Wheat diseases
Encyclopedia
In Europe
Cereals are at risk from numerous diseases due to the level of intensification necessary for profitable production since the 1970s. More recently varietal diversification, good plant breeding and the availability of effective fungicides have played a prominent part in cereal disease control. Use of break crops and good rotations are also good cultural control measures. The demise of UK straw burning in the 1980s also increased the importance of good disease control.Active control measures include use of chemical seed treatments for seed-borne diseases and chemical spray applications for leaf and ear diseases. Development of resistance by diseases to established chemicals has been a problem during the previous 30 years.
Fungicides
Some cereal fungicide groups and examples of active ingredients:- Benzimidazoles
- carbendazimCarbendazimCarbendazim is a widely used broad-spectrum benzimidazole fungicide. A 4.7% solution of carbendazim hydrochloride is sold as Eertavas, an effective treatment for Dutch elm disease....
- carbendazim
- Ergosterol biosynthesis inhibitors
- prochloraz
- flutriafol
- tetrachonazole
- MorpholineMorpholineMorpholine is an organic chemical compound having the chemical formula O2NH. This heterocycle, pictured at right, features both amine and ether functional groups. Because of the amine, morpholine is a base; its conjugate acid is called morpholinium...
s- fenpropimorph
- Strobylurines
- kresoxim-methyl
- PhthalonitrilePhthalonitrilePhthalonitrile is an organic compound with the formula C6H42, which is an off-white crystal solid at room temperature. It is a benzene derivative, containing two adjacent nitrile groups. The compound is partially soluble in water, and is soluble in acetone, nitrobenzene, and benzonitrile...
s- chlorothalonilChlorothalonilChlorothalonil is a polychlorinated aromatic mainly used as a broad spectrum, non-systemic fungicide, with other uses as a wood protectant, pesticide, acaricide, and to control mold, mildew, bacteria, algae. Chlorothalonil-containing products are sold under the names Bravo, Echo, and Daconil. It...
- chlorothalonil
Principal diseases
- Barley yellow dwarf virus, BYDV
- Brown rust Puccinia reconditaPuccinia reconditaPuccinia recondita is a plant pathogen.- External links :* *...
- Common buntCommon buntCommon bunt, also known as stinking smut and covered smut is a disease of both spring and winter wheats. It is caused by two very closely related fungi, Tilletia tritici and T. laevis Common bunt, also known as stinking smut and covered smut is a disease of both spring and winter wheats. It is...
(aka Covered smut) Tilletia cariesTilletia cariesTilletia caries is a plant pathogen that infects wheat causing the disease bunt. Plants infected with the disease are often slightly stunted, occasionally with yellow streaks on the flag leaf. Grain is replaced with bunt balls containing masses of black spores. At ripening, the ears take longer to... - ErgotErgotErgot or ergot fungi refers to a group of fungi of the genus Claviceps. The most prominent member of this group is Claviceps purpurea. This fungus grows on rye and related plants, and produces alkaloids that can cause ergotism in humans and other mammals who consume grains contaminated with its...
Claviceps purpureaClaviceps purpureaClaviceps purpurea is a fungus that grows on the ears of rye and related cereal and forage plants. Consumption of grains or seeds contaminated with the fruiting structure of this fungus, the ergot sclerotium, can cause ergotism in humans and other mammals.. C... - Eyespot Pseudocercosporella herpitrichoidesTapesia yallundaeTapesia yallundae is the causal agent for a variety of cereal and forage grass diseases. The anamorph o f T. yallundae is the W-type strain of Pseudocercosporella herpotrichoides...
- Glume blotch Septoria nodorum plus Septoria triticiSeptoria triticiSeptoria tritici is the causal agent of S. tritici leaf blotch, a foliar disease of wheat, and occasionally infects other grasses including barley...
- Leaf blotch Septoria tritici
- MildewMildewMildew refers to certain kinds of molds or fungi.In Old English, it meant honeydew , and later came to mean mildew in the modern sense of mold or fungus....
