Fundamentals of Plant Pathology

OUTLINE CLASSIFICATION OF FUNGI

Pseudofungi

Kingdom 1: Protozoa (uni-cellular microorganisms)

Phylum i: Myxomycota

Class: Myxomycetes (plasmodial slime moulds, do not infect plants)

Order: Physarales

Genera: Mucilago, Fulago, Physarum causing slime moulds in low lying plants)

Phylum ii: Plasmodiophoromycota (endoparasitic slime moulds)

Class : Plasmodiophoromycetes

Order: Plasmodiophorales

Genera: Plasmodiophora, P. brassicae causing club root of crucifers, Polymyxa, P. graminis on wheat and other cereals, and can transmit viruses, Spongospora, S. subterranea causing powdery scab of potato tubers

Kingdom 2: Chromista/ Straminopila (microorganisms unicellular or multi-cellular)

Phylum i: Oomycota (zoospores flagellate)

Class: Oomycetes (mycelium non-septate, sexual spores- oospores, asexual spores- zoospores)

Order: Peronosporales

Family: Peronosporaceae, (the downy mildews, sporangia borne on sporangiophores of determinate growth, obligate parasites)

Genera: Plasmopara, P. viticola causing downy mildew of grapes, Peronospora, P. tabacina causing downy mildew/ blue mould of tobacco), Bremia, B. lactucae causing downy mildew of lettuce, Pseudoperonospora, P. cubensis causing downy mildew of cucurbits; Sclerospora, S. graminicola causing downy mildew/ green ear disease of pearl millet

Family: Pythiaceae (sporangia, usually zoosporangia are produced along somatic hyphae, or tips of the hyphae of indeterminate growth and set free. OSogonia thin walled. Facultative parasites)

Genera: Pythium, P. debaryanum causing damping off of seedlings; Phytophthora, P. infestans causing late blight of potato

Family: Albuginaceae (the white rusts, sporangia borne in chains)

Genus: Albugo, A. candida causing white rust of crucifers

 

True Fungi

Kingdom 3: Fungi (produce mycelium, the walls of which contain glucans and chitin)

Phylum i: Chytridiomycota (produce zoospores with single posterior flagellum)

Class: Chytridiomycetes

Order: Chytridiales

Family: Olpidiaceae

Genera: Olpidium, O. brassicae being parasitic on roots of cabbage and other plants, and can transmit plant viruses; Physoderma, P. maydis causing brown spot of corn; Synchytrium endobioticum causing potato wart

Phylum ii: Zygomycota (produce non-motile spores in sporangia. Sexual spores are zygospores)

Class: Zygomycetes (bread moulds)

Order: Mucorales

Family: Mucoraceae

Genera: Rhizopus, R. stolonifer causing soft rot of fruits and vegetables; Choanephora, C. cucurbitarum causing soft rot of squash; Mucor causing bread mould and storage rots of fruits and vegetables)

Order: Glomales (the endomycorrhizae)

Genera; Glomus, Acaulospora, Gigaspora, Scutellospora

Phylum iii: Ascomycota (the sac fungi, produce ascospores)

Class i: Archiascomycetes

Order: Taphrinales (asci naked arising from binucleate ascogenous cells)

Family: Taphrinaceae

Genus: Taphrina, T. deformans causing peach leaf curl

Family: Protomycetaceae

Genus: Protomces, P. macrosporus causing stem gall of coriander

Class ii: Saccharomycetes (the yeasts, mostly unicellular fungi that reproduce by budding, asci naked, no ascocarps produced)

Order: Saccharomycetales

Family: Saccharomycetaceae

Genera: Galactomyces causing citrus sour rot; Saccharomyces, S. cerevisiae, the bread yeast

Class iii: Plectomycetes (ascomycetes with cleistothecia)

Order: Eurotiales

Family: Eurotiaceae

Genera: Eurotium, teleomorph of Aspergillus, causing bread mould and seed decay; Talaromyces, teleomorph of Penicillium, P. expansum causing blue mould rot of fruits

Order: Erysiphales (the powdery mildew fungi, asci formed in cleistithecia. mycelium, conidia, and cleistothecia produced on the host surface, obligate parasites)

Family: Erysiphaceae

Genera: Blumeria, B. graminis causing powdery mildew of cereals and grasses; Erysiphe cichoracearum causing powdery mildew of cucurbits; Leveillula, L. taurica causing powdery mildew of tomato and capsicum; Podosphaera, P. leuchotricha causing powdery mildew of apple; Sphaerotheca, S. pannosa causing powdery mildew of rose and peach; Uncinula, U. necator causing powdery mildew of grapes

Class iv: Pyrenomycetes (ascomycetes with perithecia)

Order: Hypocreales

Genera: Hypocrea rubra is the teleomorph of Trichoderma viride; Nectria galligena causing European canker of apple; Gibberella fujikuroi causing bakane/ foolish disease of rice; Claviceps purpurea causing ergot of grain crops

Order: Microascales

Genera: Ceratocystis, C. fagacearum causing oak wilt; C. fimbriata causing root rot of sweet potato, C. paradoxa causing butt rot of pineapple

Order: Phyllachorales.

