Bio 345 Lab Final

Front 1

What 4 points should you keep in mind when classifying diseases?

Back 1

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

Front 2

List the 17 groups of diseases

Back 2

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

Front 3

How would you recognize Damping off and Seedling Blights?

Back 3

-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

Front 4

How would you recognize Root and Foot Rots?

Back 4

-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

Front 5

How would you recognize Vascular Wilts?

Back 5

-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

Front 6

How would you recognize Wood Rots?

Back 6

-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

Front 7

How would you recognize Downey Mildews?

Back 7

-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

Front 8

How would you recognize Powdery Mildews?

Back 8

-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

Front 9

How would you recognize Rusts?

Back 9

-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

Front 10

How would you recognize Miscellaneous Head Toubles?

Back 10

-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

Front 11

How would you recognize Smuts?

Back 11

-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

Front 12

How would you recognize Blights?

Back 12

-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

Front 13

How would you recognize Stem Rots and Basal Stem Cankers?

Back 13

-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

Front 14

How would you recognize Snow Moulds?

Back 14

-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

Front 15

How would you recognize Leaf Spot (Limited Lesion) Diseases and Anthracnoses?

Back 15

-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

Front 16

How would you recognize Galls and Malformations?

Back 16

-these diseases are characerised by swelling, leaf rolling or some other malformation of the plant structure

Front 17

How would you recognize Scabs and Cankers?

Back 17

-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

Front 18

How would you recognize Yellows and Mosaics?

Back 18

-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

Front 19

How would you recognize Post Harvest Disease?

Back 19

-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.

Front 20

What medium can fungi grow in?

Back 20

-solid
-semi solid
-liquid

Front 21

What diseases are caused by the Class Plasmodiophoromycetes (Kingdom Protozoa)?

Back 21

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

Front 22

What diseases are caused by the Class Oomycetes (Kingdom Chromista)?

Back 22

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

Front 23

What causes Late Blight of Potato and Tomato?

Back 23

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

Front 24

What causes Phytophthora Rot of Soybean?

Back 24

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

Front 25

What causes Pythium spp as plant pathogens?

Back 25

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

Front 26

What causes Blister Blight or White Rust and Staghead?

Back 26

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

Front 27

What causes Downey Mildew of Crucifers?

Back 27

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

Front 28

Draw and label Plasmodiophora brassicae. Disease and Host?

Back 28

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

Front 29

Draw and label Phytophthora infestans infection. Disease and Host?

Back 29

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

Front 30

Draw and label Albugo candida. Disease and Host?

Back 30

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)

Front 31

Draw and label Peronospora parasitica. Disease and Host?

Back 31

Disease: Downy Mildew
Host: Crucifer

Did you get:
-infected host cells
-lobular haustoria (lack finger like projections; pinkish color)
-uninfected cells

Front 32

What causes Potato Wart?

Back 32

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

Front 33

What causes Crown Wart of Alfalfa?

Back 33

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

Front 34

What causes Bread Mould?

Back 34

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

Front 35

What are some characteristics to the Zygomycetes?

Back 35

-no zoospores
-asexual apores made in sporangium
-sexual zygospores produced by fusion of morphologically similar gametangia
-well developed hyphae, usually aseptate

Front 36

What are some characteristics to the Subphylum Ascomycetes?

Back 36

-have an asexual conidial state (ANAMORPH) that is more abundant or more important in the epidemiology of the disease than the sexual state (TELEOMORPH)

Front 37

What causes Plum Pockets?
What causes Peach Leaf Curl?

Back 37

Pathogen: Taphrina pruni (Ascomycetse)
-cause one or more kinds of malformations of above ground plant parts

///////////////////////////////
Pathogen: Taphrina deformans

Front 38

What causes Powdery Mildew of Gramineae?

What causes Powdery Mildew of Peas?

Back 38

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

Front 39

How did we prepare Powdery Mildew Cleistothecia for observation?

Back 39

-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

Front 40

What causes Blue Mould Rot of Fruit?

Back 40

Pathogen: Penicillium spp (Deuteromycetes)

-have scattered asci in cleistothecium
-asexual structures include: unicellular conidia in chains; conidiophores; phialides

Front 41

How do you do a tape mount slide?

Back 41

-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

Front 42

Draw Rhizopus spp. Disease and Host?

Back 42

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)

Front 43

Draw Taphrina pruni. Disease and Host?

Back 43

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

Front 44

Draw Erysiphe pisi. Disease and Host?

Back 44

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

Front 45

Draw Penicillium spp. Disease and Host?

Back 45

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)

Front 46

What are some characteristics to Pyrenomycetes?

Back 46

-ascomycetes with perithecia

Front 47

What causes Ergot of Cereals and Grasses?

