DNB overview

Overview of Dothistroma Needle Blight

Transcript

1. Dothistroma Needle Blight Dr Kath Tubby
2. 24/04/2015 2 Overview • Taxonomy and nomenclature • Historical changes and current situation • Distribution of DNB • Worldwide and European • Biology and epidemiology • Life cycle, dothistromin, symptoms and infection process, conditions for infection and dispersal, incubation period • Hosts and impact • Pine and non-pine hosts, example of symptoms • Loss in yield, mortality, timber quality • Control methods • Silvicultural, chemical, tree breeding
3. 24/04/2015 3 Taxonomy and nomenclature A ‘simplified’ history: • In Europe, DNB was first reported in St Petersburg, Russia 1911 and described as Cytosporina septospora which was then reclassified as Septoriella septospora in 1931. Between 1928 and 1948 it was then confused with Brunchorstia pinea in Russia, Romania and Spain. • In the USA, DNB was first reported in Idaho in 1917 and described as Actinothyrium marginatum, and then between 1924 and 1928 further confused with Lecanosticta acicola, Leptostroma decipiens, Cryptosporium acicola and Septoria acicola. • In the USA in 1941, Hulbary described a new species, Dothistroma pini, from samples taken in Illinois AND realised that the previous USA samples had been incorrectly identified. • In Europe in 1954, the disease was reported in a UK nursery and described as Dothistroma pini Hulbury.
4. 24/04/2015 4 Taxonomy and nomenclature A ‘simplified’ history continued…. • Between 1967 and 1969 we realised Europe’s Cytosporina septospora was the same fungus as the Dothistroma pini causing problems in the USA and Africa, and the name Dothistroma septospora was proposed. These two Dothistroma names were then used for many decades. • In 2004, Phylogenetic relationships between isolates from five continents and 13 countries were examined, and Irene’s group found two Dothistroma species causing disease: • one with a worldwide distribution renamed Dothistroma septosporum • one limited to North Central USA, renamed Dothistroma pini.
5. 24/04/2015 5 Taxonomy and nomenclature A simplified history of the Dothistroma teleomorphs: • The teleomorph is rarely found. • In Europe in 1957 the teleomorph was first described as Mycosphaerella pini on dead needles from Denmark but no link to the anamorph was made • In Canada in 1966, the teleomorph was linked to what is now known as Dothistroma septosporum, and named Scirrhia pini • In 1966, Scirrhia pini was re-classified as Eruptio pini • In 2001, Phylogenetic analysis re-classified the teleomorph as Mycosphaerella pini
6. 24/04/2015 6 Mycosphaerella pini Current status Dothistroma pini Dothistroma septosporum Unknown Dothistroma Needle Blight Anamorph Teleomorph Disease Scirrhia pini Current legislation
7. 24/04/2015 7 World distribution Map should also include: Ethiopia, Mexico and Peru Bosnia Herzegovina, Macedonia, Montenegro, Norway, Russia, Sweden, UK – Northern Ireland, UK – Wales and the Ukraine (Presumed) Dothistroma septosporum
8. 24/04/2015 8 o 1997 1983 1911 1990 1955 1995 1961 1966 1989 1968 2000 1975 2000 1990 1975 2007 2008 2008 2005 1977 1977 2005 2008 2007 1986 Before 1986 2008 2008 1980-1981 1958 2004 2009 2009 1986 2011 European distribution (Presumed) Dothistroma septosporum
9. 24/04/2015 9 Known D. pini distribution • North central USA (Michigan, Minnesota and Nebraska) • France (possible since 1907), Hungary, SE Russia and the Ukraine • The two Dothistroma species are only distinguishable using molecular methods.
