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114 Cards in this Set

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What 4 points should you keep in mind when classifying diseases?
1)-some diseases may not readily fit into any of the groups presented
-merely emphasises the fact that classification is an artificial process
-in order to accommodate all diseases more readily, some groups might be split or new groups added

2)-some diseases may fit more than one group, again illustrating how artificial classification is

3)-some diseases may fit into one or anothe group according to environment conditions
-predisposition of the host by weather favourable to the pathogen may result in more severe symptoms

4)-some groups are not only based on symptoms, but also on parasite taxonomy
-in several cases, members o particular taxa of fungi all induce similar symptoms on the host
List the 17 groups of diseases
1-Damping off and Seedling Blights
2-Root and Foot Rots
3-Vascular Wilts
4-Wood Rots
5-Downy Mildews
6-Powdery Mildews
7-Rusts
8-Smuts
9-Miscellaneous Head Troubles
10-Blights
11-Stem Rots and Basal Stem Cankers
12-Snow Moulds
13-Leaf Spot and Anthracnoses
14-Galls and Malformations
15-Scabs and Cankers
16-Yellows and Mosaics
17-Post Harvest Diseases
How would you recognize Damping off and Seedling Blights?
-damping off involves rapid necrosis of the stem base or upper part of the tap root, causing the emerging seedling to fall over and die
-seedling blights affect slightly older plants and involve foliar discoloration and plant death
-most of these diseases are caused by soil borne fungi, but sometimes environmental factors lik high soil surface temperatures may be the cause
How would you recognize Root and Foot Rots?
-similar to seedling blights except that they affect the roots (root rot) or stem bases (foot rot) of more mature lpants
-caused by soild borne organisms, mostly fungi, and involve a progressive decay of the root system leading to various above ground symptoms
How would you recognize Vascular Wilts?
-typically caused by fungi or bacteria that penetrate the host through wounds and then concetrate their activity within the vascular tissue
-most wilts are soil borne
-decay and occlusion of the vascular tissue results in foliar discoloratoin, wilting and death
How would you recognize Wood Rots?
-diseases of the woody parts of trees in which progressive decomposition of the cellulose, linin or both occur, resultin in weakening and discoloration
-most wood rots are caused by higher basidiomycete fungi
How would you recognize Downey Mildews?
-caused by one family of obligate parasitic fungi (Family Peronosporaceae)
-symptoms invove a WHITISH or GREYISH or LIGHT BROWN DOWNY growth on aerial plant parts
-when the leaves are affedted, the growth is often on the lower surface and chlorosis is evedent on the upper surface
How would you recognize Powdery Mildews?
-caused by one order of obligate parasitic fungi (Order Erysiphales)
-aerial plant structures are covered by a powdery WHITISH growth that eventually becomes speckled with BROWN or BLACK pinhead sized bodies
-disease flourishes under relatively dry conditions
How would you recognize Rusts?
-caused by one order of fungi (Order Uredinales)
-aerial plant parts are affected and the group takes its name from the rusty RED or BROWN spore PUSTULES that develop on the surfaces of infected structures
How would you recognize Miscellaneous Head Toubles?
-heterogeneous groupod diseases applying to the cereals, in which the inflorescence is often referred to as the head
-discoloration or malformation of the head occurs -OR- parts of it are replaced by structures of the parasitic organism
-most prominent example is ERGOT
How would you recognize Smuts?
-related to the rusts, the smuts are caused by the fungal order Ustilaginales
-characteristic symptoms are the replacement of aerial plant parts by SOOTY BLACK SPORE MASSES
-often he spore masses replace parts of the inflorescence, especially with cereal smut diseases
-galls may sometimes develope too
How would you recognize Blights?
-term blight properly applies to rapidly spreading and extensive necrosis of plant foliage due to generalized invasion by a pathogen
-word 'blight' is often used in the names of diseases more appropriately classified as leaf spot/limited lesion diseases
-blights are mostly caused by fungi and bacteria
How would you recognize Stem Rots and Basal Stem Cankers?
-stem rots and blights in which infection is concentrated in the host stem kills the stem and will cause the death of the attached leaves, even though the leaves themselves may not be infected
-basal stem cankers involve a PINCHING OFF of the base of a mature plant due to infection
-the difference from a foot rot is that infection is of aerial origin, whereas a foot rot is caused by a soil borne pathogen
How would you recognize Snow Moulds?
-are a unique group of blight diseases caused b psychrophilic fungi
-occur only in cold, temperate latitudes
-the fungi are active under permanent snow cover in the winter, killing the crowns and upper tap roots of biennial and perennial plants
-when snow melt occurs in the spring, a mat of fungal mycelium (mould) is evident on the soild surface and around dead tissues
How would you recognize Leaf Spot (Limited Lesion) Diseases and Anthracnoses?
-invasion of the host plant structures reults in a restricited necrotic lesion (leaf or other) that may have a characteristic colour or shape
-many viruses that induce other symptoms on their main hosts produce necrotic spots when inoculated on a so called local lesion host; the local lesion host can be used to determine virus concentrations
How would you recognize Galls and Malformations?
-these diseases are characerised by swelling, leaf rolling or some other malformation of the plant structure
How would you recognize Scabs and Cankers?
-characterised by a mixed reaction in the host tissue; some overgrowth is combined with some cell necrosis
-the result is a slightly raised pustule on, or a malformation of the plant structure, coupled with discoloration due to cell death
How would you recognize Yellows and Mosaics?
-caused by phytoplasms, viruses or non parasitic factors
-above ground plant structures, expecially leaves, turn wholly or partly yellow or develop some other abnormal colour, usually in a characteristic pattern
How would you recognize Post Harvest Disease?
-sometimes called 'market' diseases or 'storage' diseases
-affect fleshy plant strucutures after harvest
-involves a soft rotting of the tissues
-caused by fungi, bacteria, or non parasitic agents.
What medium can fungi grow in?
-solid
-semi solid
-liquid
What diseases are caused by the Class Plasmodiophoromycetes (Kingdom Protozoa)?
Club Root of Crucifers (263-266)
*Pathogen: Plasmodiophora brassicae
-club root is a serious disease of veg crucifers (Fam Crucifae, eg:cabbage, turnip, and mustard)
-extensive swellings develop on infected roots and taproot developement is suppressed
-galls are orinigally firm and white, but become soft and greyish as they mature and later decay
-galls are a result of HYPERTROPHY and have an enlarged nucleus and nucleolus
-infected host cells contain either PLASMODIA or highly GRANULAR RESTING SPORES
What diseases are caused by the Class Oomycetes (Kingdom Chromista)?
1) Late Blight of Potato and Tomatoe
*Pathogen: Phytophthora infestans
-largely responsible for the Irish 'potato famine'
-infections onleaves and stems first appear as water soaked lesions that rapidly expand and may have a PALE GREEN HALO
-infection often occurs near the leaf margins or midvein
-a WHITE, COTTONY FUNGAL GROWTH may develop on the underside of the affected leaves
-symptoms are limited in dry weather, wet weather result in rotting of the entire plant, which gives off distinctive odour
-disease also causes a rot of tubers both in the ground and in storage
-asexual reproduction is by means of sporangia
-a heterothallic fungus and therefore sexual reproduction will only take place if 2 different strains of the fungus are present together

