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Deuteromycetes and Lower Fungi

Deuteromycetes and Lower Fungi. Zygomycetes. Zygomycetes. No septa Anamorph: sporangia Sporangiospores – nonmotile Facultative parasites. Rhizopus Soft Rot Rhizopus spp. Post harvest rot of fruits and vegetables Stem rot of poinsettia Has macerating enzymes Has rhizoids.

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Deuteromycetes and Lower Fungi

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  1. Deuteromycetes and Lower Fungi

  2. Zygomycetes

  3. Zygomycetes • No septa • Anamorph: sporangia • Sporangiospores – nonmotile • Facultative parasites

  4. Rhizopus Soft RotRhizopus spp. • Post harvest rot of fruits and vegetables • Stem rot of poinsettia • Has macerating enzymes • Has rhizoids

  5. Rhizoids – short thin hyphae growing in root-like fashion

  6. Rhizopus spp. - Teleomorph Zygosporangia

  7. Rhizopus spp. - Anamorph Sporangia with nonmotile sporangiospores

  8. Rhizopus Soft Rot Symptoms and Signs

  9. Rhizopus Life Cycle

  10. Deuteromycetes(Fungi Imperfecti) • Asexual stages of many Ascomycetes and some Basidiomycetes • Causes many important diseases • Often the secondary disease cycle • Spore stage is conidia

  11. Southern Corn Blight • Caused by Cochiobolus maydis (has been classified as Helminosporium maydis and Bipolaris maydis) • Caused by race T of C. maydis • Caused major epidemics in corn in 1970 • Corn containing Texas male sterile cytoplasm is susceptible

  12. Southern Corn Blight • Hybrid seed corn was expensive when tassels from plants being used as the female parent had tassels removed by hand. • By end of the 1960’s, all seed corn was produced using ‘Texas Male Sterile Cytoplasm’ which made the pollen of the female parent sterile. Male and female corn rows being used to produce hybrid seed corn

  13. Southern Corn Blight • In 1970, epidemic of corn blight by new race specific for plants with Texas male sterile cytoplasm found in southern US • 15% of US corn supply loss in 1970 ( enough to feed sufficient cattle to make 30 billion Big Macs • Projects were for 90-100% loss in 1971. Why did this not happen? Seed companies produced seed the old fashion way in South America during winter of 1970-71. Southern blight symptoms Field killed by southern corn blight. Note green weeds.

  14. Southern Corn Blight Disease Cycle

  15. Early Blight Alternaria solani • May be seed borne • Can over winter on debris • Spread by wind and rain • Produces nonspecific toxins

  16. Symptoms of A. solani

  17. A. solani Life Cycle

  18. Fusarium Wilt Fusarium oxysporium • Causes severe losses in vegetables, flowers, cotton, and tobacco, banana ans sugarcane • Soil inhabitant • Over winters in debris as chlamydospores

  19. Symptoms and Signs of Fusarium Wilt

  20. F. oxysporum Life Cycle

  21. Fusarium Wilt / Root Knot Nematode Interaction • Increased incidence of root knot nematode infection increases problems with Fusarium wilt • Mode of action is thought to be wounding by nematodes.

  22. Verticillium WiltV. albo-atrum and V. dahliae • Soil inhabitant • Over winters as microsclerotia • Occurs in field crops such as cotton, vegetables such as tomatoes, and in hard wood trees

  23. Signs of Verticillium Wilt Conidia and Conidiophores Microsclerotia

  24. Symptoms of Verticillium Wilt

  25. Verticillium Wilt of Cotton(Bronze Wilt)

  26. Occurs throughout the season Favored by temps > 23oC Chocolate brown discoloration throughout stem Occurs late in season Favored by temps < 23oC Dark brown discoloration in vascular tissue throughout stem Comparison of Fusarium and Verticillium Wilts Verticillium Fusarium

  27. Disease occurs in patches Survives as chlamydospores Has macro and microconidia Can be seed borne Diseased plants scattered Survives as microsclerotia Has one form of conidia Is not seed borne Comparison of Fusarium and Verticillium Wilts Fusarium Verticillium

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