10. 24/04/2015 10 Symptom and infection process
11. 24/04/2015 11 Symptom and infection process
12. 24/04/2015 12 Dothistromin • Toxin produced by both Dothistroma spp. • Responsible for the red colouration produced in the necrotic areas • Structurally similar to versicolorin B (an aflotoxin precursor produced by some Aspergillus spp.) • Induces plant defences and shown to provide a competitive advantage against other fungi (in vitro) • Levels produced vary by >500 fold • Weak mutagen and clastogen and thus potentially carcinogenic
13. 24/04/2015 13 Required conditions • Natural spore dispersal • Water is essential • Spores released in water and become caught droplets • Local dispersal is from runoff and splash • Highest infection within 100m, dramatic drop off by 200m but still occurring at 300m • Longer dispersal probably via wind driven rain and mists and cloud • Conidia trapped in mist 3m feet above canopy
14. 24/04/2015 14 Required conditions • Spore germination (and mycelia growth) • Humidity >75% • Availability of free water • Temperature 5-30oC, optimum 17-22oC • Temperature can be raised and lowered and spores will germinate when returned within the limits • Light – no impact
15. 24/04/2015 15 Required conditions • Incubation period • Very variable and dependent on climatic conditions (debates over exact conditions but warmer and higher light intensities generally = faster) and host type • E. Africa = 4 to 15 weeks • New Zealand = 6 to 38 weeks • Chile = 8 to 16 weeks • Central USA = 11 to 16 weeks (D. Pini) • Pacific USA = 4 to 12 weeks • Japan = 8 to 26 weeks • China = 8 to 36 weeks • Serbia = 6 to 10 weeks • In Europe fruit bodies are generally visible by late autumn or winter but most abundant in spring and summer
16. 24/04/2015 16 • Persistence on fallen needles • In NZ on P. radiata • Suspended - at least for four but less than six months • Litter layer - at least for two but less than four months • In UK on P. nigra ssp. laricio • Suspended - at least for seven months • Litter layer - at least for five months Persistence of Dothistroma
17. Lophodermella sulcigena and L. conjuncta -Young SP , CP ( and occasionally LP) - Current year’s needles green - One year old needles show diffuse banding (green – yellow – straw coloured). These fairly rapidly die and turn grey in colour (SP) -Fruit bodies dark but under a pale skin, usually long (>2mm), thin and longitudinally aligned. - Often only one needle of the pair infected Briefly: Other needle pathogens
18. Lophodermium seditiosum - SP and occasionally LP and CP - Current year’s needles still green, but shoot maybe stunted. - 2nd year needles affected; complete browning /needle loss likely by early summer; Needles may droop prior to casting. -Symptoms may be one-sided on shoot - Fruit bodies, if present, large & easily visible rugby-ball-shaped with central longitudinal split, black when wet or grey when dry, in lines. Other needle pathogens
19. Ramichloridium pini - LP although susceptibility varies with provenance - Needles tend to die from the base upwards - Affected needles usually all at about the same stage, and a single colour (i.e. without banding). - Current year’s shoot dead whilst older needles still green. - Shaving away bark on shoot may reveal necrotic internal woody tissues. Other needle pathogens
20. 24/04/2015 20 Highly susceptible - - P. attenuata, P. x attenuradiata, P. brutia, P. canariensis, P. cembroides, P. contorta var. latifolia, P. engelmannii, P. halepensis, P. jeffreyi, P. muricata, P. nigra subsp. laricio, P. nigra subsp. nigra, P. pinea, P. ponderosa, P. radiata, P. sabineana, P. sylvestris, P. thunbergii Moderately susceptible - - P. bungeana, P. canariensis, P. caribaea, P. coulteri, P. cubensis, P. densiflora, P. echinata, P. echinata x taeda, P. elliottii, P. flexilis, P. jeffreyi, P. kesiya, P. lambertiana, P. massoniana, P. monticola, P. mugo subsp. Mugo, P. muricata, P. occidentalis, P. palustris, P. pinaster, P. pungens, P. radiata var. binata, P. resinosa, P. roxburghii, P. strobiformis, P. strobus, P. taeda, P. thunbergii Slightly susceptible - P. aristata, P. ayacahuite, P. contorta, P. coulteri, P. devoniana, P. elliottii, P. elliottii var. densa, P. hartwegii, P. heldreichii, P. koraiensis, P. merkusii, P. montezumae, P. monticola, P. nigra subsp. nigra, P. oocarpa, P. patula, P. pseudostrobus, P. rigida, P. sabineana, P. serotina, P. sibirica, P. strobus, P. strobus L. var. chiapensis, P. sylvestris, P. tabuliformis, P. taeda, P. torreyana, P. wallichiana Susceptibility unknown - P. albicaulis, P. arizonica var. cooperi, P. banksiana, P. cembra, P. clausa, P. contorta x banksiana, P. contorta var. contorta, P. kesiya var. kesiya, P. maximinoi, P. mugo subsp. rotundata, P. mugo subsp. uncinata, P. peuce, P. sylvestris . var mongolica, P.tecunumanii HOSTS (D. septosporum)