2)Phytophthora Rot of Soybean
*Pathogen: Phytophthora sojae
-symptoms on more mature plants may include yellowing, wilting or stunting, and death of plants
-on of the diagnostic symptoms of phytophthora stem rot s a brown lesion that appears on the stem at the soil line and progresses up the stem
-affected plants have little or no roots

3)Pythium spp as plant pathogens
*Pathogens: P. debaryanum (damping off), P. arrhenomanes (browing root rot of wheat)
-cause a variety of soild borne diseases (damping off, root rot)
-sporangia are pear shaped to spherical and sometimes difficult to distinguish from oogonia
-sexual reproduction involves fusion of one or more antheridia with an oogonium to form a thick walled oospore containing a distinct oil globule
-symptoms of Pythium include: leaf yellowing, necrosis, stunting and tip discoloration of he crown roots

4) Blister Blight or White Rust and Staghead of Crucifers
*Pathogen: Albugo candida
-common pathogen of rapeseed
-has local and systemic infection
-local infection is characterized by the creamy white subepidermal pustules of asexual sporangia (White Rust), developes in the leaf undersurface
-shows the GREEN ISLAND EFFECT in the upper side of the leaf
-if the infection becomes systemic, inflorescences become swollen and malformed and are referred to as STAGHEADS
-pustules of sporangia may also form on the stagheads, oospores are embedded in the swollen tissues

5) Downey Mildew of Crucifers
*Pathogen: Peronospora parasitica
-severe under moist climatic conditions
-induce rather similar symptoms on aerial portions of the plant
-have large/lobular haustoria
-think about Downey Mildew of Grapes
What causes Late Blight of Potato and Tomato?
Pathogen: Phytophthora infestans (Class Oomycetes [Kingdom Chromista])

-largely responsible for the Irish 'potato famine'
-infections onleaves and stems first appear as water soaked lesions that rapidly expand and may have a PALE GREEN HALO
-infection often occurs near the leaf margins or midvein
-a WHITE, COTTONY FUNGAL GROWTH may develop on the underside of the affected leaves
-symptoms are limited in dry weather, wet weather result in rotting of the entire plant, which gives off distinctive odour
-disease also causes a rot of tubers both in the ground and in storage
-asexual reproduction is by means of sporangia
-a heterothallic fungus and therefore sexual reproduction will only take place if 2 different strains of the fungus are present together
What causes Phytophthora Rot of Soybean?
Pathogen: Phytophthora sojae (Class Oomycetes [Kingdom Chromista])

