compost tea: a brewable food web for disease control
DESCRIPTION
Compost tea: a brewable food web for disease control. Martha Rosemeyer June 25, 2003 [email protected]. Outline. Background- what is compost tea? Organisms involved Does it work? How does it work? Future research Resources How to make it- David Bell. Photo: Seth Book. - PowerPoint PPT PresentationTRANSCRIPT
Compost tea: a brewable food web for
disease control Martha Rosemeyer
June 25, 2003
Outline
Background- what is compost tea? Organisms involved Does it work? How does it work? Future research Resources
How to make it- David BellPhoto: Seth Book
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 Nutrients may be added to further increase
organisms Used for disease control, as well as a plant
nutrient source
Not to be confused with:
Manure tea made as a nutrient source
Photos: Eliot Coleman’s European tour (Diver 2001)
Plant extracts or herbal teas for disease control or plant health, for example biodynamic preparations
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
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
Organic sales increasing at 20+% per year
Worldwatch Institute. 2000. Why Poison Ourselves.
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
Ingham 2001
Without tea With Tea
Background
Since 1920’s 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
– aerated compost tea• fermented, aerated
• higher costs, energy
• little research, some disease control reports
Diver 2001
Benefits of compost tea
Nutrient application, lesser Disease control
– Foliar disease– Root disease
Inoculation of functioning soil food web
How to make non-aerobic compost tea
Mix ratio of compost to water-1:4-1:10 compost to water in an open container, stir occasionally
At least 3 days at 15-25°C (50-70 °F)
How to make Aerobic Compost Tea
Choose compost- well aged– plant based or worm compost
In water (remove chlorine from water) Ratio 1 compost:10 water to 1:50 Add nutrients (optional) like molasses, humic
acids, kelp Aerate and mix solution for 12 - 24 - 48 hours
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: compara.nl/compost_tea_systems.
Soil Soup www.soilsoup.com
Microb Brewerwww. microbbrewer.com
Growing Solutions www.growingsolutions.com
bubbling
aeration
What happens in the compost tea while brewing?
? ?
TESC Student expts: Scott Chichester and Seth Book
•Changes in compost tea during brewing •Preventing damping off of marjoram
Photos: Seth Book
Nitrate
3.23.253.3
3.353.4
3.453.5
3.553.6
0 10000 20000 30000 40000 50000 60000 70000
Time(seconds)
NO
3
ppm
Dissolved Oxygen
0123456789
10
0 20000 40000 60000 80000 100000 120000 140000 160000 180000
time(seconds)
DO
(pp
m)
ppm
24 hrs
20 hrs
48 hrs
Dissolved Oxygen >5.5 ppm
From: Book and Chichester
pH > 7.2pH
7.15
7.2
7.25
7.3
7.35
7.4
0 10000 20000 30000 40000 50000 60000 70000
Time(seconds)
pH
Temperature(compost tea solution)
25.325.425.525.625.725.825.9
26
0 10000 20000 30000 40000 50000 60000 70000
Time(seconds)
Tem
per
atu
re(C
)
°C
From: Book and Chichester
Food web concept
”Everything eats, everything excretes, and everything is food for something" – Elaine Ingham, 2001
A great resource:
SWCS/NRCS,
Soil Biology Primer
A functioning food web is desirable in a compost tea
From: Soil Biology Primer
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 maybe active in each acre of soil. Bacteria dot the surface of strands of fungal hyphae.
From: Soil Biology Primer
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
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
bacteria
From: Soil Biology Primer
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
Interaction
Vampyrellidae attack fungus “take all” of wheat
cysts
From: Soil Biology Primer
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
Interactions: Nematode trapping fungi
From: Soil Biology Primer
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!
Do we know what the diversity or quantity of microbes means with respect to disease?
Not entirely Most soil organisms are unknown! Does microbial diversity increase microbial
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
Does it work? NCT- Good evidence under
certain circumstances Much research with
– grey mold
(Botrytis cineraria)
Downy mildew of grape
(Plasmopara viticola)
Late blight of potato, tomatoPhytopthora infestans
Horse compost extractWeltzein (1990)
Gray mold on beans, strawberriesBotrytis cinerea
Cattle compost extractWeltzein (1990)
Fusarium wiltFusarium oxysporum
Bark-compost extractKai, et al (1990)
Downy & Powdery mildew-grapesPlasmopara viticolaUncinula necator
Animal manure-straw compostextractWeltzein (1989)
Powdery mildew on cucumbersSphaerotheca fuliginea
Animal manure-straw compostextractWeltzein (1989)
Gray mold on tomato, pepper Cattle & chicken manure compostextractGrape marc compost extractElad, Shtienberg (1994)
Apple scabVenturia conidia
Spent mushroom compost extractCronin, Andrews (1996)
Diver, 1998
Evidence of NCT disease suppression
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
Apple scab control using NCT but not 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
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
Tests for Disease control of ACTControl of:Brown rot blossomblight of sweetcherry (Monilinialaxa)
No control:PM of apple,grape, apple andpear scab, brownrot of peach,peach leaf curl,cherry leaf spot
Reference:Pscheidt andWittig 1996
Lettuce drop, postharvest fruit ofblueberry
Early blight oftomato
Granatstein 1999
Powdery mildew ofrose (Sphaerothecapannosa var. rosae)
Scheuerell andMahaffee 2000
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
Disease control with ACTPresidio golf greens
Decreased No effect
Microdochium Anthracnose
Conforti et al. 2002
Bacterial vs. fungal dominated teas can be determined by added
nutrients (Ingham 2001) Bacterial- use simple sugars to fulvic acids Fungal- use humic acids
Have been difficult for some to produce fungal dominated teas (Scheuerell and Mahaffee 2002)
Reports on reduction of suppression due to nutrient competition?
Useful to know nutrients that support antagonists
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
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
Predation NCT: Fusarium spore rupture
Root drench for Fusarium diseases of pepper and cucumber
Direct destruction on disease-causing spores
Ascospores of Fusarium solani
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)
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)
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]
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 amoeba-type protozoa 20-50 ciliates protozoa 2-10 beneficial nematodes (soil drench)
How to test?
Send compost tea to Soil Food Web (direct counts)
BBC Labs, Vicki Bess
Need to correlate counts to field performance
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 (Escherichia, Salmonella, Shigella, Yersinia) even if contain low levels of pathogens
If use worm compost as source appears that can avoid pathogens
Needs more research
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 due to compost quality, fermentation nutrients, fermentation time and specific microbial antagonists
Variability may also be due to previous use of pesticides and fertilizers
Important to understand how compost tea production and application interact with the pathogen’s biology, put your plan into practice and carefully observe results
Not a panacea but a great tool!
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, add biocontrol agents
Effect of cropping system-- organic vs. conventional --Duff Wilson, Fateful Harvest
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
Brinton, W.F. et al. 1996. Investigations into liquid compost extracts. Biocycle 37:68-70
PNW research experiences
Granatstein, D. 1999. Foliar disease control using compost teas. Compost Connection for Western Agriculture 8:1-4
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
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
From: Growing Solutions website