Encyclopedia - Small Grains

Use the Search and Filter options to help select only the crops, types of disease, and timing of disease you are interested in from the list below. Only articles meeting your chosen criteria will be shown. These articles contain information and images for identification and basic management of crop diseases.

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Aster Yellows of Wheat

Aster yellows is caused by a phytoplasma spread by leafhoppers during feeding. Leafhopper feeding can cause white flecking or stippling on leaves. When the plant is infected, leaves become yellowish and progressively turn red-brown or purple, usually starting at the tips. Discoloration typically occurs as streaks. Plants may be stunted and... Read More

Bacterial Leaf Blight of Wheat

Bacterial leaf blight is not of major economic importance in wheat. After prolonged periods of high humidity, water-soaked spots develop on flag leaves and below on infected plants. Affected areas can range from small flecks to large blotches on leaves. Once humidity decreases, spots will turn gray/green, become tan and... Read More

Bacterial Streak and Black Chaff of Wheat

Bacterial streak appears first as small water-soaked lesions that rapidly develop into long, thin, tan-brown, water-soaked lesions, confined between the leaf veins. Lesions may appear translucent when backlit, especially when leaves are wet. Unless leaves remain wet or there is high humidity, the water-soaked... Read More

Barley Yellow Dwarf of Wheat

Barley yellow dwarf is widespread throughout the U.S. and Canada and can affect a variety of cereal crops. It is caused by multiple viruses. Symptoms of barley yellow dwarf (BYD) include stunting; yellow, red, and/or purple discoloration of leaves (particularly the flag leaf); and tip burn. Leaves can be distorted and roots underdeveloped. S... Read More

Black Head Molds of Wheat

The various fungi that cause black head mold primarily live on dead plant tissue and are typically only a problem when wheat dies prematurely. Also known as sooty head molds, black head molds appear dirty and come in a variety of colors (black, white, pink, or green) depending on the causal fungi. Growing on dead leaves, stems, and heads, these fungi are of most concern w... Read More

Black Point of Wheat

Black point does not typically cause yield loss, but reduces grain quality. It is caused by several pathogens. As the name implies, kernels that develop black point will have a black, smudge-like discoloration. This typically occurs at the proximal or embryo end of the kernel. Symptoms can be obs... Read More

Cephalosporium Stripe of Wheat

The fungus that causes Cephalosporium stripe infects wheat below ground in fall and winter. This results in stunting and dead standing stems called white heads. Early symptoms include a chlorotic mottle appearing as the plant breaks dormancy in spring. As the plant matures, one to three distinct, yellow stripes appear near leaf veins. Stripe... Read More

Cereal Cyst Nematode of Wheat

Cereal cyst nematodes are some of the most economically damaging nematodes to wheat production. Most small grain cereals and some grasses are hosts. Common symptoms on wheat include stunting and poor plant growth appearing in patches across a field, reduced number of tillers, and plants appearing more yellow than surrounding healthier plants. Cl... Read More

Common Bunt of Wheat

Common bunt is also known as covered smut or stinking smut, and reduces yield and grain quality. Though historically important, current management practices typically prevent major losses. Evidence of common bunt is rarely present before ripening, but some stunting may occur. As heads ripen (FGS 10.5.3), spikelets may develop a... Read More

Common Root and Foot Rot of Wheat

Common root and foot rot occurs in all wheat production areas of the U.S. and Canada. The causal pathogen has a wide host range and also causes a foliar disease known as spot blotch. Symptoms include dark, chocolate brown to black lesions on the coleoptile, stem, roots, and/or subcrown internode (the area above the seed to the soil line). Heavily... Read More

Dwarf Bunt of Wheat

Dwarf bunt is also known as dwarf smut. It typically occurs with long periods of snow cover, and only impacts winter wheat. Symptoms prior to heading (FGS 10.5) include yellow leaf flecking at late seedling stage, stunting, and excessive tillering. Once the head emerges, the fungus transforms kernels in... Read More

Ergot of Wheat

Ergot has played an important role in history as it impacts human and animal health. Though less problematic today, the disease can still cause issues, particularly in male-sterile wheat lines. During early infection, some kernels go through a "honeydew" stage where infected ovaries swell and emit a yellow, slime-like fluid. This fluid attracts insects and is full of spores. Ova... Read More

Eyespot of Wheat

Eyespot, also called strawbreaker foot rot, can cause yield losses up to 50%. Winter wheat is affected more than spring wheat because environmental conditions are more conducive. Symptoms appear on stems directly above or below the soil surface. Stems develop a light tan to yellow-brown, eye-shaped l... Read More

Fusarium Head Blight of Wheat

Fusarium head blight (FHB) is currently the most economically important wheat disease in the U.S. and Canada. This disease is also known as scab or head blight. It reduces yield and produces mycotoxins that impact human and animal health. Infected spikelets are bleached and disease spreads upward and downwar... Read More

Fusarium Root, Crown, and Foot Rot of Wheat

Fusarium root, crown, and foot rot of wheat is widespread and can be found in all wheat production regions of the U.S. and Canada. Seedling blight occurs when Fusarium-infected seed is sown. Infected seedlings tend to be reddish with poor vigor and poor tiller production. Root, crown, and foot rot symptoms include da... Read More

Leaf Rust of Wheat

Leaf rust, also called brown rust, occurs across the U.S. and Canada and can cause severe yield loss in epidemic years. Leaf rust pustules rupture the leaf epidermis, but lack conspicuous tear marks. These pustules contain orange-brown, rusty colored spores. Later in the season, dark brown to black spores are produced whic... Read More

Loose Smut of Wheat

Loose smut has a wide distribution and can occur anywhere wheat is produced. Mild symptoms may be present prior to heading, including yellowish leaf streaks and stiff, dark green leaves. Affected plants head out early, producing sterile heads with clumped, sooty olive-black spores in place of healthy glumes and kernels. Spores are... Read More

Powdery Mildew of Wheat

Powdery mildew is a common disease of wheat throughout the U.S. and Canada wherever winter wheat is grown. It is an economic problem primarily in the eastern soft winter wheat region. The characteristic sign of the powdery mildew pathogen is fluffy, white to gray fungal growth on the top surface of leaves. Yellowish spots b... Read More

Pythium Root Rot of Wheat

Pythium root rot is a soil-borne disease that reduces yield in wheat growing regions throughout the U.S. and Canada. Symptoms include stunting, yellowing, tiller reduction, and poor stand. Symptoms are generally more noticeable in low lying areas. Infected roots are shorter, have few root hairs, and are necrotic. The... Read More

Rhizoctonia Root Rot of Wheat

Rhizoctonia root rot of wheat occurs in temperate regions and is also called bare patch. Field symptoms include bare patches or areas of uneven plant height. Severe infection causes plants to be stunted, appear drought stressed or nutrient deprived, and may result in premature plant death. Mild infection may go unnoticed abov... Read More