-symptoms on more mature plants may include yellowing, wilting or stunting, and death of plants
-on of the diagnostic symptoms of phytophthora stem rot s a brown lesion that appears on the stem at the soil line and progresses up the stem
-affected plants have little or no roots
What causes Pythium spp as plant pathogens?
Pathogens: P. debaryanum (damping off), P. arrhenomanes (browing root rot of wheat)(Class Oomycetes [Kingdom Chromista])

-cause a variety of soild borne diseases (damping off, root rot)
-sporangia are pear shaped to spherical and sometimes difficult to distinguish from oogonia
-sexual reproduction involves fusion of one or more antheridia with an oogonium to form a thick walled oospore containing a distinct oil globule
-symptoms of Pythium include: leaf yellowing, necrosis, stunting and tip discoloration of he crown roots
What causes Blister Blight or White Rust and Staghead?
Pathogen: Albugo candida (Class Oomycetes [Kingdom Chromista])

-common pathogen of rapeseed
-has local and systemic infection
-local infection is characterized by the creamy white subepidermal pustules of asexual sporangia (White Rust), developes in the leaf undersurface
-shows the GREEN ISLAND EFFECT in the upper side of the leaf
-if the infection becomes systemic, inflorescences become swollen and malformed and are referred to as STAGHEADS
-pustules of sporangia may also form on the stagheads, oospores are embedded in the swollen tissues
What causes Downey Mildew of Crucifers?
Pathogen: Peronospora parasitica (Class Oomycetes [Kingdom Chromista])

-severe under moist climatic conditions
-induce rather similar symptoms on aerial portions of the plant
-have large/lobular haustoria
-think about Downey Mildew of Grapes
Draw and label Plasmodiophora brassicae. Disease and Host?
Disease: Club root
Host: Crucifer

Did you get:
-plasmodia infected cells
-enlarged nucleus due to hypertrophy
-infected host cells containing granular resting spores
-healthy host cells
Draw and label Phytophthora infestans infection. Disease and Host?
Disease: Late Blight
Host: Potatoe

Did you get:
*********Leaf*****************
-whitish mold present in necrotic areas
-necrotic tissue
-leaf folding, showing wilts
-necrosis radiating from the inside to outside
-healthy tissue

***********Tuber**************
-infection occuring from the OUTSIDE->IN
Draw and label Albugo candida. Disease and Host?
Disease: Blister Blight
Host: Brassica spp

Did you get:
***********Oospores*************
-host cell
-oospore with spiny cell wall, does NOT lie inside the cell, lies inbetween them

******Sporangial Pustule******
-intercellular hypae (green)
-intracellular haustoria
-subepidermal sporangial pustule
-sporangiophore
-sporangia in chains

************Leaf**************
-pustule (creamy color)
-green island effect

//////////////////////////////
Disease: Staghead
Host: Mustard

Did you get:
-pustule of sporangia
-staghead (swollen and malformed; may contain oospores; region is brown)
Draw and label Peronospora parasitica. Disease and Host?
Disease: Downy Mildew
Host: Crucifer

Did you get:
-infected host cells
-lobular haustoria (lack finger like projections; pinkish color)
-uninfected cells
What causes Potato Wart?
Pathogen: Synchytrium endobioticum (Chytridiomycetes)

-causes hypertrophy and hyperplasia of the surface cell layers of the infected potato tubers resulting in unsightly galls and malformation making the tubers unmarketable
What causes Crown Wart of Alfalfa?
Pathogen: Urophlyctis alfalfae (Chytridiomycetes)

-infected young crown buds enlarge (hypertrophy/hyperplasia) to form galls, most of which originate at or slightly below the soil surface
-galls are white when young and turn grey to brown as they dry and decay in midsummer
-sporangia are thick walled, light brown to golden brown, and hemispherical
What causes Bread Mould?
Pathogen: Rhizopus spp (Zygomycetes)

-reproduces asexually by producing sporangia that contain non motile spores
-reproduces sexually by producing zygospores that result from the fusion of 2 similar gametangia
-3 types of hyphae:
--1)arial sporangiophore with collumellae
--2)surface stolons
--3)root like rhizoids
What are some characteristics to the Zygomycetes?
-no zoospores
-asexual apores made in sporangium
-sexual zygospores produced by fusion of morphologically similar gametangia
-well developed hyphae, usually aseptate
What are some characteristics to the Subphylum Ascomycetes?
-have an asexual conidial state (ANAMORPH) that is more abundant or more important in the epidemiology of the disease than the sexual state (TELEOMORPH)
What causes Plum Pockets?
What causes Peach Leaf Curl?
Pathogen: Taphrina pruni (Ascomycetse)
-cause one or more kinds of malformations of above ground plant parts

///////////////////////////////
Pathogen: Taphrina deformans
What causes Powdery Mildew of Gramineae?

