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Custom
Biologicals, Inc.
TECHNICAL
DISCUSSION #7
Basal Stem
Rot (BSR) in Palm
Basal Stem Rot
(BSR) disease caused by Ganoderma
boninense is the most destructive
disease in oil palm and is of major economic
importance, especially in Indonesia and
Malaysia.
The available control measures for
BSR disease such as cultural practices and
mechanical and chemical treatment have not
proved satisfactory due to the fact that
Ganoderma has various resting stages such as
melanised mycelium, basidiospores and
pseudosclerotia.
The pathogen is spread via airborne
basidiospores, root contact with infested
soil, and root graft transmission. It can
spread horizontally in the soil up to around
2m from diseased to healthy host roots.
Basidiospores infect wound sites on trunks
or the cut ends of palm fronds.
Astute observations of the low
incidence of disease due to pathogenic
Ganoderma species in some natural stands,
suggest that the disease is most likely kept
under control by some biological means. Due
to these observations, recent control
measures to overcome the Ganoderma
problem are now focused on the use of
biological control agents. There are an
abundance of studies showing that
Trichoderma species inhibit the growth of
Ganoderma species and is the most promising
of all biocontrol agents for Ganoderma.
This inhibition
has been confirmed by excellent studies by
such esteemed research institutes as: the
Indonesian Oil Palm Research Institute; the
Department of Plant Protection, Universiti
Putra, Malaysia; the Department of
Biology, University of Putra, Malaysia; the
Center for Plant Protection Studies, Tamil;
and the Nadu Agricultural University, Tamil,
Nadu, India.
These studies have mainly been in glass
houses, with some field observations and
some field trials. Almost all of these
studies have shown that Trichoderma spp.
which are saprophytic fungi with high
antagonistic activities against soil-borne
pathogens, is the most likely candidate for
a biocontrol product for Ganoderma.
Application
The situation that would show the most
benefit with biocontrol measures would be
with soil augmentation at the time of
planting of the new palm trees where
Trichoderma could be incorporated in the
root system and in the soil around the new
tree. It would also be valuable for
protecting the root system of mature trees
by surface application to the soil up to six
feet around the base.
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