Phytophthora Diseases

1. Phytophthora Diseases Gary W. Moorman Penn State Plant Pathology & Environmental Microbiology

2. Late blight of tomato ( Phytophthora infestans )

3. Phytophthora , Oomycete not a true fungus Hyphae Chlamydospores Sporangia Antheridia/ oogonia Zoospores Cell walls contain cellulose Usually has 2n chromosomes

4. Antheridium Oogonium APS Digital Image Collection

5. Phytophthora , sexual reproduction A1 + A2 mating types required

6. 20-50 Zoospores per sporangium Sporangium APS Digital Image Collection

7. Phytophthora plant pathogens soil-borne??? …usually plant-borne APS Digital Image Collection

8. Sporangium Zoospore Release Oospore germinating by germ tube Oospore Formation Germinating oospore by sporangium Sporangium Sporangium Zoospore Release Sporangiophore and sporangia Zoospores Oogonium & Antheridium Life history and disease cycle of Phytophthora A1 & A2 mycelium Asexual reproduction Sexual reproduction

9. Wet conditions, 65  F - 70  F sporangia within 4 hours Each sporangium > 20 to 50 zoospores released within 1 hour Phytophthora activity

10. Phytophthora dispersal Short distances Splash Wind Long distances Movement of plants or soil

11. Phytophthora cactorum P. citrophthora P. citricola P. cryptogea P. drechsleri P. lateralis P. megasperma …many more P. parasitica P. syringae P. nicotianae P. ramorum top diebacks, leaf spots, stem cankers

12. Phytophthora cinnamomi infects 900 different species Many Phytophthora species have a wide host range:

13. Phytophthora root rot APS Digital Image Collection

14. Douglas-fir infected with Phytophthora spp. APS image collection

15. Photo: Jennifer Parke, Oregon State University

16. Phytophthora root rot APS Digital Image Collection

17. Severe root rot

18. Phytophthora cinnamomi on Ilex glabra ‘Shamrock’

19. Top dieback APS Digital Image Collection

20. Top dieback V-shaped dead areas APS Digital Image Collection

21. Symptoms on camellia Photos: Oregon Dept. of Agriculture & Cheryl Blomquist, CDFA

22. Symptoms on camellia Photo: Cheryl Blomquist, CDFA

23. P. ramorum symptoms on Kalmia Photo: DEFRA

24. Sun scorch Gray spot on sun scorched leaves Similar symptoms – not Phytophthora Photo: Rich Regan, Oregon State University

25. Photo: Peter Angwin, USDA-Forest Service Not Phytophthora Cercospora on Kalmia

26. Bleeding cankers beech

27. beech

28. Photo by Joseph O'Brien Bugwood.org image collection Reddish-brown discoloration cambium area infected with Phytophthora spp.

29. Phytophthora cactorum Phytophthora citricola Phytophthora plurivora Phytophthora on European beech ( Fagus sylvatica ) Weiland , Nelson and Hudler . 2010 Plant Disease 94: 1009-1014

30. Taxus

31. Coastal live oak infected with Phytophthora ramorum APS image collection

32. Phytophthora ramorum Photos: Mike McWilliams, ODF & Bruce Moltzen, Missouri Dept. of Conservation “bleeding”

33. Phytophthora ramorum Sudden …usually slow Oak …many other suscepts Death …often not lethal

34. African violet infected with Phytophthora spp. APS image collection Penn State image collection

35. Hosta infected with Phytophthora spp. APS image collection

36. Lavender infected with Phytophthora spp. APS image collection

37. Polemonium infected with Phytophthora spp. APS image collection

38. Catharanthus = annual vinca infected with Phytophthora spp. APS image collection

39. Phytophthora nicotianae on petunia

40. Phytophthora detection Phytophthora species in general: Antibody test (ELISA) Semi-selective media Specific Phytophthora (P. ramorum ) Nested PCR DNA test ELISA Plating PCR Photo: Natalie Goldberg, New Mexico State University

41. Phytophthora detection Baiting:

42. If you collect a sample Collect various stages of symptoms. Photo symptoms and environment.

43. Packaging a sample DRY paper towel Double bag and seal Crush proof box Sample submission form outside of bags Overnight express Monday-Thursday

44. Phytophthora ramorum Photo: UC Davis & UC Berkeley Phytophthora ramorum in culture Chlamydospores Sporangia releasing zoospores

45. QUESTIONS???