What causes Powdery Mildew of Peas?
Pathogen: Blumeria graminis (Ascomycetes/Deuteromycetes)
/////////////////////////////////
Pathogen: Erysiphe pisi & Erysiphe polygoni (Ascomycetes/Deuteromycetes)

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
-powdery mildew fungi (Order Erysiphales) produce naked chains of conidia for a sexual reproduction, while for sexual reproduction they produce asci and ascospores enclosed within a type of ascocarp (CLEISTOTHECIUM)
-genera of powdery mildew fungi are distinguished on by their cleistothecia (# of asci in cleistothecium; # and type of appendages on the outside
How did we prepare Powdery Mildew Cleistothecia for observation?
-took leaves with cleistothecia and scraped it onto a microscope slide and mounted it in cotton blue
-let sit for 20-30min to soften it up
-crushed it and saw the asci and ascospores ooze out
-also saw appendages
What causes Blue Mould Rot of Fruit?
Pathogen: Penicillium spp (Deuteromycetes)

-have scattered asci in cleistothecium
-asexual structures include: unicellular conidia in chains; conidiophores; phialides
How do you do a tape mount slide?
-dab the tape in the colony
-dab the tape in ethanol
-dab the tabe in cotton blue
-have tape, spore side up
-cover with coverslip
-have at it
Draw Rhizopus spp. Disease and Host?
Disease: Bread Mould/Rhizopus Soft Rot
Host: Bread

Did you get:
-sporangiospores (black; granular)
-columella (balloon like with spores)
-sporangiophore (brownish and transparent)
-sporangium (includes sporangiospores and columella)
-stolon (surface runner; brownish and transparent; bears sporangiophore and rhizoids)
-rhizoids (branches quite often)
Draw Taphrina pruni. Disease and Host?
Disease: Plum pockets
Host: Plum

Did you get:
-ascus (greenish blue; rectangular shape)
-ascospores (stained red; #'s vary widely per ascus)
-mycelial stroma
-host epidermal cells
-host tissue cells
Draw Erysiphe pisi. Disease and Host?
Disease: Powdery Mildew
Host: Pea

Did you get:
******Crushed Cleistothecium*****
-ascus (transparent)
-ascospore (8/ascus; yellowish)
-appendages (finger like projections; blue color; random)

*********X-Sec****************
-conidia in chains
-conidiophore
Draw Penicillium spp. Disease and Host?
Disease: Blue mould rot of fruit
Host: bread and fruit

Did you get:
*******Asexual structures*********
-conidia (in chains)
-phialide (no color differentiation)
-conidiophore (section before penicillus)
-penicillus (includes: stalk bearing phialide, phialide and conidia)

****X sec of Cleistothecium****
-ascospores (free floating; reddish orand; cluster; encased in ascus)
-cleistothecial cell wall (brownish red color)
-appendages (blue; bears a dark spot at apical end)
What are some characteristics to Pyrenomycetes?
-ascomycetes with perithecia
What causes Ergot of Cereals and Grasses?
Pathogen: Claviceps purpurea [Anamorph: Sphacelia sp] (Pyrenomycetes)

-causes head disease of many graminae spp
-ergot bodies are poisonous
-fungal ascospores land and germinate on mature flowers, infecting the plant through the stigma
-the ovarian tissues are eventually replaced by a purplish or black sclerotium
-initial mycelial mat that forms in the ovary has many folds along its surface and produces conidia on its surface in sweet smelling nectar, which attracts insects that will spread them to other plants
-funal tissue eventually melanizes and hardens (SCLEROTIA)
What causes Dutch Elm Disease?
Pathogen: Ophiostoma ulni

-vascular wilt disease
-read bio 204 stuff if you're interested... shit
What are some characterisitics to Loculoascomycetes?
-ascomyctes with Ascostroma (pseudothecium is bitunicate)
What causes Apple Scab?
Pathogen: Venturia inaequalis [Anamorph: Spilocaea pomi] (Loculoascomycetes)

-stroma is a mass of undifferentiated tissue resembling parenchym
-stroma forms on the surface of infected leaves or fruit and the asci in the locules produce 2 celled ascospores
-conidial state is also produced on the surface of the stroma
What causes Blackleg of Rapeseed and other Crucifers?
Pathogen: Leptosphaeria maculans [Phoma lingam] (Loculoascomycetes)

-consists of greyish white lesions on the leaves, pods, stems and especially stem bases
-the lesions are usually speckled with minute black pycnidia of the fungus
-pinkish spore masses ooze out of the pycnidia and are dispersed by rain splash
-basal stem lesions may develop into sever basal stem cankers that can kill young plants and cause serious stem break, lodging and premature ripening
What causes Sclerotinia Stem/Soft Rot and White Mould of Various Hosts?
Pathogen: Sclerotinia sclerotiorum [Anamorph: Sclerotium sp] (Discomycetes)

-produces a cup shaped ascocarp called an APOTHECIUM
-does not produce an asexual fruiting stage
-apothecia develop from sclerotia
-sclerotia remain formant for long periods of time, requiring a specific range of temperature and moisture conditions (10 consecutive days of cool, humid weather) before they will germinate and produce apothecia
-invades vascular systems causing premature ripening, resulting i shrivelled seeds and sensecing leaves
Draw and label Claviceps purpurea. Disease and Host?
Disease: Ergot of Cereals and Grasses
Host: Cereals and grasses

Did you get:
**Long x-sec of sphaeridium****
-stroma (pinkish color)
-perithecium (darker pink than stroma; ostiole)
-ostiole
-stalk

******Perithicium*************
-ostiole
-ascospore (filamentous; multicellular; stained red)
-2 visible layers
-asci
Draw and label Venturia inaequalis. Disease and Host?

