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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