Macrophomina phaseolina (Tassi) Golidanich is a soil-borne fungus that is economically important due to the large number of plant species it infects and to its difficult control. Several studies involving inoculum density, taxonomy and survival require selective or semi-selective culture media. The aim of this study was to evaluate 16 culture media for their specificity to this pathogen, providing greater growth detection percentage and less contamination, in order to substitute the modified semi-selective medium RB, routinely used in studies with this pathogen. The modified semi-selective culture medium RB is highly efficient and contains in its composition the fungicide metalaxyl (oomycete inhibitor), which is not currently available for commercialization in its simple formularization, without the addition of Mancozeb or Chlorothalonil, which inhibit the growth of M. phaseolina. The evaluated culture media were transferred with the fungal inoculum produced in sandy organic substrate, contained in nylon bags, and recovered after 30 days from non-sterilized soil on a tray. Each evaluated culture medium had 7 replicates, represented by one Petri dish. For comparison of means of M. phaseolina growth percentages and number of contaminants, Scott-Knott test at 5% probability was used and percentage values were transformed into arc sen (√ / 100). Among the evaluated culture media, MSTP 1 [(PDA with tetracycline 50 mg.L-1 plus propamocarb 1 mL.L-1 (Previcur N® 72.2% pa)], MSRP 0.5 (PDA with rifampicin 100 mg.L-1 plus the fungicide propamocarb 0.5 mL.L-1) and MSRP 0.1 (PDA with rifampicin 100 mg.L-1 plus propamocarb 1 mL.L-1) resulted in greater percentage of detection of the fungus M. phaseolina and less contamination by other fungi and bacteria. These semi-selective culture media can be used in future research for epidemiological studies and control measures against the fungus M. phaseolina.
culture medium RB; rifampicin; tetracycline; propamocarb; fosetyl