Anamorph?
Disease: Apple Scab
Host: Apple fruit or leaves

Did you get:
*********x-sec of leaf*******
-asci (transparent; stained red)
-pseudothecium (1 wall, no differentiation)
-ostiole
-ascospores (2 celled; stained red)
-internal cells of pseudothecium
-stained blue

//////////////////////////////
Anamorph: Spilocea pomi

Did you get:
*******Leaf x-sec*************
-conidia (red)
-conidiophore (red)
-thin cuticle layer
-fungal stroma (granular; purpulish color)
-epidermal layer (blue)
-mesophyll cell
Draw and label Sclerotinia sclerotiorum. Disease and Host?
Disease: Sclerotia stem/soft rot
Host: Canola, mustard, pea, chickpea, sunflower

Did you get:
***Sclerotinia apothecium******
-hymenium layer
-apothecium
-ascus (8 ascospores)
-ascospore (oval shape; yellowish color)

******Sclerotinia apothecia****
-sclerotium (black mass bearing apothecia)
-apothecium stalk
-abothecium cap
-paraphysis
What causes Botryis stem and pod rot of chickpea and lentil; Grey mould of various plants?
Pathogen: Botrytis cinerea [Teleomorph: Botryotinia fuckeliana] (anamorphic deut/ascomycete)

-has a wide host range
-on chickpea and lentil, seed borne infections can result in seed rot and seedling blight
-later infectoins, causing stem and pod rot are favoured bymoist conditios and are typically more severe under a heavy crop canopy
-infected pods do not fill properly, or contain infected seed that is discoloued and shrivelled
-clouds of spores are dispersed into the ai as infected areas are harvested
-tips of the long, dark, branche conidiophores have a small, rounded swelling upon which clusters of conidia are produced

**Lab 7**
What causes common root rot of wheat and spot blotch?
Pathogen: Cochliobolus sativus [Anamorph: Bipolaris sorokiniana] (anamorphic deut/ascomycete)

-common root rot is caused primarily by Cochliobolus sativus, and to a lesser extent, by species of Fusarium
-sexual state is a loculascomycete, rarely found under natural conditions and has only been ID'd in areas of africa
-primary infections form on the host roots mainy from soil borne conidia and mycelium of the fungus, they result in seedling blight , root rot and prematurity blight
-lesions occur on the subcrown internode
-secondary infection of plants by air borne conidia of C. sativus may occur if conditions are favourable
-plants are most susceptible when the inflorescence is about 3/4 emerged

Anamorph: Bipolaris sorokiniana
-conidia are darkly pigmented, large (up to 100um long), multicellular (5 to 9 cells) and fusiform
-produced on conidiophores in an apical position but through sympodial growth of the conidiophore they appear to be produced both apically and laterally
-conidiophores grow on the surface of the substrate, arising from vegetative hyphae
-conidia exhibit bipolar germination (germ tube from each end) hence the name Bipolaris
What causes Net Blotch of Barley?
Pathogen: Pyrenophora teres [Anamorph: Drechslera teres] (anamorphic deut/ascomycete)

-P. teres is a loculascomycete
-disease symptoms appear first as small bown spots, usually near the tip of the blade
-spots elongate and develope a transverse and longitudinal pattern of brown pigmentation
-a zone of chlorotic tissue is commonly found around the necrotic tissue
-net like lesions on presereved host leaves
What causes Tan Spot of Wheat?
Pathogen: Pyernophora tritici repentis [Anamorph: Drechslera tritici repentis] (anamorphic deut/ascomycete)

-tan spot is mainly a foliar disease of WHEAT, TRITICALE and several GRASSES, although rye and barley are occarionally affected
-first symptoms appear as small yellow brown spots that develop into irregular lens shaped, light brown lesions which may have yellow borders
-as the lesions merge, large areas of the leaves turn yellow and die
-necrosis often begins near the tip and advances toward the base of the leaf
-heavy sporulation may cause the centres of the lesions to darken
-has a pseudothecia
What causes Fusarium Root Rot and Head Blight of Cereals?
Pathogen: Fusarium graminearum/spp [Anamorph: Gibberella zeae] (anamorphic deut/ascomycete)

