ipm approaches for phytophthora root and crown … green-ipm... • use of infested water for...

IPM Approaches for Phytophthora Root and Crown

Rot of Small Fruit Nursery Stock Dr. Johanna Del Castillo-Múnera

Dr. Cassandra Swett, Small Fruit and Grape Pathology Lab

University of Maryland, College Park

Chesapeake Green 2016

[email protected]

Outline

• Phytophthora root rot in Blueberries

• Phytophthora root rot in raspberries

• Phytophthora root rot in stone fruits

• Water molds

• A system approach to manage diseases

• Chemical control

• Fungicide resistance

• Conclusions

Water molds : Oomycetes

• Phytophthora is a water mold• It looks like a fungus but is not• More closely related to brown

algae than to fungi

Phytophthora cinnamomi (Leon, 2015)

They like Water!!

• Propagation: swimming and reproducing in water.

(Brooks, 2016)

Why do we care about Phytophthora ?

1. Quality issue

Plant stress after sale causes the disease to develop from undetected infection:• Drought (Retail store)• Saturated soils (standing water)

Start exhibiting disease symptoms

Asymptomatic infected plants-Look healthy, die after sale


1. Quality issue, cont…

Detection of P. ramorum will result in quarantine

Asymptomatic plants can harbor quarantined pathogens--Ex: P. ramorum = regulatory issue


2. Yield loss

3. Source of inoculum-spore from diseased plants get into

water

Infected plants die in the nursery

There is no cure for infected plants

Phytophthora root rot in blueberries

• Symptoms:

• Chlorosis

• Wilting and stunting

• Causal agent: Phytophthora cinnamomi

Jeffrey G. Williamson



• Symptoms:

• Chlorosis


• Reddish-brown discoloration of

Wood at soil line

• Reduced root system



• Symptoms:

• Chlorosis


• Reddish-brown discoloration of

Wood at soil line

• Reduced root system

• Brownish Feeder roots

• Disease occur in patches(Serdani, 2011)

Use of tolerant cultivars (Blueberries)

Tolerant Susceptible

Legacy Duke

Liberty Draper

Aurora Bluetta

Overtime Blue Ribbon

Reka Cargo

Clockwork Last Call

Bluecrop Top Shelfhttp://www.fallcreeknursery.com/commercial/variety/commercial_northern-highbush

Phytophthora root rot in Raspberries

• Symptoms: • Chlorosis of canes

• Wilting

• Number of emerging primocanes is reduced

• Leaves turn yellow, wilt, and scorch (WSU extension, 2016)

Causal agent: Phytophthora rubi, P. megasperma, P. cactorum, P. citricola, P. cryptogea.

Phytophthora root rot in Raspberries

• Causal agent: Phytophthora spp.

• Symptoms:

• Dark water-soaked lesion at the base

(PNWEP, 2011)

• Reddish brown discolorationof infected root.

(Porter, 2013)

Use of tolerant cultivars (Raspberries)

Very Resistant Moderate Resistant

Susceptible Very susceptible

Cascade Bounty

Chilliwack Amity Anne

Cascade delight

Fairview Caroline Canby

Josephine Chilcotin Chemainus

Polka Haida Heritage

Wakefield Meeker

Nootka

Rudi

Willamette

Jewel

Munger

http://sweetmansgeneralstore.com/product/heritage-red-raspberry-bareroot/

Phytophthora on stone fruits : apple, cherry, plums

• Causal agent: Phytophthora spp.

• Symptoms:

• Slow or poor growth

• Wilting, purple coloration in the foliage

(Thomson, 2000)

Phytophthora on stone fruits : apple, cherry, plums • Causal agent: Phytophthora spp.

• Symptoms:

• Slow or poor growth

• Wilting, purple coloration in the foliage

• Brownish discoloration of the crown and roots

• Decline and collapse

(Pscheidt et al. 2016)

Use of tolerant cultivars stone fruits

https://www.flickr.com/photos/jmcextman/5373033011

Apple Plums Cherry

M.9 Relatively resistant

Mazzard

M.2 Morello

M.4 Colt

http://blog.banggood.com/how-to-grow-cherry-tree-form-seed-26377.htmlhttp://www.dreamstime.com/photos-images/plums-tree-detail.html

Diagnostic

https://extension.umd.edu/plantdiagnosticlab

How to submit samples?

• Fresh plant material (not entirely dead plants!)

