ASSESSMENT OF DISINFECTANTS FOR CONTROL OF
PHYTOPHTHORA RAMORUM
Assessment of disinfectants for control of
Phytophthora ramorum
Heather Hammack, M.S.
Graduate Research Assistant

Steven ...
Assessment of disinfectants for control
of Phytophthora ramorum
• Collaborative project between:
– CSU Agricultural Experi...
Team
•
•
•
•
•
•

Steven E. Newman – co-principal investigator
Craig Ramsey – co-principal investigator
Heather Hammack – ...
Goals of this project
• Test oxidant disinfectants for decontamination of
greenhouse supplies, contaminated soil, and infe...
Phytophthora ramorum
• Sudden oak death carried by (P. ramorum) is a
fungal pathogen that infects over 120 plant hosts
and...
Phytophthora ramorum
• Spore structures from this pathogen can survive
in water and soil, which allows them to be widely
d...
From:
Scott Pfister, Director
Forest Pest Programs
USDA APHIS PPQ
From:
Scott Pfister, Director
Forest Pest Programs
USDA APHIS PPQ
Disinfection
Common industrial oxidizers and their potential relative to chlorine
Oxidant

Oxidation potential
(mV)

Oxida...
Disinfection
Pathogen survival from laboratory simulations and
hydrocooler studies according to Suslow (2003)
Survival at ...
Lang, J. M., Rebits, B., Newman, S.
E., and Tisserat, N. 2008.
Monitoring mortality of Pythium
zoospores in chlorinated wa...
Heather Hammack’s
MS Thesis Research
Objectives
• Evaluate Camellia japonica ‘Scentsation’
foliage response sprayed with chlorine dioxide
solution at three dif...
Objectives
 Determine the impact of five consecutive
spray applications on the photosynthetic plant
health of Camellia ja...
Objectives
 Assess Camellia japonica ‘Scentsation’ plant
marketability after spray applications using a
visual injury rat...
Methods
 Two oxidants:
 chlorine dioxide (ClO2) at three rates 0, 100, 200,
and 400 ppm – Electro-Biocide: Strategic
Res...
Methods
Visual assessments:
 Three days after each of the five successive spray
applications
 Six and 14 days following ...
Methods
Chlorophyll Fluorescence
 Dark-adapted fluorescent measurements (Fv/Fm)
measured with a LI-COR 6400XT Portable
Ph...
Common Visual Injuries to
Camellia Foliage
• Necrotic lesions on leaf tips
• Necrotic lesions on leaf
margins
• Necrotic f...
Threshold of Marketability
<3-6% MTR
(not damaged)
Oxidant

>3-6% MTR
(damaged)

Rate (ppm)

Visual Analysis No.

Rate (pp...
Conclusions
 Changes in camellia foliage chlorophyll
fluorescence (Fv/Fm) in response to oxidant
applications occurs thre...
Conclusions
 Sarcosinate surfactant increases Fv/Fm with
increasing oxidant concentration
 Electro-BioCide has a positiv...
Contact Information
• Review and share this presentation:
http://www.slideshare.net/snewman7118
• Website:
http://www.gree...
Assessment of disinfectants for control of Phytophthora ramorum
Assessment of disinfectants for control of Phytophthora ramorum
Assessment of disinfectants for control of Phytophthora ramorum
Assessment of disinfectants for control of Phytophthora ramorum
Assessment of disinfectants for control of Phytophthora ramorum
Assessment of disinfectants for control of Phytophthora ramorum
Assessment of disinfectants for control of Phytophthora ramorum
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Assessment of disinfectants for control of Phytophthora ramorum

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Presentation delivered as part of the Colorado State University Research Updates at the ProGreenEXPO in Denver, CO 12 February 2014.

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Assessment of disinfectants for control of Phytophthora ramorum