Erysiphe graminis - Seedling blight FusariumFusariumFusarium is a large genus of filamentous fungi widely distributed in soil and in association with plants. Most species are harmless saprobes, and are relatively abundant members of the soil microbial community. Some species produce mycotoxins in cereal crops that can affect human and animal health...
spp., Septoria nodorum - Sharp eyespot Rhizoctonia cerealis
- Spot blotchSpot blotch (wheat)Spot blotch is a leaf disease of wheat caused by Cochliobolus sativus. Cochliobolus sativus also infects other plant parts and in conjunction with other pathogens causes common root rot and black point.-Introduction:...
Biplolaris sorokianaCochliobolus sativusThe fungus Cochliobolus sativus is the teleomorph of Bipolaris sorokiniana which is the causal agent of a wide variety of cereal diseases. The pathogen can infect and cause disease on the root , leaf and stem, and head tissue... - Take-allTake-allTake-all is a plant disease affecting the roots of cereal plants in temperate climates caused by the fungus Gaeumannomyces graminis var. tritici. All varieties of wheat and barley are susceptible...
Gaeumannomyces graminis - Tan spot Pyrenophora tritici-repentisPyrenophora tritici-repentisPyrenophora tritici-repentis is a plant pathogen of fungal origin, causing a disease called tan spot or helminthosporiosis, that affects mainly wheat in its more common varieties. It forms characteristic, dark, oval-shaped spots of necrotic tissue surrounded by a yellow ring...
- Yellow rust Puccinia striiformis
In the USA
Wheat is subject to more diseases than other grains, and, in some seasons, especially in wet ones, heavier losses are sustained from those diseases than are in other cereal crops. Wheat may suffer from the attack of insects at the root; from blight, which primarily affects the leaf or strawStraw
Straw is an agricultural by-product, the dry stalks of cereal plants, after the grain and chaff have been removed. Straw makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has many uses, including fuel, livestock bedding and fodder, thatching and...
, and ultimately deprives the grain of sufficient nourishment; from mildew on the ear; and from gum of different shades, which lodges on the chaff or cups in which the grain is deposited.
Bacterial diseases
- Bacterial leaf blightBlightBlight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. It is simply a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Accordingly, many diseases that primarily exhibit this...
Pseudomonas syringaePseudomonas syringaePseudomonas syringae is a rod shaped, Gram-negative bacterium with polar flagella. It is a plant pathogen which can infect a wide range of plant species, and exists as over 50 different pathovars, all of which are available to legitimate researches via international culture collections such as the...
subsp. syringae - Bacterial sheath rot Pseudomonas fuscovaginaePseudomonas fuscovaginaePseudomonas fuscovaginae is a fluorescent, Gram-negative soil bacterium that is pathogenic to rice, causing brown sheath rot. The type strain is CCUG 32780....
- Basal glume rot Pseudomonas syringaePseudomonas syringaePseudomonas syringae is a rod shaped, Gram-negative bacterium with polar flagella. It is a plant pathogen which can infect a wide range of plant species, and exists as over 50 different pathovars, all of which are available to legitimate researches via international culture collections such as the...
pv. atrofaciens - Black chaff = bacterial streak Xanthomonas campestris pv. translucens
- Pink seed Erwinia rhapontici
Fungal diseases
- Alternaria leaf blight Alternaria triticinaAlternaria triticinaAlternaria triticina is a plant pathogen that causes leaf blight on wheat. It was first identified in India in 1962 and still causes significant yield loss to wheat crops on the Indian subcontinent. The disease causes necrotic leaf lesions and in severe cases seeds will become shriveled....
- Anthracnose Colletotrichum cereale Manns
- Ascochyta leaf spot Ascochyta tritici
- Black head molds = sooty molds Alternaria spp., Cladosporium spp.
- Common bunt = stinking smut T. tritici, T. laevis
- Downy mildewWheat mildewWheat mildew is a wheat disease that affects the ear, and is brought on by causes somewhat similar to those that cause blight, though at a more advanced period of the season. If this disorder comes on immediately after the first appearance of the ear, the straw is also affected—but if the...
= crazy top Sclerophthora macrospora - Dwarf bunt Tilletia controversa
- Ergot Claviceps purpurea
- Foot rot = dryland foot rot Fusarium spp.