• Wrap samples in paper towels Do NOT add moisture

• Mail samples in a sturdy container: Boxes, not bags

• Include pictures of the disease stages

• When possible send the entire plant

(Photo credit:NDSU Plant diagnostic lab)

What conditions favor the disease?

• Poorly drained or wet soils favor the pathogen.

http://www.boldsky.com/home-n-garden/gardening/2015/gardening-tips-for-wet-soil-066015.html

• Use of infested water for irrigation

• Ground to pot contact.


https://aijoubonsai.wordpress.com/category/bonsai-progressions/

http://www.planetnatural.com/potting-mix-recipes/

• Ground to media contact.

• Contaminated pots from previous years.


• Infected new plant material.

http://stevespeonygarden.blogspot.com/2011/04/over-view-of-blueberries.html

How does the disease develop?

Produced under high soil moisture.Temp: 68-900F

Overwinter structures: Survive many years in the soil

(DPIPWE, 2015)

How does the disease develop?

Produced under high soil moisture.Temp: 68-900F

Overwinter structures: Survive many years in the soil

(DPIPWE, 2015)

Winter

A system approach for disease management

• Integrates different risk management measures.

• How different components of a whole can influence each other.

• Overlapping and cumulative preventive measures.

Wellness program Vs. Emergency room

In Nurseries:• Prevent the need to respond with a spray

program• Crop destruction• Quarantine

http://www1.umn.edu/ohr/prod/groups/

http://www.shutterstock.com/pic-185350787/stock-vector-sick-cartoon-man-visiting-the-doctor.html

HACCP: Hazard Analysis of Critical Control Points • Risk management program:

• Identify the hazards

• Evaluate and correct the critical points of contamination.

• Widely used in the food system.

• Key points: Identify critical control points (CCP) and Hazards.

Hazards:1. New plants2. Contaminated ground3. Contaminated irrigation

water 4. Used containers5. Contaminated potted media

How can we control these hazards?

(Parke & Grünwald, 2012)

1. New plant material

CCP• Arrival of new plant material

Management practice

• Scout new material incoming to the greenhouse.

• Reject loads with infected plant material.

• Place in quarantine new plant material. (60 days from arrival)

• Do not mix new plant material with existing stock, until you are confident thenew ones are pest-free.

• Buy plants from certified nurseries.

2. Contaminated ground CCP

• Direct contact between soil and containers.

Management practice • Raise containers, add a gravel or

rock barrier between them.


2. Contaminated ground cont. CCP

• Splash dispersal of pathogens from contaminated ground.

(Parke, 2014)

2. Contaminated ground cont. CCP

• Splash dispersal of pathogens from contaminated ground.

Management practice • Prevent standing water, avoid

overwatering, improve drainage.

(Parke, 2014) (Griesbach,2012)

2. Contaminated ground cont. CCP• Movement of contaminated soil

(tools, equipment, staff)

Management practice • Clean equipment (shovels, shoes)

and vehicles after working in contaminated areas.

http://www.jeepyurongfu.com/45849001-how-to-clean-plant-containers/https://gardeninglandscaping.wordpress.com/2008/06/04/gardening-tools/

2. Contaminated ground cont.

CCP• Contamination of soil by

infested foliage.

Management practice

• Prevent and remove leafy debris from accumulating on the soil.

http://ccber.ucsb.edu/ecosystem-management/greenhouse-and-nurseryhttp://gardenrant.com/2014/11/piling-leaves-and-stacking-functions.html

3. Contaminated irrigation water

CCP

• Use of contaminated water as irrigation source (pond, river, recycled water).

Management practice • Use water from wells or municipal sources,

disinfest irrigation water.

• Test water for Phytophthora

• Contact Phytophthora testing lab: Ristaino lab NCSU

https://ristainolab.cals.ncsu.edu/teaching/phythophthora-diagnostics/

1. Filter• Slow sand filtration

• Effective at controlling Phytophthora

• Filter maintenance : Cleaning filter’s surface to avoid clogging.

biofilm (accumulation of microorganisms and organic matter)

3. Contaminated irrigation water cont.

Water disinfecting methods

http://www.oasisfilter.com/operation.htm

http://www.shubhaminc.com/multigrade-sand-filter--1603617.html

2. Disinfest • Each nursery facility selects the best disinfestation method.

• Learn more about water treatment Methods:

http://www.watereducationalliance.org/education.asp


Water disinfecting methods

Treatment Ingredient Effect Concentration

Chlorine Calcium hypocloriteSodium hypocloriteChlorine gas

Oxidize agents changed chemical structure of organic matter and may kill pathogens.

