"Across species"

A haploid, dikaryotic spore produced by basidiomycetes in an aecium. Present in macrocyclic rusts. Travel from the host bearing aecia to the host bearing telia.

Honey mushroom

A basidiomycetes pathogen that causes armillaria root rot in angiosperms.

Symptoms include branch dieback, crown thinning, basal cankers above the roots, decayed roots, and resinosis. In conifers there may be chlorosis or reddening of foliage, and stress crop of cones. Wood has white rot, where lignin and polysaccharides are degraded, and remaining cellulose gives wood a fibrous texture. Black zone lines of fungal cells may be seen in the wood. Actively decaying wood may have bioluminescence in the dark.

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Sac fungi

A group classified on sexual structures. Ascospores are produced on asci produced in naked asci, chasmothecia, perithecia, or apothecia. Conidia are produced on simple conidiophores or pycnidia.

An autoecious rust disease. Affects asparagus.

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"Self house"

Monoecious rust

Rusts with one host. Includes asparagus rust.

Club fungi

Most are fleshy fungi, either saprophytes or causing wood decay. Non-pathogenic groups include mushrooms, puffballs, and shelf fungi. Pathogenic groups include smuts, rusts, and species of Rhizoctonia, Armillaria, and Typhula. Produce basidiospores, spermatia, aeciospores, urediospores, and teliospores. Some spore stages can infect alternate hosts.

Mnemonic for spores: BPAUT

Sporidia

"Bring it on!"

A haploid, monokaryotic sexual spore produced by basidiomycetes in a basidium. Found in macrocyclic and microcyclic rusts. Usually forcibly ejected by the sterigmata, traveling a few micrometers. Often produced in the spring. Small in size, and can travel on wind and water. Germinates on hosts, generating primary mycelium.

"Club"

A club-shaped structure in basidiomycetes that germinates from a teliospore. Diploid and monokaryotic. Undergoes meiosis to produce four basidiospores on sterigmata which forcibly eject them. Similar production process to ascospores, but there is no mitosis event after meiosis.

Aecia form on the lower surface of the leaf, with a "flower" appearance due to shredding of the peridium membrane.

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Gelatinous telial horns appear in the summer after infection.

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A gymnosporangium rust caused by Gymnosporangium clavipes. Infects the stems and fruits of hawthorn. Aecia form on fruits, and the peridium does not shred; it remains intact, shaped like a straw through which aeciospores are shot.

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A disease caused by Puccinia sorghi.

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Blister smut

Boil smut

Common smut

Corn mushroom

Corn truffle

Mexican caviar

A potentially polycyclic, mostly monocyclic disease caused by Ustilago maydis. Occurs wherever corn is grown. Reduces yield by an average of 2%, but can approach 100% in individual fields. It first spread to Australia in 1911, where it remained localized in Bathurst for many years due to quarantine efforts, however it spread to other regions in 1996. Economic losses in the USA have been minor since development of resistant hybrids in 1940. Loss is greatest when infection occurs in young plants, where it can lead to plant death. It is of greater consequence in sweet corn, since even a small amount of disease makes an ear unmarketable. It is edible as cuitlacoche.

Tissues may appear chlorotic before galls form. Mycelia stimulate cell division and enlargement, and loss of vasculature, producing a gall, 1 - 30 cm in diameter. Galls are noticeable 10 - 14 days after infection, found on ears, tassels, stalks, nodal shoots, and mid-ribs of leaves. Young plants may have galls in the root as well as the shoot, and the plant remains stunted or dies. At first galls are firm, and have a greenish-white, semi-glossy perdierm. The interior then becomes semi-fleshy, and streaks of black tissues occur, then galls become a mass of powdery teliospores, 16 - 18 days after infection. At 21 - 23 days the peridum ruptures and galls become sloppy, wet, masses of teliospores that are sooty and powdery when dehydrated. A single gall may produce 200 billion spores.

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Common bunt

Stinking smut

A disease caused by Tilletia sp. Managed by using certified smut-free seed, or hot water seed treatment.

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A disease caused by Ustilago hordei.

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A disease caused by Puccinia coronate f.sp. avenae. Affects oats and barley.

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Huitlacoche

The young, edible galls of corn smut on ears of corn. A highly prized delicacy in Mexico, eaten since pre-Columbian times. Each year, 400 - 500 tons are sold fresh, and over 100 tons are processed and/or canned. It is served in soups, appetizers, and entrées.

Snow scald

Speckled snow mould

Typhula blight of turfgrass

Winter scald

A disease caused by Typhula ishikariensis and T. incarnata. Affects golf fields.

Patches appear in the spring after snowmelt, with scalded or bleached appearance, 10 - 25 cm in diameter, often overlapping to form larger irregular patches. Patches may be larger on taller-mown turf. Patches have white fluffy mycelia at the edges, and are matted and bleached in the centre. Once patches are visible, the fungus is not longer active. Sclerotia may be found on dead leaf blades after snow melt.

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A gymnosporangium rust.

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A disease caused by Sphacelotheca reilana. Affects corn. Apeared in Ontario in 1979, and spread to Quebec. Not as common as corn smut. Symptoms are similar to corn smut, but teliospores can be distinguished under a microscope. Floral structures are converted into sori containint masses of powdery teliospores in which vascular bundles of the host are usually present as thread-like structures.

