Compost tea: a brewable food web for disease control

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Compost tea a brewable food web for disease
control

• Martha Rosemeyer
• June 25, 2003
• rosemeym_at_evergreen.edu

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Outline

• Background- what is compost tea?
• Organisms involved
• Does it work?
• How does it work?
• Future research
• Resources

Photo Seth Book
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What is compost tea?

• Water extract of compost that is brewed, ie
  fermented (Ingham, E. 2001)
• Specifically the organisms are released from the
  compost and increase in number
• May be given nutrients to further increase
  organisms
• Used for disease control, as well as a plant
  nutrient source

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Not to be confused with

• Manure tea made as a nutrient source

• Plant extracts or herbal teas for disease control
  or plant health, for example biodynamic
  preparations

Photos Eliot Colemans European tour (Diver 2001)
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What does compost tea contain?

• plant nutrients and humic acids
• active bacteria (1 billion to 10 trillion cfu/ml)
• active fungi
• protozoa
• nematodes
• products of microbes that can have antibiotic
  properties

Photo from Compost Food Web slide show
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Why compost tea? Why now?

• Increasing societal concern for health and
  environment and organic production
• Lack of disease control mechanisms for organic
  farmers and gardeners
• Restricting agrochemicals due to recognized
  toxicity, for example FQPA
• Organic farmers need control methods that work
  within a holistic system

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Organic sales increasing at 20 per year
Worldwatch Institute. 2000. Why Poison
Ourselves.
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Used extensively due to perceived benefits

• Homeowners
• Nurseries
• Organic crop growers
• Golf courses
• Organic landscape management
• municipal parks and recreation dept
• BUT LITTLE RESEARCH HAS BEEN DONE

Without tea With Tea
Ingham 2001
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Background

• Since 1920s compost water used to soak seeds for
  nutrients, prevent disease
• Two main approaches
• compost extracts watery fermented compost
  extract steepages non-aerated compost tea
  (Scheuerell and Mahaffee 2002)
• fermented but not aerated, stirred occasionally
• lower costs, lower energy
• much research
• disease control has been documented

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• aerated compost tea
• fermented, aerated
• higher costs, energy
• little research, some disease control reports

Diver 2001
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Benefits of compost tea

• Nutrient application
• Disease control
• Foliar disease
• Root disease
• Inoculation of functioning soil food web

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How to make non-aerobic compost tea

• Mix 14-110 compost to water in an open
  container, stir occasionally
• At least 3 d at 15-25C (50-70 F)

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How to make Aerobic Compost Tea

• Choose compost- well aged
• plant based or worm compost
• In water (remove chlorine from water)
• Add nutrients (optional) like molasses, humic
  acids, kelp
• Aerate and mix solution for 12 - 24 - 48 hours

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Commercial aerobic compost tea brewers

• Soil Soup www.soilsoup.com
• Microb Brewer www.microbbrewer.com
• Growing Solutions www.growingsolutions.com
• Earth Tea Brewer www.composttea.com
• Xtractor www.compara.nl/compost_tea_systems.htm/
  English

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Soil Soup www.soilsoup.com
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Microb Brewerwww. microbbrewer.com
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Growing Solutions www.growingsolutions.com

• bubbling
• aeration

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What happens in the compost tea while brewing?

• ? ?

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TESC Student expts Scott Chichester and Seth
Book

• Changes in compost tea
• during brewing
• Preventing damping off
• of marjoram

Photos Seth Book
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Dissolved Oxygen gt5.5 ppm
ppm
48 hrs
24 hrs
ppm
20 hrs
From Book and Chichester
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pH gt 7.2
C
From Book and Chichester
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Food web concept

• Everything eats, everything excretes, and
  everything is food for something"
• Elaine Ingham, 2001
• A great resource
• SWCS/NRCS,
• Soil Biology Primer

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A functioning food web is desirable in a compost
tea
From Soil Biology Primer
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Most bacteria (99) cannot be cultured

• Direct counts and genetic diversity assessment
• Activity of bacteria important
• Nutrients can help to wake up to active state

