Instituto Tecnológico de Costa Rica

BIOCONTROL EFFECT OF PSEUDOMONAS FLUORESCENS ON TWO SPECIES OF
PHYTOPATHOGENIC FUNGI FUSARIUM SP.
ABSTRACT
3
Laura Ulloa Acuña*
The application of microorganisms to control diseases in crops is a viable alternative both for
those developing countries as those where there is excessive use of pesticides that pollute the
environment, damage the soil and human health. The objective of this research was to test the
antagonistic effect making the bacteria P. fluorescens on two species of phytopathogenic fungi
for F. oxysporum and F. moniliforme to determine if the bacteria exert antagonism on these two
fungal species to be used as a biological control agent within an integrated and thus reduce the
use of fungicides on crops. Soil samples were collected within three root and potato plantations
and bacterial isolates were made and confirmatory tests (API 20E and Vitek) to show whether it
was in the presence of P. fluorescens. Was isolated three strains which were tested for
antagonism resulting, after eight days of incubation, showed a suppressive effect on the growth
of fungi in question. However, in comparison with previous studies these percentages were low.
We also assessed the compatibility of the bacterial strains against three fungicides to control
Fusarium sp, none of the three was inhibited by the chemicals.
Keywords: antagonist, P. fluorescens, F. oxysporum, F. moniliforme, biological control,
integrated management strains.
* Final Graduation Report, School of Biology, Biotechnology Engineering, Technological
Institute of Costa Rica, Cartago. 2011.