Pl Sc 380 midterm 2

  1. Mycelium
    • body of filamentous fungi 
    • consists of branches called hyphae
  2. dolipore septum
    • central pore surrounded by ring of swollen material extruding from endoplasmic reticulum
    • occurs in Basidiomycota
  3. Phylums in Kingdom: Fungi?
    • Chytridiomycota
    • Zygomycota
    • Ascomycota
    • Basidiomycota
  4. Phylum: Chytridiomycota
    Produce zoospores (single posterior flagellum), limited mycelium (coenocytic)
  5. Olpidium brassicae 
    • root parasite
    • wide host range (crucifers)
    • resting spores -> zoospores in spring -> infections in new cells that produce sporangia -> more zoospores
    • vector of tobacco necrosis virus
  6. Scientific name of root parasite vector of tobacco necrosis virus?
    Olpidium brassicae 
  7. Synchytrium endobioticum 
    • cause of potato wart disease
    • infected tubers not usable
    • main measure of control: exclusion/quarantine
  8. Scientific name of potato wart disease?
    Synchytrium endobioticum
  9. Phylum: Zygomycota
    • Terrestrial fungi
    • produce non-motile asexual spores in sporangia
    • produce zygospores (sexual spores), very thick walled survival structures
    • hyphae are coenocytic
  10. Genus: Rhizopus 
    • weak pathogens
    • spores are formed dry (100% terrestrial)
    • has sporangiophores, sporangiums, rhizoids
    • bread moulds
  11. Fungus that grows on dung, model system for studying fungi
    Phycomyces blakesleanus 
  12. Phylum: Ascomycota
    • "sac fungi"
    • asexual spores=conidia
    • septate mycelium
  13. Sexual spores produced by phylum Ascomycota?
    Ascospores, contained within a sac-like structure called an ascus
  14. A group of asci is a(n)_____
  15. Naked ascocarp
    not enclosed in an ascocarp
  16. cleistothecium
    one or more asci entirely enclosed in a protective sexual fruiting body
  17. perithecium
    asco enclosed in a flask-shaped structure having a pore
  18. apothecium
    a layer of asci supported in a cup-shaped structure
  19. Holomorph
    whole organism
  20. anamorph
    asexual or imperfect stage
  21. telomorph
    sexual or perfect stage
  22. Order: Erysiphales
    • powdery mildews
    • prolific conidiation
    • biotrophic pathogens
    • sexual stage for survival/overwintering and genetic recombination
  23. Powdery milews produce cl______
  24. Blumeria graminis
    • cause of powdery mildew of cereals and grasses
    • Anamorph:??
    • important in AB and prairies
  25. Scientific name of powdery mildew of cereals and grasses
    Blumeria graminis
  26. Management of powdery mildew of wheat
    • some resistant cultivars available
    • crop rotation
    • some systemic and foliar fungicides work
  27. HR
    • hypersensitivity reaction (of the host)
    • host cells kills itself to kill pathogen
  28. Order: Sphaeriales
    produce perithecia, dark coloured usually firm walls
  29. Cryphonectria parasitica
    • causes chestnut blight
    • cankers in bark
  30. Scientific name of chestnut blight
    Cryphonectria parasitica
  31. Control of chestnut blight?
    • no control available
    • but hypovirulent strains found in 1950s
  32. Hypovirulent Strains
    • found for chestnut blight 
    • contain double stranded RNA, causes superficial cankers (CH strain)
    • cankers caused by virulent strain can be controlled by innoculation with the CH strain
    • doesn't work as well in North America bc our trees are more susceptible than European chestnut
  33. Order: Hypocreales
    • also produce perithecia, light coloured red or blue
    • includes ERGOT pathogen
  34. Claviceps purpurea
    • causes ergot of cereals worldwide
    • important due to production of sclerotia in the spike (replaces grain)
  35. Scientific name for ergot of cereals
    Claviceps purpurea
  36. Hosts of ergot of cereals
    rye, wheat, barley, oats, other grasses
  37. seedlots containing _______ of ergot of cereals considered dangerous for consumption
  38. Honeydew stage of disease cycle of ergot in wheat
    On an immature sclerotium, droplets of conidia appear (honeydew) before forming conidium
  39. Management of ergot of cereals
    • crop rotation 1-2years
    • deep ploughing
    • use clean seed (remove sclerotia)
  40. sclerotium
    hard, resistant multicellular resting boy usually with a differentiated rind and medulla, under favorable conditions can germinate to produce mycelium or sexual/asexual fruiting bodies
  41. Nectria cinnabarina
    • Causes lots of twig and stem canker diseases
    • weak pathogen, usually attacks weakened or stressed trees
    • produces diffuse cankers
  42. Scientific name of cause of lots of twig and stem canker diseases
    Nectria cinnabarina
  43. Management of N. cinnabarina
    • not really important so control not usually thought of
    • remove branches with fruiting bodies
    • give good growing conditions and reduce wounds
  44. Order: Heliotales
    produce apothecia
  45. Sclerotinia sclerotiorum
    • cause of white rot in canola 
    • host range very broad, not very specialized 
    • grasses and cereals are immune
  46. scientific name of white rot in canola
    Sclerotinia sclerotiorum
  47. White stem rot symptoms
    • appearance of white fluffy mold (mycelium) on infected parts of plant
    • sclerotia often imbedded in mycelium (start white then turn black when mature)
  48. Management of white stem rot
    • crop rotation with cereals and grasses
    • broad-leaf weed control
    • fungicides (foliar sprays)
    • disease forecasting (risk maps, etc)
    • genetically more calcium in host?