21. 24/04/2015 21 • Seven other known susceptible conifers • Larix decidua • Picea abies • Picea omorika • Picea pungens • Picea sitchensis • Picea shrenkiana • Pseudotsuga menziesii • The known natural host range of Dothistroma pini is primarily sub-species of Pinus nigra (France, Hungary, Russia, USA - Michigan, Minnesota, and Nebraska) and Pinus mugo has also been recorded as a host in Russia. HOSTS
22. 24/04/2015 22 Pinus nigra var laricio Hosts and impact
23. 24/04/2015 23 Pinus nigra var laricio Hosts and impact
24. 24/04/2015 24 Pinus contorta ssp. latifolia Hosts and impact
25. 24/04/2015 25 Pinus contorta ssp. latifolia Hosts and impact
26. 24/04/2015 26 Pinus sylvestris Hosts and impact
27. 24/04/2015 27 Picea pungens Pinus cembra Hosts and impact
28. 24/04/2015 28 Picea abies Hosts and impact
29. 24/04/2015 29 Picea schrenkiana in CZ 2006 2007 Hosts and impact
30. 24/04/2015 30 • Loss in yield due to needle necrosis and premature defoliation leading to loss of subsequent photosynthetic ability. • Young trees ca. <10 years • all needles equally efficient thus a liner relationship between infection and growth • Greatest reduction seen in height increment • Older trees • If infection is low, little impact as older needles (which are infected first) are less efficient • If infection >25%, greatest reduction in diameter increment • If infection 75% or >, diameter growth practically ceases Impact – yield
31. 0 0.005 0.01 0.015 0.02 0.025 0.03 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 Tree Age Annual Volume Increment Disease impact
32. 24/04/2015 32 • Mortality seen if infection levels are high for successive years - • 10-38% in two years in P. flexilis stands, Montana, USA • 60% in three years in P. radiata stands, Canada • 68% in two years in P. radiata stands, California, USA • Over 90% in P. ponderosa stands, Illinois, USA • 6% per annum in P. nigra subsp. laricio, and 20% per annum in P. contorta var. latifolia in UK • In NZ annual timber losses (mainly from loss in yield) is between ca. 20 and 25 million NZ$ despite control measures. • In the UK it was estimated as ca. £8million/annum Impact – mortality
33. Mortality: DNB + insect impact
34. 24/04/2015 34 Control - silviculture • Thinning and pruning reduces infection levels • increases air circulation • decreases humidity • decrease needle drying time and thus infection • removes infected material • And, for thinning, increases the distance between trees and thus the effectiveness of rain splashed spores • Pruning • In NZ, reduced infection levels for 2 to 5 years • Thinning • In UK, infection halved following heavy thinning but little impact after 4-5 years.
35. Control: Species/provenance change • Some disease resistance reported within species • Varieties of P. nigra from Serbia and Bosnia Herzegovina and P. ponderosa from the Rocky Mountains • P. radiata breeding programme in New Zealand • Families and hybrids of radiata pine that incorporate Dothistroma resistance predicted to have a 12% reduction in crown infection • Two students are currently looking at the genetic and phenotypic variability in populations of SP and LP • Initial results suggest that some populations of SP may be more susceptible than others.
36. 24/04/2015 36 Control – Resistance and breeding • P. radiata breeding programme in New Zealand • Families and hybrids of radiata pine that incorporate Dothistroma resistance predicted to have a 12% reduction in crown infection • Dothistroma resistance is a moderately heritable and is a quantative trait and therefore can collect seed from resistant clones. Some disease resistance between provenances: Inland (dead!!) versus Coastal and Alaskan lodgepole pine (alive)
37. Chemical control In New Zealand Copper applied routinely via aerial applications (up to 200 tonnes/annum) - generally once every 3-5 years - suppresses the disease –not a “cure” Scotland (UK) 2013…..
38. Summary We’ve covered: •Dothistroma history and distribution •Infection process/ symptom development •Hosts affected • appearance of symptoms • impact •Management Now it’s your turn! You can help manage the disease by monitoring species distribution, mating type distribution and levels of variation across Europe… ENJOY THE COURSE! 24/04/2015 38
39. 24/04/2015 39
40. 1. Climatic conditions Increase in frequency of days where temperature => 18-20˚C with 3d rain + 0 1 2 3 4 5 6 7 70s 80s 90s 00s (00-05) Frequency Why now?
41. 3. Plant Trade -regular outbreaks since 2005 in GB -General increase in introduction of exotics Why now? 2. Species composition • Large areas of single species • Reliance on a low number of species
42. Management - silviculture • Twelve 6 hectare stands of CP (total 72ha) each split in to 2ha treatment plots • Different levels of infection by DNB • Planting year 1982 or 1983 and YC 14-16 i.e. time of 1st thin • First thin 2004/5, second thin 2009/11
43. Management - silviculture