Ceratocystis, Hawaiʻi & Rapid ʻŌhiʻa Death Lisa Keith, Research Plant Pathologist USDA-ARS, DKI PBARC, Hilo, HI [email protected] Ceratocystis, Hawaiʻi & Rapid ʻŌhiʻa Death Lisa Keith, Research Plant Pathologist USDA-ARS, DKI PBARC, Hilo, HI [email protected] Teamwork! Flint Hughes (USDA Forest Service) & J. B. Friday (UH Mānoa CTAHR) Lionel Sugiyama, Blaine Luiz, Wade Heller, Marc Hughes & Eva Brill ROD Research Partners: Outline •Ceratocystis fimbriata •‘Ōhi‘a, Metrosideros polymorpha •Rapid Ōʻhiʻa Death (ROD): What is it and how does it work? •C. fimbriata in Hawaiʻi •Epidemiology of Ceratocystis C. fimbriata and spp. • Wide geographical distribution and host range (woody and herbaceous plants) • Fungus-Host –> 250 records world-wide including 31 plant species and 14 plant families • Wound parasites; disrupt water movement; cankers; necrosis of inner bark; discoloration of sapwood; wilt and canker stain pathogen; death • Important Tree Diseases (not found in Hawaiʻi): • C. fimbriata s.l. – Sweet potato, Mango, Eucalyptus, Taro, Cacao, Citrus spp., Coffee, Rubber tree, Prunus spp., Fig, Poplar, Acacia spp. & Kiwi……… at least 40 genera in 35 countries • C. manginecans - Mango sudden decline (Oman and Pakistan) • C. platani - Canker stain disease of sycamore (Europe) • C. fagacearum - Oak wilt (USA) • C. smalleyi – Hickory canker (USA) ‘Ōhi‘a, Metrosideros polymorpha, Myrtaceae • Dominant tree in 80% of Hawaiian forests Photo: JB Friday • Both primary succession and old-growth species • Forms almost pure stands; Morphologically diverse • Important for watershed, wildlife, and cultural values Photo: JB Friday Photo: Jack Jeffery Photos: JB Friday Rapid ‘Ōhi‘a Death (Pure culture on a plate) • Causing widespread mortality of ‘Ōhi‘a (M. polymorpha) on Photo: Marc Hughes Hawaiʻi Island • Characterized by canopy browning, wilt, death, and defoliation • Caused by two new wound colonizing fungi of Ceratocystis Isolation, ID & Pathogenicity Tests Lab Symptoms & Signs Ceratocystis sp. A Ceratocystis sp. B 40X 40X 40X 40X 40X Control 400X 400X Field Symptoms & Signs Ceratocystis sp. A Ceratocystis sp. B 400X Ceratocystis Isolates in Hawaiʻi (‘Invasive Species’) • Sweet potato pathogen; In HI >75 years; Only infects sweet potatoes; Worldwide distribution http://en.wikipedia.org/wiki/Ceratocystis_fimbriata • Syngonium pathogen: Isolated at a BI nursery in 1979/2016; Broadly distributed (Florida, Brazil, Australia); Closely related to strains that affect crops (coffee, cacao) and forest species (eucalyptus, sycamore) Photo credit Scot Nelson • Taro pathogen: First isolated in 1990’s on Oahu and Kauaʻi; minor pathogen on storage roots http://www.public.iastate.edu/~tcharrin/FimbDis.html • ‘Ōhi‘a pathogens: Two new species isolated from dead and dying ‘Ōhi‘a trees Fungal Biology/Host Range/Resistance Testing Ag & Nursery Crops London Plane Taro Syngonium M. polymorpha varieties and spp. Sweet potato Coffee 2 New Species of Ceratocystis ? sp. B ? sp. A http://www2.padi.com/blog/2011/05/02/teach-your-child-to-conserve-our-oceans/hawaii-map/ • Ceratocystis species that are pathogens of other crops previously found in Hawaiʻi do not cause disease on ʻōhiʻa • There is no evidence that the Syngonium or taro isolates directly evolved into the ʻōhiʻa pathogenic strains, only that they originated in similar parts of the world What are the potential ways Ceratocystis moves across the landscape and infects trees? Root Graft Transmission Canker stain of plane tree Oak wilt Tsopelas et al. 2017 Texasoakwilt.org Direct Transmission by Insects Mango Sudden Decline A. mango bark beetle, Hypocryphalus mangiferae, B. fungal perithecia Oak wilt fungal mat Galdino et al. 2017 J. Juzwick US Forest Service Indirect Transmission by Insects* Laurel wilt-affected Redbay trees Ambrosia beetle boring dust (frass) contains viable propagules and can spread via wind Hughes et al. 2015 Humans and Animals* Animal wounds Human activity Photo: JB Friday Photos: Wade Heller Human transport Initial mortality was observed in the Puna District of Hawaiʻi Island 29,632 ha 2008 9,950 ha 16,238 ha 37,359 ha 1,299 ha 2012 347,069 total hectares (1 ha = 2.47 acres) 252,591 ha Pictometry courtesy of USGS Rapid ‘Ōhi‘a Death 2 Diseases • Sp. A (ʻŌhiʻa Wilt) and Sp. B (ʻŌhiʻa Canker) overlap, but have different distributions on Hawaiʻi Island • Visual symptoms are similar, but wood colonization patterns are different • Determine what trees/plants are vulnerable Species A to attack and what plants can act as carrier Species B hosts Map prepared by Blaine Luiz • Research and testing informs management DLNR Division of Forestry and Wildlife remote sensing: currently >30,000 ha of decisions ‘ōhi‘a forest affected (>10% mortality) Thank you Questions? For more information: www.RapidOhiaDeath.org.