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How to Manage Vascular Bacterial Infections

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Pierce’s disease, bacterial canker, citrus greening, crown gall, and many other diseases share a common mechanism. Each is caused by bacterial populations plugging the plant’s vascular tissue, preventing transport of nutrients and water in the plant.

Fields where vascular bacterial diseases become established often have similar environmental and nutritional characteristics. Emerging research describes how these organisms thrive in environments where manganese availability is very low, as a result of chelation or soil oxidation, and where plant sap accumulates elevated ammonium as a result of photorespiration with inadequate carbohydrate reserves.

By understanding the root causes of these diseases we can begin correcting nutrition imbalances and cultural practices to increase resistance and reduce severity. In this webinar, John Kempf describes how to prevent vascular bacterial diseases with organic practices. Watch the video at https://youtu.be/oDumwyNE0CI.

Publié dans : Sciences
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How to Manage Vascular Bacterial Infections

  1. 1. MANAGING VASCULAR BACTERIAL INFECTIONS A Webinar Hosted by AEA Featuring John Kempf
  2. 2. Pathogens in focus: Xylella Fastidiosa - Pierce’s disease and many others Pseudomonas syringae - bacterial canker Agrobacterium tumefaciens - crown gall Candidatus Liberibacter asiaticus - citrus greening
  3. 3. New insights into historical science
  4. 4. Insects are nature’s garbage collectors, diseases are her cleanup crew. ~William Albrecht
  5. 5. Plants have the capacity to be completely immune to disease, when supported with the necessary nutrition and microbiome.
  6. 6. There can be two types of immunity: ‘Passive immunity’ where the plant does not provide the nutrition and/or environment for the potential pathogen. ‘Active immunity’ where the plant actively produces immune compounds from the ISR or SAR pathway.
  7. 7. Before
  8. 8. After
  9. 9. Here you can see Mike standing in front of these trees, holding a poster showing what they looked like three years prior. The yield increased to 8 tons per acre up from 2 tons per acre.
  10. 10. Bacterial Canker Videos
  11. 11. Orchard Under AEA Program Management Video
  12. 12. How can we measure and manage the nutritional and environmental status within the plant?
  13. 13. Eh - pH and Plant Health Validation of old work by Louis-Claude Vincent (Vincent’s Bioelectronic: Eh, pH, resistivity as indicator of human health) by recent researches: virus (alkaline-oxidized), fungi (acidic- oxidized), etc. Change in perspective: ● Plants are not necessarily a resource for their bio-aggressors (pests and diseases): they are so only when they are imbalanced, especially regarding Eh-pH-EC ● We can, through agricultural practices, cropping systems, and nutrition management modify these bio-physico-chemical conditions in soil and plants to make them unfavorable for bio-aggressors ● Agro-ecological crop protection, prophylaxy
  14. 14. Eh - pH and Plant Health
  15. 15. Learn about eH on the Regen.Ag Academy
  16. 16. Plasmopara viticola Proteobacterium (gram-) Biotrophic Xylella fastidiosa Pierce's disease Penetration by xylem sucking vector insects: leafhoppers (Homalodisca), cercopes Plant response: Thyllose and gums, AND Location: Xylem only (biofilm that blocks circulation) Favored by: Heat, pH 6.5 - 6.9 Treatment: Bacteriophage test, natural antibiotics Virulence: Polygalacturonase (digests pectin) Prevention: Variety selection, vector control Eh-pH and Plant Health in Vines
  17. 17. High soil temperatures Dry soil conditions Aerobic soils dominated by aerobic bacteria These oxidizing factors should be counterbalanced with cultural management practices. Oxidizing Environmental Factors
  18. 18. Instead, we often add even more oxidizing factors to the soil environment: Bare soil High EC ‘salt’ fertilizers Limestone Nitrate nitrogen Glyphosate
  19. 19. Nitrate - NO3 = oxidized Ammonium - NH4 = reduced
  20. 20. Manganese Principally absorbed in the reduced form. Generally poorly available in oxidized soils, or soils dominated by aerobic ‘oxidizing’ microbial communities.
  21. 21. The survival, germination, growth, and variants of pathogens may be influenced by the amount and form of Nitrogen... Nitrogen may affect the virulence of a pathogen by stimulating or inhibiting enzymes synthesis or activity required for pathogenesis… Datnoff, L. E., Elmer, W. H., Huber, D. M. & Others. Mineral nutrition and plant disease. (American Phytopathological Society (APS Press), 2007).
  22. 22. Pierce’s Disease (Xylella Fastidiosa) An application of the strategy is a novel method of control of citrus variegated chlorosis, caused by Xylella fastidiosa. In this system a Brachiaria species, a grass that inhibits nitrification, is grown between the rows of citrus. It is optimally fertilized, mowed twice a year, under the citrus trees to provide weed control and nutrients as the mulch mineralizes. With nitrification inhibited, it provides only NH4 as an N source for the Citrus and increases Mn uptake by 50% so that the disease is suppressed and overall tree growth and productivity are enhanced. (Wells et al, 1995, T. Yamada, Potafos, Piracicaba, Sao Paolo, Brazil personal communication 2003)1 1. Datnoff, L. E., Elmer, W. H., Huber, D. M. & Others. Mineral nutrition and plant disease. (American Phytopathological Society (APS Press), 2007).
  23. 23. Crown Gall Agrobacterium tumefaciens The addition of glycine to Agrobacterium tumefaciens increased the pathogenicity and virulence of this bacterium.1 Abundant levels of oxidized iron are known to stimulate Agrobacterium tumefaciens. 2 1. Rubio-Huertos, M. & Beltra, R. [Fixed L-forms of Agro-bacterium tumefaciens obtained by means of glycocoll]. Microbiol. Esp. 15, 219–230 (1962) 2. Leong, S. A. & Neilands, J. B. Relationship of siderophore-mediated iron assimilation to virulence in crown gall disease. J. Bacteriol. 147, 482–491 (1981)
  24. 24. If you want to solve these problems, or get more information: Call AEA 800-495-6603