0.5-2 ppm free chlorine

Copper ionization Cu++ Cu ions are toxic to Phytophthora and Pythium

0.5 to 1 ppm CU

Heat Kill plant pathogens 203 °F for 30 S.

http://www.watereducationalliance.org/education.asp


CCP• Splash dispersal of pathogens

• Contamination of waterways

Management practice


• Prevent standing water: well drainage, avoid over irrigation, raising containers off the ground.

• Schedule watering in the morning.

• Collect runoff water and disinfested it.

Research project: can reduced irrigation water prevent root rot diseases?

• Can a deficit irrigation system prevent pathogen spread in water and suppress infections?

• Study the development of plant diseases, pathogen infection and plant health under a deficit irrigation water treatment.

Photo credit: SCRI- CLEAN WATER3

4. Used containers

CCP• Re use of infested containers

Management practice

• Disinfesting options:• Heat: 30 min exposure to moist

heat will kill :

Pythium and Phytophthora

Fungi and bacteria

110

120

150

160

°F


• Use of new containers, or disinfest used containers

4. Used containers cont.

Container disinfecting methods

• Aerated steam. at 140°F for 30 min. Most pathogenic microorganism will be killed.

• Hot water dip. Submerge containers in hot water (180°F for 30 min).

• Disinfectants. • Peroxide (ZeroTol, OxiDate)

• Bleach

• Quaternary ammonium (Physan 20, Green-Shield CA)


Fungi and bacteria

110

120

150

160

°F

5. Contaminated potted media

• Use of contaminated mediaCCP Management practice


• Store media in an area free of contamination: away of infested water, soil, plant.

• Use clean equipment to mix planting media.

• Use media free of Phytophthora spp., disinfest ingredients before use, use “certified media” Ask supplier.

5. Contaminated potted media cont.

• Use aerated steam: Mix ingredients, place them in a steam chamber for 30 min, at 140°F.

• Composting of used media: Compost the materials keeping high temperature (140°F) during 15-25 days.

If you mix your own potting media:


Fungi and bacteria

110

120

150

160

°F

http://ccber.ucsb.edu/ecosystem-management/greenhouse-and-nursery

http://sanc.nationalplantboard.org/

Chemical control

Fungicide Active Ingredient Fungicide group

Rate (per/100 gallon)

Frequency (days)

Subdue maxx Mefenoxam 4 1-2 fl oz 30-60

Aliette Fosetyl-Al 33 2.5 lb 30

Agri-Fos Phosphorous acid

33 1-3 quarts 30

Disarm-O Fluoxastrobin 11 0.15-0.6 fl oz 14-28

Orvego Dimethomorph+ ametoctadine

4540

11-14 fl-oz 14

Development of resistance

• Systemic Fungicides (SF) have a specific target in the microorganisms. As a response microorganism can change this target region or create mechanisms to “avoid” the fungicide action.

Before SF After 1st SF application

After 2nd SF application

After 3rd SF application

Fungicide rotation is important for avoiding or delaying fungicide resistance!!

Between application

Phytophthora spp. n SensitivityMefenoxam (100

µg/mL)

P. cinnamomi 77 Sensitive 17

Intermediate 57

Insensitive 3

P. citrophthora 23 Sensitive 10

Intermediate 13

Insensitive none

P. multivora 15 Sensitive 4

Intermediate 9

Insensitive 2

P. pini 21 Sensitive none

Intermediate 21

Insensitive none

P. plurivora 107 Sensitive 10

Intermediate 84

Insensitive 13

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

1 9

17

25

33

41

49

57

65

73

81

89

97

10

5

11

3

12

1

12

9

13

7

14

5

15

3

16

1

16

9

17

7

18

5

19

3

20

1

20

9

21

7

22

5

23

3

24

1

Ave

rage

Rel

ativ

e G

row

th (

%)

Isolates

Mefenoxam (100 µg/mL)

Evidence of fungicide resistant Phytophthoraisolates from Maryland Nurseries (Beaulieu,2015)

Phytophthoraspp.

n SensitivityMefenoxam(200 ug/mL)

Fosetyl-Al(500 ug/mL)

Fluoxastrobin(200 ug/mL)

Dimethomorph(400 ug/mL)

Dimethomorph + Ametoctradin

(100 ug/mL)

P. cinnamomi 3 Sensitive 3 3Intermediate

Insensitive 3 3 3

P. multivora 2 Sensitive 2 2

Intermediate

Insensitive 2 2 2

P. plurivora 13 Sensitive 11 11

Intermediate

Insensitive 13 13 13 2 2

Evidence of fungicide resistant Phytophthoraisolates from Maryland Nurseries (Beaulieu,2015)

Conclusions

• Phytophthora root rot diseases can be controlled by implementing preventive measures in nursery facilities during the entire crop cycle.

