lab_quiz2 - Copy

lab_quiz2 - Copy - pathogen spreads. Sporangiophores emerge...

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Lab Quiz #2 Name___________ Date_____________ Section_____________ 1. (1 pt) What is the characteristic sexual spore of the oomycetes? Oospore 2. (1 pt) List three asexual spores produced by members of the oomycetes. Zoospores, Conidia, Chlamydospore 3. (1 pt) Which spore type is motile and responsible for infection? Zoospores 4. (1 pt) What is the branched structure that bears (produces) sprorangia? Sporangium 5. (1 pt) What are the symptoms and signs of downy mildew disease? Symptoms of downy mildew are light yellow spots that become dark grey and enlarge. Signs include sporophores on the underside of the leaf and hyphae. 6. (3 pts) Give two typical above-ground symptoms of root rot diseases. What is happening below-ground to cause these symptoms? Stunted or slow growth and wilted leaves. The roots are rotting and therefore the plant cannot take up water. 7. (5 pts) Describe the disease cycle for Phytophthora late blight of potato. The pathogen overwinters in the potato as mycelium and as the potato germinates the
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Unformatted text preview: pathogen spreads. Sporangiophores emerge on the new leaves and release their sporangia in the wind to spread. 8. (2 pts) What is damping off? List a pathogen (genus) that can cause damping off. Damping off is the rotting of a seed or young plant. Pythium is a common pathogen genus that causes this. 9. (5 pts) Describe the infection process of zoospores, including mobility, attraction, and site of infection for root rots caused by species of Phytophthora and Pythium The zoospores are released and swim through surrounding water before forming a cyst that starts an infection after germinated by a germ tube. Zoospores are attracted by chemical gradients in the soil to the roots of a host. In Phytophthora chlamydospores are also formed to ensure the survival of propagules. Bonus (1pt): Give the correct taxonomic sequence for family , class , phylum , genus , and order . Phylum Class Order Family Genus...
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This note was uploaded on 03/22/2008 for the course PP 315 taught by Professor Shew during the Spring '08 term at N.C. State.

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lab_quiz2 - Copy - pathogen spreads. Sporangiophores emerge...

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