Basidiomycetes Flashcards
Basidiomycetes, aka…
“club” fungi
Basidium
Where basidiospores are produced
Orders of Importance
Ustilaginales
Uredinales
Ustilaginales
- Smuts
- Disease looks like soot
- Two spore types:
basidiospores (N)
teliospores (N+N)
Uredinales
- Rusts
- Five spore types
Smut Genera
- Ustilago
- Tilletia
- Splacelotheca
Characteristics of Smuts
- worldwide
- Conspicuous…
Fungus replaces seed
Produces black spores
(Some attack stems / leaves) - Fastidious = fussy! hard to grow in culture
Smut in seedlings
Attacks young tissue, entire seedling is colonized. As plant matures, fungus replaces embryo (flower) with spores… OW as teliospores in plant debris. Mgt - resistance, seed trt, systemic fungicides
ex. covered smut, bunt, head smut of corn
Localized Smut
Attacks anywhere on plant
ex. common smut of corn
Embryo Infection of Smut
Directly attacks embryo / flower… replaces embryo, then seed -> spores are produced. Seed infestation.
ex. louse smut
Corn Smut causal organism
Common - Ustilago zeae
Head - Splacelotheca reilana
Corn Smut host range
Corn and closest relatives
Corn Smut geo
Wherever corn is grown
Corn Smut symptoms
None!
Corn Smut signs
Common - whitish / greyish galls or swelling anywhere on plant. Swellings darken, rupture… release black teliospores.
Head - kernels replaced with swellings. Swellings darken, rupture… release black teliospores.
Difference = where disease occurs initially
Corn Smut disease cycle
Monocyclic
OW - teliospores (N+N) in debris (common), harvested seed (head)
Germinate -> basidiospores (N), wind-borne (common), infected seedling (head)
Infection - anywhere (common), grows with plant (head)
Signs … OW
Corn Smut management
Not much to do.
Common - erratic, cannot predict.
Head - resistance, seed trt, actually a delicacy in some countries (truffle)
Characteristics of Rusts
- Among most destructive plant diseases… attack mostly leaves / stems.
- Some need two unrelated hosts to complete life cycle (heteroecious), some need only one (autoecious)
- Five spore forms in MACROCYCLIC life cycle:
- teliospores
- basidiospores
- spermatia
- aeciospores
- urediniospores
MICROCYCLIC - missing one or more spore forms
Rust signs
Yellowish, reddish spores
Black spores
Rust symptoms
Orangish, yellowish spots usually on leaves
Galls
Rust teliospores
(N+N), overwintering
Rust basidiospores
(N), dispersed, produced in layers and exposed to air before shooting off
Rust spermatia
Male gametes, only purpose is to fertilize
Rust aeciospores
(N+N), result of sexual process (union of spermatia with receptive hyphae)
Rust urediniospores
Repeating spores, dispersed
Wheat stem rust
Puccinia graminis f. sp. tritici
Wheat and barberry (heteroecious)
- urediniospore on wheat
- teliospores
- macrocyclic rust
Cedar apple rust
Gymnosporangium juniperi-virginianae
Cedar and apple (heteroecious)
- no urediniospores
- microcyclic
Coffee rust
Hemileia vastatrix
autoecious, polycyclic, microcyclic
- urediniospores on coffee
- basidiospores germinate
White pine blister rust
Cronartium ribicola
Ribes (gooseberry, currants) as alt host
- urediniospores on ribes
Fusiform gall rust on Southern pine
Cronartium quercuum f. sp. fusiforme
Oak is alt host
Daylily rust
Puccinia hemerocallidis
Asparagus rust
Puccinia asparagi
Carnation rust
Uromyces dianthi
Coffee Rust losses
Decreased vigor, longevity, photosynthetic capacity
This year’s disease affects next year’s losses
Severe infection -> twig / branch death
Coffee Rust favorable conditions
59-82°F
wet conditions for spore germination, driven by rain more than wind
occurs continually due to year-round growth
Coffee Rust management
Resistance
Quarantine (past)
- Sri Lanka, 1867… ~100 years until in Americas
Cultural practices
- increase air flow
- avoid excess water / nitrogen
Fungicides
Soybean Rust
Asian - Phakospora pachyrhizi
- no resistance, watching for arrival in US
American - Phakospora meibromiae
- not as destructive
Must blow into soybean crop to infect (takes weeks or months) -> hits around maturity
Exobasidiales
