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.

1. MANAGING VASCULAR BACTERIAL INFECTIONS
A Webinar Hosted by AEA Featuring John Kempf

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. New insights into historical science

4. Insects are nature’s garbage collectors,
diseases are her cleanup crew.
~William Albrecht

5. Plants have the capacity to be completely
immune to disease, when supported with
the necessary nutrition and microbiome.

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. Before

8. After

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. Bacterial Canker Videos

11. Orchard Under AEA Program
Management Video

12. How can we measure and manage the
nutritional and environmental status within
the plant?

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. Eh - pH and Plant Health

15. Learn about eH on the Regen.Ag
Academy

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. 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. Instead, we often add even more oxidizing
factors to the soil environment:
Bare soil
High EC ‘salt’ fertilizers
Limestone
Nitrate nitrogen
Glyphosate

19. Nitrate - NO3 = oxidized
Ammonium - NH4 = reduced

20. Manganese
Principally absorbed in the reduced form.
Generally poorly available in oxidized soils,
or soils dominated by aerobic ‘oxidizing’
microbial communities.

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. 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. 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. If you want to solve these
problems, or get more
information:
Call AEA
800-495-6603