-F. graminearum is the dominant pathogen in NA
-fusarium spp complex is typically associated with cereals but it has been implicated in root rot and seedling blight
-head blight/scab by F. spp are evident by pinkening of the kernels, shrinkage, chalky white, and have a low kernel weight
-disease is characterised by premature bleaching of infected spikelets
-may have either macro/microconidia or both
-may have chalmydospores
What causes Fusarium wilts?
Pathogen: F. oxysporum & F. avenaceum (anamorphic deut/ascomycete)

-similar symptoms of wilting (leaf discoloration of the vascular tissue due to vascular occlusion(blockage))
What causes Dry Rot of Potatoes?
Pathogen: Fusarium spp (anamorphic deut/ascomycete)

-causes the inner flesh to disintegrate, but does not affect the skin in the same manner
-note the concentric rings of collapsed skin caused by the rot, and masses of mycelium produced on the suface of the decayed plant
Draw and label Botrytis cinera. Disease and Host?
Disease: Botrytis stem and pod rot
Host: Chickpea and lentil

Did you get:
-hypha (septate)
-septum
-conidiophore (plump; septate)
-conidia (opaque; looks like broccoli)

**Lab 7**
Draw and label Cochliobolus sativus. Disease and Host?
Disease: Common root rot of wheat and spot blotch
Host: Wheat

Did you get:
***Rykar mount of wheat root***
-stem
-lesions on the subcrown internode
-subcrown internode (region between attachment and secondary roots)
Draw and label Fusarium spp. Disease and Host?
Disease: blights, wilts and shit
Host:Cereals

Did you get:
-F. graminearum (no microconidia)
-F. culmorum (no microconidia)
-F. oxysporum (no microconidia or chlamydospores)

//////////////////////////////
Disease: Dry Rot of Potatoe

Did you get:
-white crust (mycelia)
-concentric rings of collapsed skin caused by the rot
What causes Black spot of canola?
Pathogen: Alternaria spp. (Deut/Basidiomycetes)

-responsible for several leaf spots and blights
-usually found on older, senescing tissues or on plants that are under stress
-most conspicuous symptoms are the black spots that appear on the stems and pods (itty bitty black spots)
-lesions may have concentric circular zones, alternating in colour, surrounded by a chlorotic halo
What causes Anthracnose?
Pathogen: Colletotrichum spp (Deuteromycetes with acervuli)

-mainly affect the foliar parts of plants
-initial infection sites have a water soaked appearance, which then develop into sunken lesions with pale centres and dark margins
-have acervuli (a cushion of conidiophores and conidia)
-initially subcuticle/epidermal
What causes Septoria/stagonospora leaf and glume blotch of wheat and grasses?
Pathogen: Septoria tritici and Stagonospora spp (Deuteromycetes with pycnidia/sporogonium)

-attack wheat world wide, inducing symptoms on leaves, leaf sheaths and glumes
-dark brown discolouration of the glumes and the golden brown to greyish rown lesions on leaves
-diseased leaves are speckled with minute black pycnidia
What causes Ascochyta blight of lentil and chickpea?
Pathogen: Ascochyta lentis/rabiei (Deuteromycetes with pycnidia/sporogonium)

-ascochyta blight is the most damaging disease of chickpea in Canada
-symptoms occur on aerial plant parts at any growth stage
-circular, necrotic lesions on leaflets and pods are a light tan or grey color and often have a discrete tan coloured margin
-centres of lesoins are speckeld with dark brown or black pycnidia, which may form in concentric rings
What causes Winter Crown Rot of Alfalfa/Snow Mould of Turf Grasses and Winter Cereals?
Pathogen: Coprinus psychromorbidus (Basidiomycete)

-several psychrophilic fungi cause snow mould of turf grasses
What causes White Heart Rot of Trees?
Pathogen: Phellinus igniarius (Basidiomycete)

-a common pathogen of aspen and other trees in SK
-basidiocarps of the fungus are woody, bracket like structures that develop on the trunk and branches of rees
-basidiospores have tiny holes on the underside
-gives wood a whitish appearance
What causes Armillaria Root Rot of Trees?
Pathogen: Armillaria mellea (Basidiomycete)

-white mycelial mats form between the bark and wood at the base of the tree and may extend upward for a few feet
Draw and label Alternaria spp. Disease and host?
Disease: Blck spot of canola
Host: canola

Did you get:
-hypha (septate)
-macroconidia (tapers off at one end)
-conidiophore (irregular septa intervals
Draw and label Colletotrichum lindemuthianum. Disease and Host?
Disease: Anthracnose
Host: Soybean

Did you get:
***Surface of Soybean stem*****
-conidia mass (a whitish ooze; imbedded in the setae for protection)
-stem hairs (white, thick and long)
-acervulus (a black mass; on it are stroma from which setae arise)
-setae (black,spiny projections; projects from stroma
-bean stem
Draw and label Septoria tritici and Stagnospora nodurum. Disease and Host?
Disease: Septoria leaf and glume blotch of wheat and grasses
Host: Wheat and grasses