No basidiocarp, basidiospores produced on surface of parasitized tissue
Exobasidium causes leaf galls of azalea / camelia
Ceratobasidiales
Weblike basidiocarp, inconspicuous, “sterile” fungi (no spores)
Thanatephorus
Rhizoctonia spp. - root rots
Rhizoctonia root rot / Large Patch of Turf causal organism
Rhizoctonia solani and other species
Rhizoctonia root rot / Large Patch of Turf host
most plants of interest to man, esp herbaceous annuals (cotton, soybean, lettuce, tomato)
all warm season turfgrasses
Rhizoctonia root rot / Large Patch of Turf geo
worldwide
Rhizoctonia root rot / Large Patch of Turf symptoms
Turf - circular patches of affected plants develop during spring / fall when grasses enter /exit dormancy period. Recently affected foliage may appear orange. Water-soaked or reddish brown lesions found on leaf sheaths (foliage dies back from this point)
Other plants - reddish-brown, sunken lesions
Rhizoctonia root rot / Large Patch of Turf signs
in wet weather, white cobwebby fungal growth, likely found on lower parts of plant
Distinguishable by right-angle branching
Rhizoctonia root rot / Large Patch of Turf favorable conditions
48 hours continuous moisture
Thatch temps between 50 - 70° F
Rhizoctonia root rot / Large Patch of Turf management
Control moisture -> soil drainage, air circulation, reduce excess shade
Mowing height (turf) -> with zoyziagrass, 1.5 inches decreases disease compared to 0.5 inch
Thyphula
Snow molds of turfgrasses
Agaricomycotina
characterized for having spores on lining of surfaces of small tubes or pores
Southern Stem Blight / white mold causal organism
Aethalium (Sclerotium) rolfsii
Sclerotium (-tia)
survival structure of Aethalium (Sclerotium) rolfsii [Southern Stem Blight / white mold]
golden to dark brown / black as they develop
Southern Stem Blight / white mold host range
more than 500 plant species
- tomato
- peanut
- apple
- many woody ornamentals and herbaceous annuals
Southern Stem Blight / white mold geo
Worldwide, but predominant in warmer climates
Southern Stem Blight / white mold symptoms
Begins as water-soaked lesion near soil line
Lesions expand to girdle stem
Plants wilt and die rapidly
Southern Stem Blight / white mold signs
White mat of mycelium develops at lesion… spreads across soil surface.
Round mycelial bodies begin to form
Seed-size structures are sclerotia -> darken to near black
Southern Stem Blight / white mold favorable conditions
Monocyclic
wide temp range (46 - 104° F), optimal = 81 - 95° F, high humidity favors hyphal growth
fluctuating moisture promotes sclerotial germination and rapid plant death, more sclerotia produced in 5 - 7 days
DOES NOT HAVE SPORES - mammals spread this disease. Will spread through soil but not far
Southern Stem Blight / white mold management
Keep fungus out of production area
Crop rotation to non-host (ie. grass)
Prompt removal of infected plants
Soil solarization - clear plastic, direct sun, 4 - 8 weeks
Fungicide (must be at base of plant)
Heterobasidion annosus (Fomes annosum)
Root and butt rot of conifers
Rotting fungi
Characterized by spores borne radiating gills, lots of mycorrhizal fungi
Armillaria mellea
Root rot of forest and fruit trees, esp oak.
Has edible fruiting body
Pleurotus spp
white rots of hardwoods
Pholiota spp
brown rots of hardwoods
Agaricus bisporus
Common edible mushroom in grocery store
Conks
“mushroom-like” structure on trees and woody structures. Monocyclic
basidiospores INSIDE conks… fall from structures, picked up by wind. Enters through wounds on trees / host.
Kills trees due to inner rotting
Mushrooms
Basidiospores on gills
Create fairy rings - usually presence of tree stump / wood in soil or old, buried roots
Dry rots
break down cellulose
Wet rots
Whitish fungal growth
fungi draw water to them
Stain fungi
Discolors wood - pink, blue, green, orange
Mycorrhizae
Root infectors, beneficial - helps plants absorb minerals (increase root surface area)
Three types of mycorrhizae
Ectomycorrhizae - external to root
Endomycorrhizae - internal to root
Ericoid mycorrhizae - intermediate
