive type of cracking known as cuboidal cracking

A fruiting body that releases fresh spores into the surrounding air

Soft rot is a disease that affects the texture of plant tissue. It's caused by pathogens that secrete enzymes that break down cell walls, making the tissue soft and watery. 

Soft rot can occur in fleshy vegetables like potatoes, carrots, eggplants, and squash.

It a type of fungal decay that occurs when hyphae grow and penetrate the secondary cell walls of wood. 

Fungal rust is a plant disease caused by fungi in the genus Puccinia. Rust is a fungal plant pathogen that affects the aerial parts of plants. It usually appears as yellow, orange, red, rust, brown, or black powdery pustules on leaves, young shoots, and fruits.

Rust fungi are highly specialized plant pathogens with several unique features. They form a red or yellow-colored fungus on plants. Rust often needs two different plant species in order to complete its life cycle.

Fungal scab is a plant disease that causes crusty lesions on fruits, leaves, stems, or tubers. The term can also refer to the symptom of the disease.

Signs:

Pale or yellow spots on leaves

Dark, olive-colored spots on leaves, fruit, and stems

Velvety fungal growth on the undersurface of leaves

Twisted or puckered leaves

Yellow leaves

Premature leaf drop

Plants - Citrus, Cucumber, Apples, Crabapples, Cereals, Peaches, Pecans, Potatoes, Melons, Summer squash, Pumpkins, Winter squash.

Smut is a plant disease caused by a fungus. It's also known as Ustilago. Smut is a multicellular fungus with many teliospores.

Smut affects the aboveground parts of plants, such as: Leaves, Stems, Flowers. 

The fungus causes an enlargement, or gall, that's initially white and fleshy. As the fungus ages, it produces spores and turns into a black, powdery spore mass. The affected plants have a sooty, black appearance. 

Smut primarily affects grasses, such as: Corn, Wheat, Sugarcane, Sorghum. 

It can be yellow or black. 

 Symptoms of Sigatoka disease include: 

• Spots on the leaves
• Drying and defoliation of leaves
• Reduced fruit quality and yield
• Premature ripening of fruit bunches