Genera: Glomerella, G. cingulata (teleomorph of Colletotrichum sp.) causing many anthracnose diseases and bitter rot of apple; Phyllachora graminis causing leaf spot of grasses

Order: Ophiostomatales

Genera: Ophiostoma, O. novo-ulmi causing Dutch elm disease

Order: Diaporthales

Genera: Diaporthe, D. citri causing citrus melanose, D. vexans causing fruit rot of eggplant, Gnomonia leptostyla causing leaf blotch of walnut, Cryphonectria parasitica causing chestnut blight; Leucostoma (formerly Valsa) causing canker disease of peach and other trees

Order: Xylariales

Genera: Hypoxylon, H. mummatum causing severe canker of poplars; Rosellinia, R. necatrix causing root rot diseases of trees and vines; Xylaria, causing tree cankers and wood decay; Eutypa, E. armeniacae causing apricot canker

Class iv: Loculoascomycetes (ascomycetes with ascostroma or pseudothecium)

Order: Dothidiales

Genera: Mycosphaerella, M. musicola causing Sigatoka of banana, M. fragariae causing leaf spot strawberry; Elsinoe, E. fawcetti causing citrus scab, E. ampelina causing grape anthracnose

Order: Capnodiales

Genera: Capnodium, being one of the many fungi causing sooty moulds on the plants

Order: Pleosporales

Genera: Cochliobolus, the teleomorph of Helminthosporium or Bipolaris causing leaf spot diseases on many plants including C. miyabeanus causing brown spot disease of rice leading to the infamous Bengal famine, Pleospora, teleomorph of Stemphylium) causing black mould of tomato, Leptosphaeria, the teleomorph of Phoma causing black leg and foot rot of cabbage, Venturia, V. inaequalis causing apple scab and V. pirina causing pear scab, Guignardia bidwelli causing black rot of grapes

Class v: Discomycetes (ascomycetes with apothecia)

Order: Rhytismatales

Genera: Lophodermium, L. seditiosum causing pine needle cast, Rhytisma acerinum causing tar spot of maple leaves

Order: Helotiales

Genera: Monilinia, M. laxa, M. fructigena, M. fructicola causing brown rot of pome and stone fruits, Sclerotinia, S. sclerotiorum causing white mould and watery soft rot of vegetables, Stromatinia, S. gladioli causing corm rot of gladiolus, Diplocarpon, (the teleomorph of Marssonina), D. maculatum causing black spot of quince and pear, D. rosae causing black spot of rose, D. mali leaf blotch and premature leaf fall of apple

Class vi: Deuteromycetes or mitosporic fungi (imperfect fungi): Sexual reproduction or structures rare, lacking or unknown.

Phylum iv. Basidiomycota (basidiomycetes, the club and mushroom fungi)

Class i: Urediniomycetes (rust fungi)

Order: Uredinales

Family: Pucciniaceae

Genera: Puccinia, P. graminis tritici causing black rust of wheat, P. recondita causing brown rust of wheat, P. striiformis causing yellow rust of wheat, P. dianthii causing rust of carnation. Gymnosporangium, G. juniperi-virginianae causing cedar apple rust; Cronartium, C. ribicola causing rust of pine; Hemileia, H. vastatrix causing coffee rust; Melampsora, M. lini causing flax rust; Phragmidium, P. mucronatum causing rose rust; Uromyces, U. appendiculatus causing rust of bean

Class: Ustilaginomycetes (smuts and bunts)

Order: Ustilaginales

Family: Ustilaginaceae

Genera: Ustilago, U. tritici causing loose smut of wheat, U. maydis causing corn smut, U. nuda, causing smut of barley; Urocystis, U. cepulae causing smut of onion

Family: Tilletiaceae

Genera: Tilletia, T. caries and T. foetida causing hill bunt of wheat, T. (Neovossia) indica causing Karnal bunt of wheat

Class: Basidiomycetes (earlier grouped under hymenomycetes and gasteromycetes) produce basidiospores, basidia and basidiocarps)

Order: Exobasidiales (no fruiting bodies or basidiocarps)

Family: Exobasidiaceae

Genera, Exobasidium, E. vexans causing blister blight of tea

Order: Ceratobasidiales

Genera: Athelia, the teleomorph of Sclerotium, S. rolfsii causing southern blight and root rot of many plants, S. cepivorum causing the white rot onion; Thanatephorus, T. cucumrris , the teleomorph of Rhizoctonia solani, causing root rot and web blight of many plants; Typhula, causing Typhula blight or snow mould of turf grasses

Order: Agaricales (the mushrooms)

Family: Agaricaceae

Genera: Agaricus, A. bisporus , the white button mushroom; Armillariella (Armillaria) mellea causing root rot of trees; Marasmius, causing fairy ring disease of turf grass, Pleurotus, causing white rot on logs, tree stumps and living trees; Pholiota, causing brown wood rot in deciduous forest trees

Family: Pluteaceae

Genus: Amanita, A. muscaria, the fly agaric is a poisonous mushroom

Family: Lycoperdaceae

Genus: Lycoperdon, the puff balls

Order: Phallales

Family: Geastraceae

Genus: Geastrum, the earth stars

Order: Aphyllophorales

Genera: Chondrostereum, C. purpureum causing the silver leaf disease of trees, Corticium, C. salmonicolor causing pink disease in many fruit and other trees; Heterobasidion, H. annosus causing root and butt rot of many trees; Ganoderma, G. lucidum causing root and basal rot in many trees; Phelinus, causing tree root rot and cubical rots in buildings; Peniophora, P. gigantea causing decay in coniferous logs and pulpwood; Polyporus, P. squamosus causing heart rot of many forest trees