Field Guide of Discovery-based Exercises for - Aseanipm ...

Exercise No. 5.16 206
USING TRICHOdERMA AS BIOLOGICAL CONTROL
AGENT OF DAMPING-OFF PATHOGENS IN
ORGANICALLY-GROWN TOMATOES
BaCKGroUND aND raTIoNalE
Damping-off is the most important disease of tomato
especially in seedbeds. The three fungal pathogens that cause
damping-off in tomatoes are Sclerotium rolfsii, Rhizoctonia
solani, and Pythium sp. In case of severe damping-off
incidence, only about half of tomato seeds sown in seedbeds
would be able to germinate. When disease pressure is too
high, some vegetable farmers change seedbed areas after
several plantings to escape this disease. Most farmers sow
large volume of seeds to ensure survival of enough seedlings
for transplanting.
304
Field Guide of Discovery-based Exercises for Organic Vegetable Production
when is this exercise most
appropriate?
ɶ In FFS, TOT, and
VST sessions, prior
to or during seedbed
preparation and as
component of topic on
‘Integrated Disease
Management’; and
ɶ When farmers want to
learn innovative practices
in using Trichoderma
for biological control
of damping-off in
organically-grown
tomatoes.
Nowadays, trend in pest and disease management is towards biological control. This is due to
unintended impact of continuous chemical pesticides use (e.g., environmental pollution, health
hazards, and disruption to ecosystem functions). Among biological control agents, Trichoderma
sp., a common soil fungus is receiving a great deal of attention. Trichoderma is a natural component
of soil micro-flora. It is fast growing and secretes many hydrolytic enzymes. These traits make
this fungus a good decomposer of soil organic matter. In fact, aside from its antagonistic nature
towards several plant pathogens, Trichoderma was also observed by organic vegetable farmers in
Benguet and Mountain Province as a compost-decomposer and growth-enhancer of tomato and
celery. These observations were also reported in Taiwan.
Recently, its use as biological control agent (bio-con) against damping-off in tomatoes has become
attractive alternative to chemical pesticides. The effectiveness of Trichoderma in controlling this
disease was proven in field trials conducted with tomato farmer-cooperators in Laguna. Seedbeds
treated with Trichoderma (e.g., pseudokoningii, parceramosum and harzianum species) showed
about 90% survival compared with only 14% in untreated ones. Aside from pellet form, powder
form of Trichoderma is now commercially available in 250-gram pack. One pack of product is
enough to treat seeds good for one-hectare planting. The product can also be applied directly to
seedbed 3 days before seed sowing at 3.0 grams per square meter.
206 Sinohin, A.M. and V.C. Cuevas. 2005. Biological control of damping-of pathogens of tomato. Paper presented during a Workshop on Integrated Production
and Pest Management in Processing Tomato: Issues and Prospects held on July 2005 at Laoag City, Ilocos Norte, Philippines. 6p.