1. Sudden oak death Phytophthora ramorum Sudden oak death Phytophthora ramorum

2. Sudden oak death Phytophthora ramorum

3. Black pod disease of cacao P. megakarya P. capsici P. palmivora

4. Downy Mildew - Grape Plasmopora viticola Obligate biotrophic pathogen Photosynthetic area lost Fruit yield reduced & Fruit rot

5. Downy Mildew: Symptoms and Signs Leaf spots are yellowish on upper surface, white and downy on lower surface. Late-season infection results in a mosaic of yellow, red, and brown angular spots. Early symptoms Late symptoms Signs

6. Downy Mildew: Symptoms and Signs Diseased fruit are off-color, shrivel and become covered with white, downy hyphal growth.

8. Downy Mildew of Grape Sporangia Downy Mildew Plasmopara viticola Source of secondary inoculum Inoculum to new leaves and fruit

9. Dew and rain contributes to duration of leaf wetness

12. Downy Mildew of cucurbits Pseudoperonospora cubensis

13. Downy mildew of corn -Sclerophthora macrospora

14. Downy mildew of sugar cane – Peronosclerospora sacchari

15. Oomycetes: Aphanomyces Spores Sporangiophore

16. Oomycetes: Aphanomyces Exit pore

17. Oomycetes Aphanomyces Sporangium is a modified hypha Primary spores exit and aggregate at end of sporangium Primary spores release zoospores Spores Sporangiophore

18. Oomycetes Aphanomyces Primary spores Two means to resume growth –Germinate to germ tube –Release zoospore through pore Exit pore

19. Albugo candida

20. Chytridiomycota – “chytrids” Simple fungi Produce motile spores Mostly saprobes and parasites in aquatic habitats Could just as well be Protists Fig 31.5 Chytridium growing on spores

21. Part of a grass root with large sporangia (sp) of Olpidium brassicae within the root cells. At maturity the sporangia release zoospores through exit tubes (et). Several zoospore cysts (cy) can be seen on the root. (a) Zoospore cysts have germinated to produce short tubes that penetrated the root cell wall then released the cyst content as a naked protoplast into the host cell. Stellate resting spores seen in early stages of development (b) and in mature form (c).

22. Potato wart - Synchytrium endobioticum E. Çakır

23. Zygomycota – “zygote fungi” Sex - zygosporangia Asex - common Hyphae have no cross walls Grow rapidly Mycorrhizae Fig 31.6 Rhizopus on strawberries

24. Rhizopus fruit rot

30. ConidiaAscospore Asexual SporesSexual Spores Ascomycete Spores

32. Ascocarp = fruiting body containing ascospores in asci Ascospore = sexual spore Ascus (asci) = ‘sack’ containing 8 ascospores Ascus hyaline colored

33. No Ascocarp Cleistothecium Perithecium (pseudothecium or pseudoperitheciu m) Apothecium

35. http://vegetablemdonline.ppath.cornell.edu /NewsArticles/Cuc_Downy.htm http://vegetablemdonline.ppath.cornell.edu/factsheets/Onions_Downy.htm#Click