    • clean seed
    • deep ploughing (bury sclerotia)
  49. Order: Pleosporales
    produce pseudothecia
  50. Apiosporina collinsii
    • causes sooty mold of saskatoon
    • entire leaf covered w pseudothecia, dull black colour
    • second symptom formation of witches' brooms
  51. Scientific name of sooty mold of saskatoon
    Apiosporina collinsii
  52. Leptosphaeria maculans
    • blackleg of canola
    • sexual stage: pseudothecia
    • asexual stage: pycnidia
  53. Scientific name of blackleg of canola
    Leptosphaeria maculans
  54. Hosts of blackleg of canola
    canola, rapeseed, wild mustard, stinkweed, cabbage, etc
  55. Blackleg of canola symptoms
    • fungus attacks leaves, stems, pods
    • leaf lesions grayish, dotted w pycnidia
    • stem lesions at base of plant
    • premature plant death
  56. Sources of inoculum for blackleg of canola
    • crop residues (ascospores)
    • seedborne mycelium
    • other host species and volunteers
  57. Management of blackleg of canola
    • genetic resistance
    • crop rotation to non-host species
    • removal of infected residues (tilling, etc)
    • clean or fungicide-treated seed
  58. Pyrenophora tritici-repentis 
    • cause of tan spot of wheat
    • most cultivars in AB sensitive to Ptr Tox A
  59. scientific name for tan spot of wheat
    Pyrenophora tritici-repentis
  60. symptoms of tan spot of wheat
    • oblong tan-coloured nectrotic blotches surrounded by a yellow halo
    • at least 8 different known races
    • races 1 and 2 predominant here
  61. Control of tan spot of wheat
    • tillage
    • crop rotation
    • resistant cultivars
    • foliar fungicides to protect flag leaf
  62. "imperfect fungi"
    • asexual fungi; sexual reproduction and structures lacking or unknown
    • when sexual structures identified, teleomorph given name and fungus reclassified
  63. setae
    bristle-like structures
  64. acervulus
    cushion-like fruiting body bearing conidiophores, conidia, and sometimes setae
  65. synnema
    compact or fused, generally upright conidiophores, with branches and spores forming a headlike structure
  66. sporodochium
    a superficial, cushion-shaped asexual fruiting body consisting of a cluster of conidiophores
  67. pycnidium
    an asexual, globose or flask-shaped fruiting body containing conidia
  68. Phylum: Deuteromycetes
    Order: Hyphales
    produce spores freely exposed to the air
  69. Graphium ulmi 
    • casual agent of dutch elm disease
    • has a teleomorph, but in many areas sexual reproduction extremely rare
    • produces synnemata
  70. scientific name of dutch elm disease
    Graphium ulmi
  71. Dutch elm disease symptoms
    • worldwide pandemic 
    • initial: wilting portions of crown, later yellowing, may spread or entire tree may die
    • discolouration: vascualar staining from fungus with grums, gels
  72. Vector of dutch elm disease
    european elm bark beetle and native elm bark beetle
  73. Management of DED
    • currently no resistance
    • don't prune trees when beetle is active
    • don't move infected logs
    • fungicides can be injected at base of tree
    • control elm bark beetle with pesticides
  74. Fusarium spp.
    • causes fusarium head blight or scab
    • wide host range incl. wheat, barley, oat, corn, rye 
    • facultative parasites can infect all plant parts
  75. Yield losses due to fusarium?
    • due to floret sterility and poor seed filling
    • seed germination impaired
    • infection alters milling and baking qualities
    • low tolerance and grade reductions for fusarium damaged kernels
  76. Control of fusarium head blight
    • fungicide seed treatment if evidence of seed infection
    • seed cleaning
    • rotation with non-host crops
    • removal of host residue
    • plant in cold soil 
    • genetically resistant cultivars
    • exclusion
  77. Order: Sphaeropsidales
    pycnidial fungi
  78. Septoria tritici
    cause of septoria leaf blotch of wheat
  79. scientific name for septoria leaf blotch of wheat
    Septoria tritici
  80. septoria leaf blotch of wheat symptoms
    • yellow blotches on leaves 
    • lesions with numerous black pycnidia
    • stubble borne disease
  81. Phylum: Deuteromycetes
    Order: Agonomycetales
    no spores, only mycelia and microsclerotia produced
  82. Rhizoctonia solani
    • teleomorph? 
    • cause of dampening off and root and foot rot of canola
  83. Anastamosis
    the fusion between the branches of the same or a different structure (ex. hyphae) to make a structure
  84. Scientific name of cause of seedling blight of canola?
    Pythium spp.
  85. Management of seedling blight of canola
    • No resistance due to complex of pathogens
    • firm seed bed
    • optimum sowing depth
    • seed treatments
Card Set
Pl Sc 380 midterm 2
lecture 7-13, guest lectures 4 and 5