Compost tea: a brewable food web for

disease control Martha Rosemeyer

June 25, 2003

rosemeym@evergreen.edu

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