1. Compost tea: a brewable food web for disease control
Martha Rosemeyer
June 25, 2003

2. 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

3. 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

4. Not to be confused with:
Plant extracts or herbal teas for disease control or plant health, for example biodynamic preparations
Manure tea made as a nutrient source
Photos: Eliot Coleman’s European tour (Diver 2001)

5. 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

6. 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

7. Organic sales increasing at 20+% per year
Currently $22B ww
Worldwatch Institute Why Poison Ourselves.

8. 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

9. 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

10. aerated compost tea fermented, aerated higher costs, energy
little research, some disease control reports
Diver 2001

11. Benefits of compost tea
Nutrient application, lesser
Disease control
Foliar disease
Root disease
Inoculation of functioning soil food web

12. 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)

13. 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 hours

14. Commercial aerobic compost tea brewers
Soil Soup:
Microb Brewer:
Growing Solutions:
Earth Tea Brewer:
Xtractor: compara.nl/compost_tea_systems.

15. Soil Soup www.soilsoup.com

16. Microb Brewer www. microbbrewer.com

17. Growing Solutions www.growingsolutions.com
bubbling
aeration

18. What happens in the compost tea while brewing?
? ?

19. TESC Student expts: Scott Chichester and Seth Book
Changes in compost tea
during brewing
Preventing damping off
of marjoram
Photos: Seth Book

20. Dissolved Oxygen >5.5 ppm
24 hrs
48 hrs
ppm
20 hrs
From: Book and Chichester

21. From: Book and Chichester
pH > 7.2 °C
From: Book and Chichester

22. Food web concept
”Everything eats, everything excretes, and everything is food for something"
Elaine Ingham, 2001
A great resource:
SWCS/NRCS,
Soil Biology Primer

23. A functioning food web is desirable in a compost tea
From: Soil Biology Primer

24. 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

25. 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

26. Mycorrhizal fungus stained blue Non mycorrhizal
Roots of Common Bean (Phaseolus vulgaris)
from Costa Rica
Mycorrhizal fungus
stained blue
Non mycorrhizal
Photo: Rosemeyer

27. Mycorrhizal fungi link root cells to soil particles
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

28. From: Soil Biology Primer
Actinomycetes, such as this Streptomyces, give soil and compost
its "earthy" smell.
Soil Microbiology and Biochemistry Slide Set J.P. Martin,
et al., eds. SSSA, Madison, WI
From: Soil Biology Primer

29. From: Soil Biology Primer
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

30. 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

31. From: Soil Biology Primer
cysts
Interaction
Vampyrellidae attack fungus “take all” of wheat
From: Soil Biology Primer

32. 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

33. Interactions: Nematode trapping fungi
From: Soil Biology Primer

34. 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!

35. Video: Life in the Soil produced by Sakura Motion Picture Co. , Ltd
Video: Life in the Soil produced by Sakura Motion Picture Co., Ltd.[and] MOAProductions; planned by Nature Farming International Research Foundation Atami, Japan

36. Total population of active microbes
Bacteria minimum (Scheurell and Mahaffee)
But may not be associated with disease control, if appropriate agent not present!

37. 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

38. Does it work? NCT- Good evidence under certain circumstances
Much research with
grey mold
(Botrytis cineraria)
Downy mildew of grape
(Plasmopara viticola)

39. Evidence of NCT disease suppression
Diver, 1998

40. 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

41. Apple scab on leaf and fruit
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

42. Powdery mildew of rose (Scheurell and Mahaffee 2000)
Three sources of compost
ACT commercial preparation vs 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

43. 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)

44. Tests for Disease control of ACT

45. Disease control with ACT Granatstein 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

46. Disease control with ACT Presidio golf greens
Decreased No effect
Microdochium Anthracnose
Conforti et al. 2002

47. 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

48. 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

49. 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

50. Predation NCT: Fusarium spore rupture
Root drench for Fusarium diseases of pepper and cucumber
Direct destruction on disease-causing spores
Ascospores of Fusarium solani

51. 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)

52. 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)

53. 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]

54. Minimum standards for compost tea/mL (Ingham 2001)
g active bacteria, 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)

55. How to test? Send compost tea to Soil Food Web (direct counts)
BBC Labs, Vicki Bess
Need to correlate counts to field performance

56. 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

57. 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

58. 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!

59. Future research We are all experimenters!
If possible send sample in for testing: BBC labs ( 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

60. Resources Diver, S. 1998. 2001. www.attra.org
Ingham, E Compost Tea Brewing Manual. Available through:
Soil and Water Conservation Society and NRCS Soil Biology Primer.
Scheurell and Mahaffee Literature Review: Compost tea: Principles and Prospects for Disease Control. Compost Science and Utilization 10(4):
Brinton, W.F. et al Investigations into liquid compost extracts. Biocycle 37:68-70

61. PNW research experiences
Granatstein, D Foliar disease control using compost teas. Compost Connection for Western Agriculture 8:1-4
Pscheidt and Wittig Fruit and ornamental disease management testing program. Ext. Plant Path. OSU
Scheuerell, S Understanding How Compost Tea Can Control Disease. Biocycle 44: 20-25

62. 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 Plant Microbiology. Edward Arnold; London. P149. From: Soil Biology Primer

63. From: Growing Solutions website