Trichoderma harzianum
650 (Th650) and
Paenebacillus lentimorbus
629 (Pl629) selected earlier for their ability to control
Rhizoctonia solani
,
Fusarium solani
and
F. oxysporum in vitro, were applied alone or combined with solarization (summer assay) and/or with methyl bromide
(MeBr) (summer and winter assays) to a soil with a high inoculum level, for the control of tomato root rot caused by the complex
F. oxysporum f. sp.
lycopersici -
Pyrenochaeta lycopersici
-
Rhizoctonia solani
. Evaluations were also performed independently
for root damage caused by
P. lycopersici, and also for
R. solani in the summer assay. MeBr decreased tomato root damage caused by the
complex from 88.7% to 21.2% and from 78.4% to 35.7% in the summer and in the winter assay, respectively. None of the bio-controllers
could replace MeBr in the winter assay, but Th650 and Pl629 reduced root damage caused by this complex in the summer assay. Treatments
with bio-controllers were improved by their combination with solarization in this season. Independent evaluations showed that the positive
control of Th650 towards
R. solani and the lack of effect on
P. lycopersici correlates well with the endochitinase pattern expressed
by Th650 in response to these phytopathogens. Root damage caused by
R. solani can be controlled at a similar level as it does MeBr in summer
assays, thus representing an alternative to the use of this chemical fungicide for the control of this phytopathogen.
