Basilios Papageorgiou, Jürgen Helbig,
Carmen Büttner:
Ability of Watery Extracts of Composted Organic Waste from
Urban Households to Control Airborne Plant Pathogens
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BASILIOS
PAPAGEORGIOU,
JÜRGEN
HELBIG,
CARMEN
BÜTTNER
Humboldt
University Berlin, Institute of Horticultural Sciences, Germany
The effect of compost applications on plant health has mainly been
investigated regarding soil borne diseases. The few investigations on the
effectiveness of shoot treatments with watery compost extracts showed that
leaf pathogens were effectively controlled and that different mechanisms
seemed to be involved. Additionally to systemically acquired induced
resistance, some other antagonistic mechanisms of the microorganisms present
in compost extracts were observed, including production of antibiotics,
concurrence for nutrients or parasitism. In the present investigation, the
effectiveness of watery extracts from composts that were produced from organic
household waste in West Africa, was examined using the pathosystem tomato and
Alternaria solani.
Applications of watery
compost extracts successfully suppressed infection of A. solani on tomato. Different factors were
checked for their impact on the effectiveness of the extracts and the density
of microorganisms present in the extracts. Temperature and frequency of
stirring significantly influenced the density of microorganisms and the
effectiveness against A. solani. Daily
stirring of the compost-water mixture during the extraction period
(3 days) increased the density of microorganisms sevenfold and disease
incidence was reduced by [27]% as compared to the treatment with only one
initial stirring. The incubation of the compost-water mixture at [20]C
increased the number of microorganisms in the extract tenfold as compared to
mixtures incubated at 30 and [35]C. The extract incubated at [20]C
reduced incidence of A. solani by [66]%
as compared to the control, whereas the other variants were less effective.
The formulation substances
cellulose, alginate and xanthan were added to the extracts to increase their
effectiveness against the pathogens. The extract enriched with xanthan reduced
disease incidence on tomato by [23]% as compared to the extract without
formulation substances.
Storage duration of the
composts after their preparation significantly influenced the density of
microorganisms present in the extracts and their effectiveness against A. solani on tomato. Those composts that were
stored for a shorter period showed a higher number of microorganisms in the
extract and a higher effectiveness of the extracts
Tom Jaszewski
www.livesoil.com
702-595-7012
-----Original
Message-----
From: Ross Orner
[mailto:rorner@pennswoods.net]
Sent: Sunday, February 09, 2003 7:28
PM
To:
compost_tea@yahoogroups.com
Subject: [compost_tea] early blight in
tomatoes
Does
anyone have any experience with the effects of compost tea on early
blight on tomatoes? This is a problem disease for a producer in New Jersey
conditions.
Thank
you,
Ross
Orner
www.
ornerfarms.com
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