  1. 1. ASSESSMENT OF DISINFECTANTS FOR CONTROL OF PHYTOPHTHORA RAMORUM
  2. 2. Assessment of disinfectants for control of Phytophthora ramorum Heather Hammack, M.S. Graduate Research Assistant Steven E Newman, Ph.D. Greenhouse Crops Extension Specialist and Professor of Floriculture Craig Ramsey, Ph.D. USDA-APHIS-PPQ-CPHST ProGreen EXPO 11 February 2014
  3. 3. Assessment of disinfectants for control of Phytophthora ramorum • Collaborative project between: – CSU Agricultural Experiment Station – USDA-APHIS Center for Plant Health Science and Technology
  4. 4. Team • • • • • • Steven E. Newman – co-principal investigator Craig Ramsey – co-principal investigator Heather Hammack – MS horticulture student Vanessa Sandoval – MS horticulture student Debra Newman – research associate Paul Freebury – research associate
  5. 5. Goals of this project • Test oxidant disinfectants for decontamination of greenhouse supplies, contaminated soil, and infected plants that are contaminated with a fungal surrogate for P. ramorum. • The main objectives of this project are to determine: – efficacy of oxidants on greenhouse supplies and equipment, – decontamination of greenhouse soil, and – phytotoxicity of oxidants to selected nursery plants.
  6. 6. Phytophthora ramorum • Sudden oak death carried by (P. ramorum) is a fungal pathogen that infects over 120 plant hosts and is threatening shrub propagation in many U.S. nurseries. • Oomyctes in the genus Phytophthora are the most destructive plant pathogens in agricultural and nursery production today.
  7. 7. Phytophthora ramorum • Spore structures from this pathogen can survive in water and soil, which allows them to be widely dispersed by natural causes and by national transportation networks. • Inorganic disinfectants based on oxidant chemistry have a low risk of inducing microbial resistance due to their multi-site, mode of action.
  8. 8. From: Scott Pfister, Director Forest Pest Programs USDA APHIS PPQ
  9. 9. From: Scott Pfister, Director Forest Pest Programs USDA APHIS PPQ
  10. 10. Disinfection Common industrial oxidizers and their potential relative to chlorine Oxidant Oxidation potential (mV) Oxidation relative to chlorine Fluorine 3,050 2.25 Ozone 2,070 1.52 Hydrogen peroxide 1,780 1.31 Potassium permanganate 1,680 1.25 Chlorine dioxide 1,570 1.15 Chlorine 1,360 1.00 Bromine 1,070 0.70
  11. 11. Disinfection Pathogen survival from laboratory simulations and hydrocooler studies according to Suslow (2003) Survival at ORP (mV) Pathogen < 485 550<X<620 >665 E. coli O157:H7 > 300 s < 60 s < 10 s Salmonella spp. > 300 s > 300 s < 20 s L. monocytogenes > 300 s > 300 s < 20 s Thermotolerant coliform > 48 hr > 48 hr < 30 s
  12. 12. Lang, J. M., Rebits, B., Newman, S. E., and Tisserat, N. 2008. Monitoring mortality of Pythium zoospores in chlorinated water using oxidation reduction potential. Online. Plant Health Progress doi:10.1094/PHP2008-0922-01-RS.
  13. 13. Heather Hammack’s MS Thesis Research
  14. 14. Objectives • Evaluate Camellia japonica ‘Scentsation’ foliage response sprayed with chlorine dioxide solution at three different concentrations, with and without the surfactant Sarcosinate, with a negatively charged electrostatic low volume sprayer.
  15. 15. Objectives  Determine the impact of five consecutive spray applications on the photosynthetic plant health of Camellia japonica ‘Scentsation’ and maximum quantum efficiency fluorescence analysis (Fv/Fm)
  16. 16. Objectives  Assess Camellia japonica ‘Scentsation’ plant marketability after spray applications using a visual injury rating scale
  17. 17. Methods  Two oxidants:  chlorine dioxide (ClO2) at three rates 0, 100, 200, and 400 ppm – Electro-Biocide: Strategic Resource Optimization, Inc.  hydrogen dioxide (H2O2) at two rates, 0 and 100 ppm – OxiDate 2.0: BioSafe Systems, Inc.  Two surfactant rates – 0 and 0.2% sarcosinate  Five foliar application dates at three-day intervals
  18. 18. Methods Visual assessments:  Three days after each of the five successive spray applications  Six and 14 days following the final spray application
  19. 19. Methods Chlorophyll Fluorescence  Dark-adapted fluorescent measurements (Fv/Fm) measured with a LI-COR 6400XT Portable Photosynthesis and Fluorescence System  day following each disinfectant spray application  four and seven days following final spray application
  20. 20. Common Visual Injuries to Camellia Foliage • Necrotic lesions on leaf tips • Necrotic lesions on leaf margins • Necrotic foliage spotting
  21. 21. Threshold of Marketability <3-6% MTR (not damaged) Oxidant >3-6% MTR (damaged) Rate (ppm) Visual Analysis No. Rate (ppm) Visual Analysis No. Chlorine Dioxide 0 7 0 Chlorine Dioxide 0 + SARC 7 0 + SARC Chlorine Dioxide 100 7 100 Chlorine Dioxide 200 6 200 7 Chlorine Dioxide 400 3 400 4 Chlorine Dioxide 100 + SARC 6 100 + SARC 7 Chlorine Dioxide 200 + SARC 4 200 + SARC 5 Chlorine Dioxide 400 + SARC 3 400 + SARC 4 Hydrogen Dioxide 100 7 100 Hydrogen Dioxide 100 + SARC 7 100 + SARC
  22. 22. Conclusions  Changes in camellia foliage chlorophyll fluorescence (Fv/Fm) in response to oxidant applications occurs three days earlier than visual symptoms  Electro-BioCide applied at a rate predicted to eradicate Phytophthora ramorum (200 mg·L-1) will not visually damage plants until after five consecutive spray applications
  23. 23. Conclusions  Sarcosinate surfactant increases Fv/Fm with increasing oxidant concentration  Electro-BioCide has a positive effect on photosynthetic functioning over time
  24. 24. Contact Information • Review and share this presentation: http://www.slideshare.net/snewman7118 • Website: http://www.greenhouse.colostate.edu • eMail: Steven.Newman@Colostate.edu

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