- Leaf rust = brown rust Puccinia triticina
- Leaf and glume blotch, Stagonospora nodorum or Phaeosphaeria nodorum
- Pink snow mold = Fusarium patchFusarium patchFusarium patch is a disease in turf grass settings called pink snow mold, Microdochium patch or Fusarium patch. Microdochium nivale is the pathogen that causes this disease in many cool season turf grass species in North America. The white-pink mycelium on infected leaf blades is a distinguishing...
Microdochium nivale - Powdery mildewPowdery mildewPowdery mildew is a fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of fungi in the order Erysiphales. It is one of the easier diseases to spot, as its symptoms are quite distinctive. Infected plants display white powdery spots on the...
= Blumeria graminis - ScabFusarium ear blightFusarium ear blight , is a fungal disease in plants. It is responsible for the most common damaging disease that affects golf course grass. From an economic stand point, it is one of the major cereal diseases, being responsible for significant grain yield reduction in wheat and oats...
= head blight Fusarium spp., Gibberella zeae, - SeptoriaSeptoriaSeptoria are Ascomycete fungi that causes numerous leaf spot diseases on field crops, forages and many vegetables, and is responsible for yield losses...
blotch Septoria tritici = Mycospharella graminicola, - SmutSmut (fungus)The smuts are multicellular fungi, that are characterized by their large numbers of teliospores. The smuts get their name from a Germanic word for dirt because of their dark, thick-walled and dust-like teliospores. They are mostly Ustilaginomycetes and can cause plant disease...
= Ustilaginomycotina clade of the class Teliomycetae, subphylum BasidiomycotaBasidiomycotaBasidiomycota is one of two large phyla that, together with the Ascomycota, comprise the subkingdom Dikarya within the Kingdom Fungi... - Storage moulds Aspergillus spp., Penicillium spp.
- Wheat mildewWheat mildewWheat mildew is a wheat disease that affects the ear, and is brought on by causes somewhat similar to those that cause blight, though at a more advanced period of the season. If this disorder comes on immediately after the first appearance of the ear, the straw is also affected—but if the...
- Wheat leaf rustWheat leaf rustWheat leaf rust, is fungal disease that effects wheat, barley and rye stems, leaves and grains. In temperate zones it is destructive on winter wheat because the pathogen overwinters. Infections can lead up to 20% yield loss - exacerbated by dying leaves which fertilize the fungus. The pathogen is...
- Wheat stem rust
Nematodes, parasitic
- Grass cyst nematodeNematodeThe nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
Punctodera punctata - Root gall nematode Subanguina spp.
Viral diseases and viruslike agents
- Agropyron mosaic genus Rymovirus, Agropyron mosaic virus (AgMV)
- Barley stripe mosaic genus Hordeivirus, Barley stripe mosaic virus (BSMV)
- Oat sterile dwarf genus Fijivirus, Oat sterile dwarf virus (OSDV)
- Tobacco mosaic genus Tobamovirus, Tobacco mosaic virusTobacco mosaic virusTobacco mosaic virus is a positive-sense single stranded RNA virus that infects plants, especially tobacco and other members of the family Solanaceae. The infection causes characteristic patterns on the leaves . TMV was the first virus to be discovered...
(TMV) - Wheat dwarf genus Monogeminivirus, Wheat dwarf virus (WDV)
- Wheat yellow mosaic Wheat yellow mosaic bymovirus
Link between air pollution and septoria blotch
A team of researchers examined a library of British wheat samples dating back to 1843. For each year, they determined the levels of Phaeosphaeria nodorum and Mycospharella graminicola DNADNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
in the samples. After accounting for influences such as growing and harvesting methods and weather conditions, they compared the DNA data with estimates of emissions of air pollutants. The effect of sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
correlated with the abundance of the two fungi. P. nodrum grew more successful with the dawn of the Industrial Revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...
. M. graminicola was more abundant before 1870 and since the 1970s. The success since the 1970s may be linked to reductions in sulfur dioxide emissions due to environmental regulations. (Bearchell, et al., 2005)
External links
- Wheat Diseases and Pests: A Guide for Field Identification Excellent color guide from CIMMYT
- USDA Cereal Disease Laboratory Many information resources
- Identifying and Managing Wheat Rusts, Kansas State University