• Water is a CCP for disease management: Wet soils favor the spread and development of the disease. An adequate management of water in nurseries is a key point to control and prevent root rot diseases.

• The use of fungicides should be combine with and integrated pest management program.

Resources

• Griesbach, J. A., Parke, J. L., Chastagner, G. C., Grunwald, N. J., and Aguirre, J. 2012. Safe procurement and production manual: A systems approach for the production of healthy nursery stock. 2nd ed. Oregon Association of Nurseries, Wilsonville, OR. http://oan.org/associations/4440/files/ pdf/SafeProduction.pdf

• Pscheidt, J.W., and Ocamb, C.M. (Senior Eds.). 2016. Pacific Northwest Plant Disease Management Handbook. Oregon State University. http://pnwhandbooks.org/plantdisease/node/2951/print

• Schilder A., 2015. Excessive rain promotes Phytophthora diseases in raspberries and strawberries.

http://msue.anr.msu.edu/news/excessive_rain_promotes_phytophthora_diseases_in_raspberries_and_strawberri

• Schilder A., 2010. How to recognize Phytophthora and Pythium root rot in blueberries.

http://msue.anr.msu.edu/news/how_to_recognize_phytophthora_and_pythium_root_rot_in_blueberries

http://pnwhandbooks.org/plantdisease/node/2951/print


References

• Griesbach, J. A., Parke, J. L., Chastagner, G. C., Grunwald, N. J., and Aguirre, J. 2012. Safe procurement and production manual: A systems approach for the production of healthy nursery stock. 2nd ed. Oregon Association of Nurseries, Wilsonville, OR. http://oan.org/associations/4440/files/ pdf/SafeProduction.pdf

• Parke, J. L., & Grünwald, N. J. (2012). A systems approach for management of pests and pathogens of nursery crops. Plant disease, 96(9), 1236-1244.

• Pscheidt, J.W., and Ocamb, C.M. (Senior Eds.). 2016. Pacific Northwest Plant Disease Management Handbook. Oregon State University. http://pnwhandbooks.org/plantdisease/node/2951/print

• Schilder A., 2015. Excessive rain promotes Phytophthora diseases in raspberries and strawberries.

http://msue.anr.msu.edu/news/excessive_rain_promotes_phytophthora_diseases_in_raspberries_and_strawberri

• Schilder A., 2010. How to recognize Phytophthora and Pythium root rot in blueberries.


• Serdani 2011. Blueberry root rot http://pnwhandbooks.org/plantdisease/blueberry-vaccinium-corymbosum-root-rot

• Wilcox W., 1992. Phytophthora root and crown rot http://nysipm.cornell.edu/factsheets/treefruit/diseases/phyt/phyt.asp

• DPIPWE, 2015. Phytophthora root rot. Department of primary industries, parks, water and environment.

http://dpipwe.tas.gov.au/biosecurity/plant-biosecurity/pests-and-diseases/phytophthora

• PNWEP, 2011. Raspberry root rot http://pnwhandbooks.org/plantdisease/raspberry-rubus-spp-root-rot

• WSU extension 2016. Integrated pest management for raspberries http://whatcom.wsu.edu/ipm/manual/rasp/phytophthora.html

http://pnwhandbooks.org/plantdisease/node/2951/print


http://pnwhandbooks.org/plantdisease/blueberry-vaccinium-corymbosum-root-rot

http://nysipm.cornell.edu/factsheets/treefruit/diseases/phyt/phyt.asp

http://dpipwe.tas.gov.au/biosecurity/plant-biosecurity/pests-and-diseases/phytophthora

http://pnwhandbooks.org/plantdisease/raspberry-rubus-spp-root-rot

http://whatcom.wsu.edu/ipm/manual/rasp/phytophthora.html

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