Back 47

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)

Front 48

What causes Dutch Elm Disease?

Back 48

Pathogen: Ophiostoma ulni

-vascular wilt disease
-read bio 204 stuff if you're interested... shit

Front 49

What are some characterisitics to Loculoascomycetes?

Back 49

-ascomyctes with Ascostroma (pseudothecium is bitunicate)

Front 50

What causes Apple Scab?

Back 50

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

Front 51

What causes Blackleg of Rapeseed and other Crucifers?

Back 51

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

Front 52

What causes Sclerotinia Stem/Soft Rot and White Mould of Various Hosts?

Back 52

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

Front 53

Draw and label Claviceps purpurea. Disease and Host?

Back 53

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

Front 54

Draw and label Venturia inaequalis. Disease and Host?

Anamorph?

Back 54

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

Front 55

Draw and label Sclerotinia sclerotiorum. Disease and Host?

Back 55

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

Front 56

What causes Botryis stem and pod rot of chickpea and lentil; Grey mould of various plants?

Back 56

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**

Front 57

What causes common root rot of wheat and spot blotch?

Back 57

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

Front 58

What causes Net Blotch of Barley?

Back 58

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

Front 59

What causes Tan Spot of Wheat?

Back 59

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

Front 60

What causes Fusarium Root Rot and Head Blight of Cereals?

Back 60

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

Front 61

What causes Fusarium wilts?

Back 61

Pathogen: F. oxysporum & F. avenaceum (anamorphic deut/ascomycete)

-similar symptoms of wilting (leaf discoloration of the vascular tissue due to vascular occlusion(blockage))

Front 62

What causes Dry Rot of Potatoes?

Back 62

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

Front 63

Draw and label Botrytis cinera. Disease and Host?

Back 63

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**

Front 64

Draw and label Cochliobolus sativus. Disease and Host?

Back 64

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)

Front 65

Draw and label Fusarium spp. Disease and Host?

Back 65

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

Front 66

What causes Black spot of canola?

Back 66

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

Front 67

What causes Anthracnose?

Back 67

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

Front 68

What causes Septoria/stagonospora leaf and glume blotch of wheat and grasses?

Back 68

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

Front 69

What causes Ascochyta blight of lentil and chickpea?

Back 69

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

Front 70

What causes Winter Crown Rot of Alfalfa/Snow Mould of Turf Grasses and Winter Cereals?

Back 70

Pathogen: Coprinus psychromorbidus (Basidiomycete)

-several psychrophilic fungi cause snow mould of turf grasses

Front 71

What causes White Heart Rot of Trees?

Back 71

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

Front 72

What causes Armillaria Root Rot of Trees?

Back 72

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

Front 73

Draw and label Alternaria spp. Disease and host?

Back 73

Disease: Blck spot of canola
Host: canola

Did you get:
-hypha (septate)
-macroconidia (tapers off at one end)
-conidiophore (irregular septa intervals

Front 74

Draw and label Colletotrichum lindemuthianum. Disease and Host?

Back 74

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

Front 75

Draw and label Septoria tritici and Stagnospora nodurum. Disease and Host?

Back 75

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

Front 76

Draw and label Ascochyta rabiei. Disease and Host?

Back 76

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)

Front 77

Draw and label Coprinus psychromorbidus. Disease and Host?

Back 77

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])

Front 78

What causes Bunts or Stinking Smuts of Wheat?

Back 78

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

Front 79

What causes Loose Smut of Barley and Wheat?

Back 79

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

Front 80

What causes Covered Smut of Barley?

Back 80

Pathogen: Ustilago hordei (Basidiomycetes - Ustilaginales, smuts)

-has a different life cycle from that of U. nuda
-looks different too

Front 81

What causes Stem Rust of Cereals?

Back 81

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

Front 82

What causes Leaf Rust of Wheat and other Cereals?

Back 82

Pathogen: Puccinia recondita (Basidiomycetes - Uredinales, rusts)

-spermagonia and aecia stage occur on meadow rue
-sure it's not that important

Front 83

What causes Flax Rust?

Back 83

Pathogen: Melampsora lini (Basidiomycetes - Uredinales, rusts)

-an autoecious rust (all 5 spore stages occur on the flax plant)

Front 84

What causes Cedar apple Rust of Saskatoon?

Back 84

Pathogen: Gymnosporangium corniculans (Basidiomycetes - Uredinales, rusts)

-heterocious (on Pomoideae and Juniperus)
-uredia are usually not present in this genus of rust fungi

Front 85

What are some defining characterisitics to the Class Hemibasidiomycetes?

Back 85

-includes: smuts & bunts(Order Ustilaginales), and rusts (Order Uredinales)
-extended dikaryophase
-no basidiocarp
-septate basidium

Front 86

What are some defining characteristis to the Order Ustilaginales?