Did you get:
******Pycnidium***************
-crushed pycnidium
-hyphae on pycnidium
-conidia (long, narrow, curved, threadlike; composed of several cells
Draw and label Ascochyta rabiei. Disease and Host?
Disease: Ascochyta blight of lentil and chickpea
Host: Chickpea

Did you get:
-crushed pycnidium (brown, rough texture; evident striations)
-ostiole
-conidia (bean shaped; usually 2 celled; stained purple)
Draw and label Coprinus psychromorbidus. Disease and Host?
Disease: Winter crown rot of alfalfa/ Snow mould of turf grasses and winter cereals
Host: alfalfa, grasses, cereals

Did you get:
-lamella
-central stipe
-hymenium layer (basidia; sterigmata; basidiospore [4/basidium])
What causes Bunts or Stinking Smuts of Wheat?
Pathogen: Tilletia tritici (Basidiomycetes - Ustilaginales, smuts)

-original host tissue inside of the smutted kernels has been replaced by a mass of sooty spores
-bunts cause less destruction of the kernels (pericarp remains intact) than overed smut of barley
-has a fishy smell
-germinated telopspore produces promycelium (basidium) with primary sporidia forming at the terminal end
-primary sporidia will fuse in paris by a lateral tube to give them an H appearance
-primary sporidia then germinate to produce dikaryotic secondary sporidia
What causes Loose Smut of Barley and Wheat?
Pathogen: Ustilago nuda (barley); Ustilago tritici (wheat) (Basidiomycetes - Ustilaginales, smuts)

-produces masses of black fungal spores in place of the grains
-these plants mature about 10 days earlier than healthy plants, so that the spores are spread to health plants at about the time they are reaching anthesis
-spores germinate on the ovaries of healthy plants and penetrate and produce a small amount of resting mycelium in the embryo of the developing seed
-mycelium remains dormant as the seed ripens and does not begin to grow until the seed germinates the following spring
-the fungus spreads in the plant as it grows, this may cause some reduction in % emergence of seedlings, but enerally, the disaes has no pronounced effect on the plant until the time of flowering
-spore wall ornamented
What causes Covered Smut of Barley?
Pathogen: Ustilago hordei (Basidiomycetes - Ustilaginales, smuts)

-has a different life cycle from that of U. nuda
-looks different too
What causes Stem Rust of Cereals?
Pathogen: Puccinia graminis (Basidiomycetes - Uredinales, rusts)

-causes stem rust or black stem rust of what and many other grasses
-heteroecious rust (barberry and cereals)
-pycnia = spermogonia
-you know this one... bio 204
What causes Leaf Rust of Wheat and other Cereals?
Pathogen: Puccinia recondita (Basidiomycetes - Uredinales, rusts)

-spermagonia and aecia stage occur on meadow rue
-sure it's not that important
What causes Flax Rust?
Pathogen: Melampsora lini (Basidiomycetes - Uredinales, rusts)

-an autoecious rust (all 5 spore stages occur on the flax plant)
What causes Cedar apple Rust of Saskatoon?
Pathogen: Gymnosporangium corniculans (Basidiomycetes - Uredinales, rusts)

-heterocious (on Pomoideae and Juniperus)
-uredia are usually not present in this genus of rust fungi
What are some defining characterisitics to the Class Hemibasidiomycetes?
-includes: smuts & bunts(Order Ustilaginales), and rusts (Order Uredinales)
-extended dikaryophase
-no basidiocarp
-septate basidium
What are some defining characteristis to the Order Ustilaginales?
-obligate parasite in nature (yeast like in culture)
-infections are usually systemic
-teliospores replace host tissue
What's the main differences between Bunts, Loose smuts and Covered smuts?
-Bunts affect wheat
-Loose Smuts affect wheat or barley
-Covered Smuts affect barley
What's the difference between Loose smuts and Covered smuts?
Loose smuts
-internal
-cause more extensive damage
-everything but rachis (middle) is replaced

Covered smuts
-surface
-teliospores replace internal structures of seed
-outer parts of seed remain intact
How does Loose smut infection occur?
-internal
-mycelium dormant until spring
-systemic infection causes premature heading
-teliospores spread by wind (germinate within healthy flowers; produce promycelium/basidium)
-uninucleate hypha arises from basidium (becomes dikaryotic by conjugation)
-dikaryotic hyphae capable of infection
How does Covered smut infection occur?
-surface
-teliospores dormant until seed germinates
-teleiospores produce septate basidium that buds to produce haploid sporidia
-sporidia fuse and produce dikaryotic hyphae capable of infection
-infect young seedlings
-systemic infection until heading
How does Bunt infection occur?
-by Tilletia spp.
-teliospores produce basidium
-basidium produces primary sporidia (slender basidiospores at tip of basidium)
-primary sporidia fuse 'H' structure
-secondary sporidium produces dikaryotic hyphae capable of infection
-systemic infection until heading
What are some defining characteristics to the Order Uredinales?
-AKA Rusts
-obligate parasites
-infections localized
-autoecious or heteroecious
-microcyclic (few spore types) or macrocyclic (many spore types)
Draw and label Tilletia tritici. Disease and Host?
Disease: Bunts or Stinking smuts of wheat
Host: Wheat

