USE OF BIOAGENTS IN THE SUPPRESSION OF MACROPHOMINA PHASEOLINA IN THE COMMON BEAN CULTURE

Abstract

MACROPHOMINA PHASEOLINA CAUSES GRAY-STEM-ROT DISEASE IN COMMON BEAN CULTURE AND LEADS TO SIGNIFICANT GRAIN LOSSES DUE TO DIFFICULTIES IN CONTROL. THEREFORE, THE OBJECTIVE OF THIS WORK WAS TO EVALUATE THE EFFECT OF USING TRICHODERMA AND RHIZOBACTERIA AS BIOAGENTS IN THE SUPPRESSION OF THE DISEASE IN THE COMMON BEAN CULTURE. THE EXPERIMENT WAS CARRIED OUT IN A SCREENED CONDITION AND A COMPLETELY RANDOMIZED BLOCK DESIGN WAS ADOPTED. SIX TREATMENTS WERE CARRIED OUT WITH EIGHT REPETITIONS. THE TREATMENTS CONSISTED OF: T1 - CONTROL; T2 - PSEUDOMONAS FLUORESCENS; T3 - BURKHOLDERIA PYRROCINIA; T4 - BACILLUS SP.; T5 - TRICHODERMIL 1306^�® AND T6 - RANCONA T^�®. THE TREATMENTS WERE APPLIED VIA SEED AND LEAF SPRAY AT 14 AND 21 DAYS AFTER PLANTING. THE PHYTOPATHOGEN MACROPHOMINA PHASEOLINA WAS INOCULATED AT 21 DAYS AFTER PLANTING, USING THE TOOTHPICK METHOD. THE EVALUATION OF THE SEVERITY OF THE DISEASE AND THE AREA UNDER THE DISEASE PROGRESS CURVE WAS PERFORMED AT 1, 2, 4 AND 8 DAYS AFTER INOCULATION, USING A SCALE OF DESCRIPTIVE NOTES. THE EVALUATION OF GROWTH PROMOTION WAS CARRIED OUT AT 21 DAYS AFTER PLANTING. BEAN PLANTS THAT HAD SEED TREATMENT AND LEAF SPRAYING WITH RHIZOBACTERIA P. FLUORESCENS AND BACILLUS SP. STOOD OUT SIGNIFICANTLY, INCREASING SHOOT BIOMASS BY 46.73% AND 41.43%, RESPECTIVELY, COMPARED TO THE CONTROL. PLANTS TREATED VIA SEEDS AND FOLIAR SPRAY WITH THE RHIZOBACTERIUM BACILLUS SP. PRESENTED A LOWER SEVERITY INDEX OF THE DISEASE, WITH A SUPPRESSION OF 51.67% IN RELATION TO THE CONTROL. ACCORDING TO AREA UNDER THE DISEASE PROGRESS CURVE, THE TREATMENT THAT PRESENTED THE SMALLEST AREA WITH THE PRESENCE OF SICK PLANTS WAS THE TREATMENT WITH THE BACTERIUM BACILLUS SP. WITH 34.58%. ACCORDING TO THE RESULTS OBTAINED, THE USE OF BACILLUS SP. AND TRICHODERMA HARZIANUM WERE EFFICIENT IN SUPPRESSING MACROPHOMINA PHASEOLINA IN COMMON BEAN CULTURE. THE USE OF PSEUDOMONAS FLUORESCENS AND BACILLUS SP. ARE EFFICIENT IN PROMOTING AERIAL BIOMASS GROWTH.