Tolerance of almond rootstocks to root-knot nematodes Peter Clingeleffer, Norma Morales & Brady Smith (deceased March 2013)

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1 Tolerance of almond rootstocks to root-knot nematodes Peter Clingeleffer, Norma Morales & Brady Smith (deceased March 2013) October 12, 2013 CSIRO PLANT INDUSTRY

2 Aim assess available almond rootstock genotypes (18) for resistance to root-knot nematodes found in Australian orchard soils Why minimise risks associated with rootstock choice in almond orchard redevelopment

3 Rootstock adoption (Brown et al. 2014)

4 Orchard collection and nematode extraction 4

5 Identifying root-knot nematodes in Australia Angle Vale 1 M. javanica Lyndsay Point 1 M. incognita Kingston on Murray Monash 1 Mildura 1 1 M. javanica M. incognita M. javanica M. incognita Winkie 1 Red Cliffs 1 Red Cliffs 2 M. arenaria M. arenaria M. arenaria Tanunda 1M. arenaria Tanunda 2 Carwarp1 M. hapla M. javanica McLaren Vale 1 M. javanica 5

6 Impact of root-knot nematodes on almond rootstocks GF677 nemaguard (Brown et al. 2014)

7 Which little pest is that? M. incognita M. javanica M. arenaria M. hapla Photos: Jonathan Eisenbeck, Nemapix vol.1 (upper); (lower)

8 The Arms Race with Root-Knot Nematodes PCR to determine nematode genus PCR to determine species of Meloidogyne -M. arenaria -M. hapla -M. incognita -M. javanica Genus specific marker Species specific marker

9 Meloidogyne spp, the root-knot nematode Juveniles are free living Mostly parthogenic females Hundreds to thousands per egg mass Juveniles establish feeding sites on root-tips and become sedentary Feeding induces multilnucleate giant cells Females become engorged Galls form, disrupting water and nutrient uptake Plants may be stunted Over time galls may crack open allowing for invasion of secondary pathogens as well as decapitating large section of root system

10 Nematode wrangling

11 Nematode screen

12 Glasshouse nematode screening results M. incognita M. arenaria M. javanica S.A. vines B.Valley vines M.Vale vines Rl almonds Rl-L almonds Rl-W almonds A. Vale Cadaman Hansen Adafuel Bright s Hybrid Cornerstone Felinem Garnem Nemaguard Penta Tetra Viking* Atlas GF GF GF Krymsk Monegro Nickels

13 Summary for almond project large difference in nematode resistance across the rootstocks inconsistent levels of resistance against different rootknot nematodes species Glasshouse screening results have shown:- Consequently:- rootstock choice must account for the rootknot species and potentially (pathotype) found in an orchard site, particularly in replant situations Know your enemy

14 Recommendations- industry Use nematode resistance information in rootstock selection (inclusion in research trials and orchards) Confirm resistance/susceptibility of the rootstocks to root-knot nematodes under field conditions Survey almond orchards to identify the distribution of root-knot nematode species and virulence of isolates Implement a soil sampling to identify root-knot nematode species and numbers prior to orchard development, particularly if redeveloping existing orchards or planting into sites used for horticultural pursuits. Avoid redevelopment of orchards with the same rootstock used in original plantings Consider nematode risks as a biosecurity issue

15 Nematodes a bio-security issue? Implement strategies to minimise the risk of spread of species and isolates with varying virulence Implications for movement of personnel and machinery Implications for management of nursery material hot water treatment? glasshouse vs. field nursery propagation? Implications for replanting Know what nematodes you have (pre-planting surveys)

16 Recommendations- future research Include resistance to root-knot nematodes as a key trait for the selection and development of rootstocks Develop an understanding of the inheritance of resistance to Australian root-knot nematodes in Prunus spp. Develop a rapid screen or molecular markers to identify virulent nematode pathotypes of Meloidogyne spp., particularly M. javanica.

17 Further reading Brown, B., Clingeleffer, P., Morales, M. and Smith, B (dec.) Almond rootstocks and nematodes Australian Nutgrower June 2014 (in press)

18 Acknowledgements Almond Board of Australia Ben Brown- organizing project and material supply Nurseries Gabriel Rivera Hernandez technician and photography