Back 86

-obligate parasite in nature (yeast like in culture)
-infections are usually systemic
-teliospores replace host tissue

Front 87

What's the main differences between Bunts, Loose smuts and Covered smuts?

Back 87

-Bunts affect wheat
-Loose Smuts affect wheat or barley
-Covered Smuts affect barley

Front 88

What's the difference between Loose smuts and Covered smuts?

Back 88

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

Front 89

How does Loose smut infection occur?

Back 89

-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

Front 90

How does Covered smut infection occur?

Back 90

-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

Front 91

How does Bunt infection occur?

Back 91

-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

Front 92

What are some defining characteristics to the Order Uredinales?

Back 92

-AKA Rusts
-obligate parasites
-infections localized
-autoecious or heteroecious
-microcyclic (few spore types) or macrocyclic (many spore types)

Front 93

Draw and label Tilletia tritici. Disease and Host?

Back 93

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

Front 94

Draw and label Ustilago tritici. Disease and Host?

Back 94

Disease: Loose smut of Barly and wheat
Host: Wheat

Did you get:
-brown spore
-promycelium/basidium
-basidiospore
-hyphae
-fused hyphae
-dikaryotic mycelium

Front 95

Draw and label Puccinia graminis. Disease and Host?

Back 95

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)

Front 96

Draw and label Gymnosporangium corniculans. Disease and Host?

Back 96

Disease: Cedar apple rust
Host: Juniperus scopulurum

Did you get:
-healthy branches
-telial horn (yellow; jelly texture)
-gall (dark brown; gruesome)

Front 97

What causes Blackleg of Potatoes/Soft Rot of Vegetables?

Back 97

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

Front 98

What causes Common Scab of Potatoes and other vegetables?

Back 98

Pathogen: Streptomyces scabies (Bacteria)

-sperficial infection
-scab = cell division and death = raised pustule

Front 99

What causes Halo blight of bean and oats?

Back 99

Pathogen: Pseudomonas syringae (Bacteria)

-brown inside surrounded by a yellow region

Front 100

What causes Fire blight of apple?

Back 100

Pathogen: Erwinia amylovora (Bacteria)

-bacterial ooze apparent
-leaves are thin except for vascular areas

Front 101

What causes Crown Gall?

Back 101

Pathogen: Agrobacterium tumefaciens (Bacteria)

-incites gall formation by hypertrophy and hyperplasia

Front 102

What causes Bacterial Ring Rot of Potatoes?

Back 102

Pathogen: Clavibacter michiganense (Bacteria)

-occurs in a ring internal of the tuber
-accompanied by a milky juice and a foul odour

Front 103

What causes Bacterial wilt of alfalfa?

Back 103

Pathogen: Clavibacter michiganensis (Bacteria)

-curled leaf
-yellow stem
-f'd up root structure

Front 104

What causes common blight on bean?

Back 104

Pathogen: Xanthomona campestris (Bacteria)

-golden color with dark spots

Front 105

What causes Aster Yellow Disease of Various Hosts?

Back 105

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)

Front 106

What causes Tobacco Mosaic Disease?

Back 106

Pathogen: Tobacco Mosaic Virus (virus)

-chlorotic mottling
-leaf distortion
-flower discoloration
-stunting
-wide host range
-mosaicy lines

Front 107

What causes Barly Yellow Dwarf Disease?

Back 107

Pathogen: Barley yellow dwarf virus (virus)

-causes yellowing of grassy tips

Front 108

What causes Leaf roll of potatoe?

Back 108

Pathogen: Potato leaf roll virus (virus)

-curled leaf
-tuber slices show 'net necrosis'

Front 109

What causes Root Knot Nematodes?

Back 109

Pathogen: Meloidogyne spp (nematodes)

-males are stick like
-females are pear like
-saliva induce hypertrophy/plasia resulting in galls

Front 110

What causes Sugar Beet Nematodes?

Back 110

Pathogen: Heterodera schachtii (virus)

-males are worm like
-females are lemon shaped

Front 111

List 4 Non-Parasitic Disease

Back 111

1) Nutrient Deficiencies of Plants

2) Heat and Frost Canker

3) Blast of Cereals
-hot and dry during flowering

4)Herbicide Damage

Front 112

Draw and label Agrobacterium tumefaciens. Disease and Host?

Back 112

Disease: Crown gall
Host: Wide variety

Did you get:
-healthy tisse
-gall area (hypertrophy vs. hyperplasia)

Front 113

Draw and label Aster yellows phytoplasma. Disease and Host?

Back 113

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)

Front 114

Draw and label Meloidogyne spp. Disease and Host?

Back 114

Disease: Root Knot Nematodes
Host: various roots

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