BIOCONTROLE OF MACROPHOMINA PHASEOLINA AND PROMOTING GROWTH IN SUNFLOWER CULTURE WITH THE USE OF TRICHODERMA SP. AND RHYDROBACTERIA

Abstract

PHYTOPATHOGENIC FUNGI INHABITING THE SOIL SUCH AS MACROPHOMINA PHASEOLINA ARE DIFFICULT TO CONTROL, MAINLY BECAUSE THEY FORM RESISTANCE STRUCTURES. AS IT IS A POLYPHAGOUS SPECIES, IT IS NECESSARY TO CARRY OUT STUDIES TO OBTAIN DIFFERENT EFFECTIVE FORMS OF CONTROL. THEREFORE, THE OBJECTIVE OF THIS WORK WAS TO TEST THE EFFICIENCY OF BENEFICIAL MICROORGANISMS IN THE BIOLOGICAL CONTROL OF M. PHASEOLINA, AND IN THE PROMOTION OF GROWTH TO THE SUNFLOWER CULTURE. THE PRESENT RESEARCH WAS CARRIED OUT IN TWO STAGES, ONE WITH AN IN VITRO TEST AND ANOTHER WITH AN IN VIVO TEST. THE IN VITRO TEST WAS CONDUCTED IN THE MICROBIOLOGICAL ANALYSIS LABORATORY AGROLAB, WHERE A CULTURE PAIRING TEST WAS PERFORMED WITH SIX TREATMENTS AND THREE REPLICATIONS, (T1 - TRICHODERMA SP. + PATHOGEN; T2 - BACILLUS SP. + PATHOGEN; T3 - B. PYRROCINIA + PATHOGEN; T4 - P. FLUORESCENS + PATHOGEN; T5 - B. SUBTILIS + PATHOGEN AND T6 - PATHOGEN ONLY), THE OCCURRENCE OF ANTIBIOSIS WAS EVALUATED AND THE MOST PROMISING ISOLATES WERE SELECTED FOR THE IN VIVO ASSAY. THE IN VIVO TEST WAS CARRIED OUT IN THE EXPERIMENTAL UNIT OF THE AGROLAB LABORATORY, IN 400 ML CONTAINERS, IN PROTECTED CULTIVATION, BEING CONDUCTED IN A COMPLETELY RANDOMIZED DESIGN WITH FIVE TREATMENTS (T1 - CONTROL; T2 - TRICHODERMIL^�®; T3 - TRICHODERMA SP.; T4 - B. PYRROCINIA AND T5 - B. SUBTILIS) IN EIGHT REPETITIONS. THE CAPACITY OF BIOAGENTS TO SUPPRESS THE SEVERITY OF THE DISEASE AND THEIR EFFICIENCY AS GROWTH PROMOTERS FOR SUNFLOWER CULTIVATION WERE EVALUATED. THE PARAMETERS EVALUATED IN THE GROWTH ANALYSIS WERE: ROOT LENGTH AND AERIAL PART AND, BIOMASS OF THE ROOT AND AERIAL PART. THE RESULTS SHOWED A SIGNIFICANT DIFFERENCE BETWEEN THEM BY THE F TEST (P <0.05). IN IN VITRO TESTS, THE ISOLATES OF TRICHODERMA SP., BACILLUS SUBTILIS AND B. PYRROCINIA REPORTED BETTER ANTAGONISTIC ACTIVITY WITH 10.93%, 10.26% AND 3.71% INHIBITION OF THE MYCELIAL GROWTH OF THE PATHOGEN, RESPECTIVELY. IN PROMOTING GROWTH, ALL TREATMENTS PROMOTED GREATER ROOT LENGTH AND INCREASED SHOOT BIOMASS. THERE WAS NO SIGNIFICANT DIFFERENCE IN THE LENGTH OF THE AERIAL PART IN RELATION TO THE CONTROL, AND THE ISOLATES OF B. SUBTILIS, B. PYRROCINIA AND TRICHODERMA SP. SHOWED HIGHER ROOT BIOMASS. IN THE SEVERITY OF THE DISEASE, TREATMENTS WITH B. SUBTILIS, B. PYRROCINIA, TRICHODERMA SP. AND TRICHODERMIL^�®, PRESENTED 90.5%, 81.0%, 81.0% AND 62.5% OF PATHOGEN SUPPRESSION, RESPECTIVELY. IT WAS CONCLUDED THAT THESE MICROORGANISMS HAVE POTENTIAL AS GROWTH PROMOTERS AND BIOCONTROLLERS OF THE DISEASE, AND CAN BECOME A VIABLE TECHNIQUE TO BE INCLUDED IN INTEGRATED DISEASE MANAGEMENT.