Did you get:
-teliospore
-promycelium/basidium
-immature primary sporidia
-point of fusion
-secondary sporidium
-mature secondary sporidium
-dikaryotic hyphae
Draw and label Ustilago tritici. Disease and Host?
Disease: Loose smut of Barly and wheat
Host: Wheat

Did you get:
-brown spore
-promycelium/basidium
-basidiospore
-hyphae
-fused hyphae
-dikaryotic mycelium
Draw and label Puccinia graminis. Disease and Host?
Disease: Stem rusts of cereals
Host:cereals, grasses and barberry

Did you get:
-epidermal cell
-pycnium/spermogonium
-receptive hyphae
-mesodermal cells
-aecium
-peridium
-aeciospores

-uredial infections (beanshaped, aseptate; multicelled pedicel)
-telial infections (2 celled; single celled pedicel)
Draw and label Gymnosporangium corniculans. Disease and Host?
Disease: Cedar apple rust
Host: Juniperus scopulurum

Did you get:
-healthy branches
-telial horn (yellow; jelly texture)
-gall (dark brown; gruesome)
What causes Blackleg of Potatoes/Soft Rot of Vegetables?
Pathogen: Erwinia carotovora (Bacteria)

-black soft rot of the stem base
-frequently followed by death of the plant and decay of tubers which characteristically starts from the stem end
What causes Common Scab of Potatoes and other vegetables?
Pathogen: Streptomyces scabies (Bacteria)

-sperficial infection
-scab = cell division and death = raised pustule
What causes Halo blight of bean and oats?
Pathogen: Pseudomonas syringae (Bacteria)

-brown inside surrounded by a yellow region
What causes Fire blight of apple?
Pathogen: Erwinia amylovora (Bacteria)

-bacterial ooze apparent
-leaves are thin except for vascular areas
What causes Crown Gall?
Pathogen: Agrobacterium tumefaciens (Bacteria)

-incites gall formation by hypertrophy and hyperplasia
What causes Bacterial Ring Rot of Potatoes?
Pathogen: Clavibacter michiganense (Bacteria)

-occurs in a ring internal of the tuber
-accompanied by a milky juice and a foul odour
What causes Bacterial wilt of alfalfa?
Pathogen: Clavibacter michiganensis (Bacteria)

-curled leaf
-yellow stem
-f'd up root structure
What causes common blight on bean?
Pathogen: Xanthomona campestris (Bacteria)

-golden color with dark spots
What causes Aster Yellow Disease of Various Hosts?
Pathogen: Aster yellows phytoplasmas

Symptoms include:
-witches broom on carrot
-phyloidy on flax (leafening of flowers)
-virescence on Canola (greening)
-Chlorosis on Delphinim (yellowing)
-Etiolation of Buckwheat (elongation of flowering structure of stem)
What causes Tobacco Mosaic Disease?
Pathogen: Tobacco Mosaic Virus (virus)

-chlorotic mottling
-leaf distortion
-flower discoloration
-stunting
-wide host range
-mosaicy lines
What causes Barly Yellow Dwarf Disease?
Pathogen: Barley yellow dwarf virus (virus)

-causes yellowing of grassy tips
What causes Leaf roll of potatoe?
Pathogen: Potato leaf roll virus (virus)

-curled leaf
-tuber slices show 'net necrosis'
What causes Root Knot Nematodes?
Pathogen: Meloidogyne spp (nematodes)

-males are stick like
-females are pear like
-saliva induce hypertrophy/plasia resulting in galls
What causes Sugar Beet Nematodes?
Pathogen: Heterodera schachtii (virus)

-males are worm like
-females are lemon shaped
List 4 Non-Parasitic Disease
1) Nutrient Deficiencies of Plants

2) Heat and Frost Canker

3) Blast of Cereals
-hot and dry during flowering

4)Herbicide Damage
Draw and label Agrobacterium tumefaciens. Disease and Host?
Disease: Crown gall
Host: Wide variety

Did you get:
-healthy tisse
-gall area (hypertrophy vs. hyperplasia)
Draw and label Aster yellows phytoplasma. Disease and Host?
Disease: Aster Yellow Disease
Host: Various Host

Did you get:
-witches broom on carrot
-phloidy on flax (leafening of flowers)
-virescence of canola (greening of flower)
-chlorosis on delphinim (yellowing of flower)
-etiolation of buckwheat (elongation of flower stem)
Draw and label Meloidogyne spp. Disease and Host?
Disease: Root Knot Nematodes
Host: various roots

Did you get:
-infected cells
-healthy cells
-female nematode (pear shaped)
-egg sac