EPWS 310 EXAM 2, Fall 1999

1. Define the following terms:













zoospore cyst




2. Make a simple dichotomous key (flow chart) to differentiate the Myxomycetes, Plasmodiophoromycetes, Oomycetes, Zygomycetes, and Chytridiomycetes.

















3. What is the nuclear state of Oomycete and Zygomycete mycelia? When does plasmogamy, karyogamy, and meiosis occur for members of each class?












4. As manager of a nursery operation, how would you control Pythium damping off of bean seedlings? Contrast this with control of slime mold on turf.











5a. Compare and contrast the disease cycle of Phytophthora capsici causing root rot on chile with Phytophthora infestans causing late blight of potato.















5b. How do the control of these diseases differ?













6. What are the survival structures and primary inoculum, for Plasmodiophora brassicae, and survival structures, primary inoculum, and secondary inoculum for Rhizopus sp? What diseases are caused by these fungi?








7. a) What environmental conditions favor fungi in the Peronosporales and why?



b) How can you differentiate Pythium from Phytophthora?



c) What are the two ways that downy mildew fungi overwinter?


d) What are the two ways that Chytridiomycetes lead to losses?



8. Contrast the penetration, colonization, and the dispersal of Peronospora and Phytophthora and the diseases they cause.