Attività antimicrobica in vitro di tiofanate metile, flutolanil e ceppi di Streptomyces spp. verso funghi patogeni terricoli

IN VITRO ANTIMICROBIC ACTIVITY OF METHYL THIOPHANATE, FLUTOLANIL AND STREPTOMYCES SPP. STRAINS AGAINST SOIL-BORNE PLANT PATHOGENS The in vitro antagonistic activity of methyl thiophanate, flutolanil, Streptomyces lydicus strain WYEC 108 and Streptomyces sp. strain AtB-42 was studied using eight soil-borne plant pathogens. Methyl thiophanate was effective in reducing mycelial growth of C. destructans (LC50=0.05 g/L, LC95=9.5 g/L), F. solani (LC50=0.006 g/L, LC95=10.0 g/L), P. lycopersici (LC50=0.01 g/L, LC95=0.1 g/L), S. sclerotiorum (LC50=0.005 g/L, LC95=0.01 g/L) and V. dahliae (LC50=0.006 g/L, LC95=5.8 g/L). Flutolanil had the best performance against R. solani (LC50 0.0006 g/Land LC95 0.007 g/L). Both fungicides were not superior to propamocarb+fosetil Al, used as reference fungicide in these experiments, in inhibiting Phytium sp. and Phythophtora sp. growth. Streptomyces strains showed wide antimicrobic range. S. lydicus WYEC 108 inhibited completely the growth of all fungal pathogens tested. Streptomyces sp. AtB-42 and S. griseoviridis K61, the latter used here as reference product, reduced significantly (at least 65% and 92%, respectively), but just in a few cases completely, the growth of fungal pathogens.