A ton of microscopic bacteria may be active in
each acre of soil. Bacteria dot the
surface of strands of fungal hyphae. From
Soil Biology Primer
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Fungus beginning to decompose leaf veins in grass
clippings. Soil Microbiology and Biochemistry
Slide Set. 1976. J.P. Martin, et al.,eds. SSSA,
Madison WI.
From Soil Biology Primer
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Roots of Common Bean (Phaseolus vulgaris) from
Costa Rica
Mycorrhizal fungus stained blue
Non mycorrhizal
Photo Rosemeyer
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Mycorrhizal fungi link root cells to soil
particles. In this photo, sand grains are bound
to a root by hyphae from endophytes (fungi
similar to mycorrhizae), and bypolysaccharides
secreted by the plant and the fungi. Soil Biology
Primer, Credit Jerry Barrow, USDA-ARS Jornada
Experimental Range, Las Cruces, NM. From Soil
Biology Primer
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Actinomycetes, such as this Streptomyces, give
soil and compost its "earthy" smell. Soil
Microbiology and Biochemistry Slide Set. 1976.
J.P. Martin, et al., eds. SSSA, Madison, WI
From Soil Biology Primer
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bacteria
Protozoa Flagellates have one or two flagella
which they use to propel or pull their way
through soil. A flagellum can be seen extending
from the protozoan on the left. The tiny specks
are bacteria. Credit Elaine R. Ingham, Oregon
State University
From Soil Biology Primer
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Protozoa Ciliates are the largest of the
protozoa and the least numerous. They consume up
to ten thousand bacteria per day, and release
plant available nitrogen. Ciliates use the fine
cilia along their bodies like oars to move
rapidly through soil Credit Elaine R. Ingham,
Oregon State University, Corvallis From Soil
Biology Primer

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Interaction
cysts

• Vampyrellidae attack fungus take all of wheat

From Soil Biology Primer
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Most nematodes in the soil are not plant
parasites. Beneficial nematodes help control
disease and cycle nutrients. Credit Elaine R.
Ingham, Oregon State University, Corvallis
From Soil Biology Primer
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Interactions Nematode trapping fungi
From Soil Biology Primer
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Microbes are ancient!

• Responsible for all major processes on earth,
  including decomposition and photosysnthesis and
  nutrient cycling
• Major cycles of Earth could continue without
  plants and animals
• Most are beneficial!

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Video Life in the Soil produced by Sakura
Motion Picture Co., Ltd.and MOAProductions
planned by Nature Farming International Research
Foundation Atami, Japan
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Do we know what the diversity or quantity means
with respect to disease?

• Not entirely
• Most soil organisms are unknown!
• How does microbial diversity transfer to
  increasing function?
• If we are mainly interested in disease prevention
  then do we know what mechanism and whether that
  organism is involved?
• In general more diversity means better change
  that have the appropriate organism

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Minimum standards for compost tea/mL (Ingham 2001)

• 10-150 ?g active bacteria,150-300 ?g total
  bacteria
• 2-10 ?g active fungi, 5-20 total fungi
• 1000 flagellated protozoa
• 1000 amoebae protozoa
• 20-50 ciliates protozoa
• 2-10 beneficial nematodes

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Total population of active microbes

• Bacteria minimum 107-1010 (Scheurell and
  Mahaffee)
• But may not be associated with disease control,
  if appropriate agent not present!

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Does it work?

• NCT- Good evidence under
• certain circumstances
• Much research with
• grey mold
• (Botrytis cineraria)
• Downy mildew of grape
• (Plasmopara viticola)

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Evidence of NCT disease suppression
Diver, 1998
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Is ACT better than NCT?

• Both ferment well-characterized compost in water
  for a period of time, with or without nutrients
• Few studies have actually compared the two
• NCT has been suggested to cause plant problems
  and potentially an environment for human pathogen
  growth (Ingham)
• According to Scheuerell and Mahaffee, there is no
  evidence that phytotoxic symptoms

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Apple scab control using NCT and ACT manure-based
spent mushroom compost (Cronin et al. 1996)

• ACT (7 d) vs. NCT (7d)
• In vitro effect on germination
  of conidia of Venturia inaequalis,
  pathogen of apple scab
• NCT reduced conidia germination, not ACT unless
  let sit for another 7 days

Apple scab on leaf and fruit
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Powdery mildew of rose(Scheurell and Mahaffee
2000)

• Three sources of compost
• ACT commercial preparation vs.
  7-day NCT
• All equal results on powdery mildew of rose
  (Sphaerotheca pannosa) within source of compost
• Authors concluded that source of compost more
  important than ACT or NCT

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Pscheidt and Wittig 1996, Willamette Valley

• ACT used regularly throughout growing season
• No effect on powdery mildew of apple or grape,
  apple scab, pear scab, brown rot of peach, peach
  leaf curl and cherry leaf spot
• Significant reduction of brown rot blossom blight
  of sweet cherry (Monilia laxa)

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Tests for Disease control of ACT
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Disease control with ACTGranatstein 1999

• ACT had effects on yield and disease control
• No effect on early blight of tomato
• lettuce drop incidence decrease in summer not
  spring
• Post harvest rot of blueberries significantly
  reduced, but reduced yields
• Spinach yield decreased, but broccoli spring and
  summer increased
• no general pattern