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"Different house"

Rusts with two alternating hosts. Includes wheat stem rust and white pine blister rust.

Early in the spring, orange pustules form on the underside of leaves. Pustules contain teliospores, and turn ash-grey when they germinate into basidiospores a few days or weeks later.

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A gymnosporangium rust.

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A gymnosporangium rust.

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"Kernel marriage"

Fusing together of two haploid eukaryotic cells. Occurs in teliospores, followed by meiosis.

Brown rust

A disease caused by Puccinia triticina. Affects wheat, barley, and rye.

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A disease caused by Ustilago nuda. Symptoms are seen as dense heads emerging from the boot. Kernels and glumes form as black masses of teliospores which blow away, leaving the rachis bare.

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A disease caused by Ustilago tritici. Symptoms are seen as diseased heads emerging from the boot. Kernels and glumes form as black masses of teliospores which blow away, leaving rachis bare. Plants are infected during flowering.

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A disease caused by Urocystis cepulae. Affects onions and related crops. The flag leaf is infected, and black-brown streaks and blisters appear in the leaves and small bulbs later in the growing season. As lesions mature, they turn brown and contain a mass of dark powdery spores, giving tops a sooty appearance. Darkened bulbs contain teliospores.

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Symptoms vary considerably. Common symptoms include pre- and post-emergence damping off, root and stem rots, and cankers of growing and mature plants. Symptoms are more severe when plant growth is slow due adverse conditions.

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Rhizoctonia stem rot

A common rhizoctonia disease caused by Rhizoctonia solani. Affects many crops, including soybeans, corn, and alfalfa. Typically damages seedlings. Can result in significant yield loss. Symptoms are rust-brown, dry, sunken lesions on stems and roots near the soil line. Lateral roots may decay. Plants may become stunted, yellow, and wilted. Lesions can girdle the stem and kill or stunt plants. Favoured by high soil moisture and warm temperatures, and delayed emergence. Plant stresses such as herbicides make plants more susceptible. Managed with good agronomic practices, high quality seed, crop rotation, and seed treatments. Some cultivars have greater tolerance.

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Hyphae sterilia

Mycelia sterilia

Also known by its sexual stage with multinucleate cells, Thanatephorus sp., or with binucleate cells, Ceratobasidium sp. A basidiomycetes pathogen that causes rhizoctonia diseases. Produces no aseuxal spores, and rarely produces basidiospores. Produces mycelia only in culture. Hyphae develop in branches at right angles to parent hyphae. There is a slight constriction and cross-wall at the junction of a branch and parent hyphae.

A rhizoctonia disease. Causes significant damage in cool, wet soils. Symptoms include delayed or reduced emergence, stunting of plants, smaller and/or deformed tubers, underground stem or stolon cankers, and reduced yield. The pathogen survives in plant residues and soil as mycelia and sclerotia. Sclerotia can survive on the surface of potato tubers without causing symptoms.

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Formae specialis

Rust fungi that are morphologically identical, but attack different host genera. Within these forms, there may be races.

Pycniospore

"Partners meet"

A haploid, monokaryotic spore produced by basidiomycetes in a spermatogonium. Present in macrocyclic rusts. They apepar similar to sperm. Water is needed for them to meet and fertilize receptive hyphae, fusing to produce haploid, dikaryoitc hyphae.

Pycnium

A structure in basidiomycetes which produces spermatia, and has receptive hyphae for spermatia fertilization. Resembles a pyncidium.

A disease caused by Puccinia graminis f.sp. tritici and P. graminis f.sp. secalis.

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A disease caused by Puccinia graminis f.sp. avenae.

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Yellow rust

A disease which affects wheat.

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"Take a break"

A diploid, monokaryotic spore produced by basidiomycetes in a telium. Produced by macrocyclic and microcyclic rusts. During production there is karyogamy of haploid nuclei in the telium, producing a diploid zygote. Many rusts overwinter in this form; they are the longest-lasting spore of basidiomycetes. Germinates to produce a basidium.

"Until summer's end"

A haploid, dikaryotic spore produced by basidiomycetes in a uredium. Present in macrocyclic rusts. Act as a secondary inoculum to the host bearing uredia. Often orange in colour, giving the name "rust".

Black stem rust

A polycyclic, heteroecious, macrocyclic rust disease caused by Puccinia graminis f.sp. tritici. Results in 1 million metric tons of lost yield per year, in severe years 100s of millions of tons. In 1943 - 1969, the USA and USSR produced strains of it to be used as biological weapons. The disease was classified, dried, and stored in Fort Detrick and the Rocky Mountain Arsenal; these agents were tested at least 31 times by the US military.

All aboveground parts can be affected. Fewer tillers are produced. Fewer seeds set per head. Smaller kernel size, usually shriveled with poor quality. Severe infections can result in lodging or plant death. Reddish structures which are uredia form at points of infection, which turn into black pustules as the plant matures.

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Galls form on branches which contain discrete black bodies beneath the bark which are spermatogonia. Ooze is secreted from the galls, containing spermatia. After fusion of receptive hyphae, white blisters break through the bark, containing aecia.

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