- 1. C pPCrop ProtectionPhytophthora Management in Macadamia6th
International Macadamia Symposium, Brisbane, Australia, 18 20
Sept., Brisbane Australia 18-20 Sept 2012 Dr. F e m i A k i n s a n
m iUniversity of Queensland, [email protected]@uq
edu au WorkingtogetherwiththeQueenslandGovernment
2. THE NUT RUSH Prospecting for Gold 3. NEW 2012 1981 Macadamias
prove a M d i guaranteed goldmine for farmers 4. Prospecting for
Gold 5. THE NUT RUSH Prospecting for GoldIs Phytophthora a major
clog in the wheel? 6. Phytophthora:Phytophthora: Ecology &
DescriptionThere are about 120 Phytophthora speciesThey infect >
3500 p y plant speciesp o Crops Arable and tree crops o Forest
trees o Mangroves o Lifestyle horticulture flowers, trees, etc.
Able to cause large scale devastating diseases 7. Phytophthora in
Macadamia Trunk canker 8. Phytophthora in Macadamia Tree decline 9.
Phytophthora in Macadamia Tree death 10. Phytophthora: Lifecycle
11. Phytophthora: Ecology & Description Thrives in wet
conditions Rapid formation of sporangia Abundant zoospore formation
Rapid life cycle Many alternative hosts y Infects multiple plant
parts 12. Phytophthora in Macadamia P. P capsici : raceme, shoot
and nut bli ht , i ih t d t blight - Hawaii 1975, 1979 P.
tropicalis : Macadamia quick decline (with sap bleeding, frass) --
Hawaii P. palmivora : raceme, new leaf flush and nut blight -
Hawaii 1975, 1979; Costa Rica late 1960s1975 P. cinnamomi : Stem
canker, root rot, tree decline, dieback- South Africa, Hawaii,
Australia, Kenya 13. Phytophthora in MacadamiaPhytophthora
cinnamomi Most widespread Most frequent g Most devastating Multiple
symptoms but similar impact on production 14. Phytophthora
cinnamomi: Impact Over $300 million loss to Australian horticulture
& agriculture $US30 million loss to the US avocado industry 60%
macadamia yield loss in Kenya (Mbaka et sl. 2009) sl 100s of
macadamia trees died in SE Australia (Pegg,1981)( gg, ) 15.
Phytophthora in Macadamia 1. Factors that i fl 1 F tth t influence
di disease severity in macadamiait i d i Rootstock & root
density (Good foundation) Soil fertility Environmental stress:
drought, waterlogged2.2Management of diseases caused by
Phytophthora 16. Phytophthora in MacadamiaGoodG d root system
provides a strong foundation tt idt f d ti Good soilBad soil Ugly
soil U lil 17. Phytophthora in MacadamiaGood root system provides a
strong foundationVerypoorPoor GoodVerygood 18. Good root system
contributes to macadamia resilience to adverse conditions 2010
Courtesy: David & Liz Kirby 19. Good root system contributes to
macadamia resilience to adverse conditions 2011 Courtesy: David
& Liz Kirby 20. Good root system contributes to macadamia
resilience to adverse conditions 2012 Courtesy: David & Liz
Kirby 21. Phytophthora in MacadamiaScion affects rootstock
performance5y=0.1384x+0.0633 R 0 071
R=0.071ating(04)4severityra32Treecanopys100123
45Trunkcankerseverityrating(04)T kkii (0 4) 22. Phytophthora in
MacadamiaEffect on grafted tree @ 3 years after planting: H2
(Hinde) rootstock 3.5 Treated (control) 3.0 Untreated 2.5
40%reduction Tree height (m) ) 2.0 1.5 15h60%reduction60% d ti 1.0
0.5 05 0.0 842816 Cultivar 23. Phytophthora in MacadamiaSoil health
Soil fertility - Pc; + Fertilizer + Pc; + Fertilizer + Pc; -
Fertilizer 24. Phytophthora in MacadamiaManagement of Ph t hthMt f
Phytophthora didiseases Plant disease-free materials: good root
structure Monitor tree health: changes in tree performance symptoms
etcperformance, symptoms, etc. Manage soil health: adequate soil
fertility, structure and biological Apply treatment when disease
conducive conditions prevail for extendedperiod Treat affected
trees appropriately 25. Phytophthora in Macadamiay p Do not treat
plants in the nursery with metalaxyl or phosphonates Disease
Management options Chemical Metalaxyl not effective in badly
damaged trees; resistance Phosphoric acid products Cultural
Resistant rootstocks Natural disease suppression (soil health)
Holistic approach combination of 2 or more cultural,
rootstock,chemical and biological tactics are most effective 26.
Phytophthora in MacadamiaManagement of Phytophthora: Chemical
control1.4y = 0 22ln(x) + 1 010.22ln(x) 1.011.2R = 0.961.0 Mean
disease severity rating y = 1.14 - 0.29ln(x)0.8R = 0.98e0.606 y =
1.21 - 0.43ln(x)R = 0.990.4Potassium phosphonate0.2
Metalaxyl-MUntreated control0.0 Year 1 Year 2Year 3 Year 4
Assessment period 27. Phytophthora in MacadamiaBefore & after
Phosphite treatment p 28. Phytophthora in MacadamiaBefore &
after Phosphite treatment p 29. Phytophthora in MacadamiaDecision
Guide for Application of Phosphite to Control Phytophthora
inMacadamiaApplicationstrategySeveritylevel Description
Applicationmethod ScaleHealthy None0 None(Maintain goodgood
managementpractices)Maintenance LowMedium 1 2 FoliarCurativeHigh3
4Trunk orFoliarRestoration VeryHigh 5 Trunk 30. Phytophthora in
MacadamiaManagement of Phytophthora: Cultural controlDrainage is
the most critical factorInorganic nutrition e.g. Calcium - Can be
li d l h t (gypsum) slow release of C ++ C b applied as sulphate
()l lf Ca - Promotes resistance in roots - Acts as a mild fungicide
- Improves soil drainage ~ aerationO ga c amendments: oody u c (C:N
at os 5 00 ),Organic a e d e ts Woody mulch (C ratios
25-100:1),composts, Chicken and green manure, cover crops - P id a
complex bi l i l suppression and promotes root growth Provides l
biological i dtt th 31. Phytophthora in MacadamiaManagement of
Phytophthora: Resistant rootstock Australian R t t k IA t li
Rootstock Improvement Program tP Evaluate rootstocks originating
from three different ecologicalregions Evaluate both clonal and
seedling rootstocks E l t MEvaluate Macadamia species d i i 32.
Phytophthora in MacadamiaConclusionsC l iHolistic view of disease
control is importantKnow the ecology and biology of the pathogen
waterlogging,droughtKnow your crop agronomy, p y y pg y, physiology
etc. gyEmphasis on sustainable managementReduced reliance on
chemicals 33. Other major diseasesFruit & flower diseaseso Husk
spot; Husk rot; Raceme blight; etc.Emerging and new disease
developmentso Tree diebark ~ Botryosphaeriaceae 34. Husk
spotPseudocercospora macadamiae 35. Husk rot &
AnthracnosePhomopsis sp.; Colletotrichum gloeosporioides 36.
Botryosphaeria tree dieback 37. Floret blight 38.
AcknowledgementsFunding & SupportTeam members &
Contributors - Dr. Bruce Topp - Associate Prof. Andre Drenth- Dr
Ken PeggDr. - Mr. Luke SmithWorkingtogetherwiththe
QueenslandGovernmentPENCITON FARMS