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Disease control with ACTPresidio golf greens

• Decreased No effect
• Microdochium Anthracnose

Conforti et al. 2002
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Bacterial vs. Fungal dominated teas can be
determined by added nutrients (Ingham 2001)

• Bacterial simple sugars to fulvic acids
• Fungal humic acids
• Have been difficult for some to produce fungal
  dominated teas (Scheuerell and Mahaffee 2002)
• Reports reduction of suppression due to nutrient
  competition?
• Useful to know nutrients that support antagonists

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How might compost teas work?Mechanisms from NCT

• Prevention of pathogen colonization
• due to competition of space or nutrients
• direct destruction of pathogen
• Antibiosis
• Release of antimicrobial compounds
• Induced resistance

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Colonization of phylloplane If 70 of leaf
covered by organisms reduction of disease
(Ingham)

• 60-70 active bacteria and 2-5 active fungi
• Various authors
  Pseudomonads,
  aerobic Bacillus,
  aerobic spore forming
  bacteria with reduction
  in powdery mildew
  of grape

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Predation NCT Fusarium spore rupture

• Root drench for Fusarium diseases of pepper and
  cucumber
• Direct destruction on disease-causing spores

Ascospores of Fusarium solani
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Antibiosis what organisms and metabolites may be
involved?

• Bacteria- Bacillus, Pseudomonas, Serrantia
• Yeast- Sporobolomyces, Cryptococcus
• Fungi- Trichoderma, Gliocladium and Penicillium
• Chemicals involved - phenols, amino acids, low
  molecular weight non-protein (sometimes produced
  by fermentation and other times already within
  compost)

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NCT induced resistance to plant pathogens

• Powdery mildew of cucurbits (Sphaerotheca
  fuliginea)
• NCT changed host response to pathogen
• papillae (bumps)
• necrotic reaction
• leaf toughens
• (lignification)

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Standards for compost tea

• So far only one proposed minimum standards
  (Ingham 2001)
• oxygen concentration remain above 5.5 ppm or 60
  DO but there is disease suppression in NCT
• in vitro pathogen inhibition but question as to
  whether this reflects field conditions
• active bacteria 10-150 µg
• active fungi 2-10 µg
• protozoa and nematodes (for soil application)

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Potential to support human pathogens

• Appears that despite popular conception, ACT can
  support human pathogens if fermented with sugars
  (2 papers)
• If no sugars, including molasses, are used then
  neither ACT and NCT appear to be able to maintain
  human enteric pathogens (Escherigia, Salmonella,
  Shigella, Yersinia) even if contain low levels of
  pathogens
• If use worm compost as source appears that can
  avoid pathogens
• Needs more research

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Summary

• Jury still out on NCT vs ACT, bacterial vs.
  fungal composts and tea, human pathogen tests
• Good testimonials but variable results
• May be due to variability in the compost tea
• Know your compost tea feedstocks!
• Variability may be due to previous use of
  pesticides and fertilizers
• Not a panacea but a great tool!

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Future research

• We are all experimenters!
• If possible send sample in for testing BBC labs
  (www.bbclabs.com), Soil Food Web Inc.
• Need to understand connection between quantity,
  specific organisms, food web for disease
  suppression
• How to support the suppressive organisms and
  mechanisms that suppress disease
• Effect of cropping system-- organic vs.
  conventional
• Duff Wilson, Fateful Harvest

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Resources

• Diver, S. 1998, 2001. www.attra.org
• Ingham, E. 2001. Compost Tea Brewing Manual.
  Available through www.soilfoodweb.com
• Soil and Water Conservation Society and NRCS.
  2001. Soil Biology Primer. www.swcs.org
• Scheurell and Mahaffee. 2002. Literature Review
  Compost tea Principles and Prospects for Disease
  Control. Compost Science and Utilization
  10(4)313-338

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PNW research experiences

• Granatstein, D. 1999. Foliar disease control
  using compost teas. Compost Connection for
  Western Agriculture 81-4
• Pscheidt and Wittig. 1996. Fruit and ornamental
  disease management testing program. Ext. Plant
  Path. OSU
• Scheuerell, S. 2003.Understanding How Compost Tea
  Can Control Disease. Biocycle 44 20-25

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Photo credits not listed above

• Bacteria Credit Michael T. Holmes, Oregon State
  University, Corvallis. From Soil Biology Primer
• Fungus Credit R. Campbell. In R. Campbell. 1985.
  Plant Microbiology. Edward Arnold London. P149.
  From Soil Biology Primer

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From Growing Solutions website