Biological control of maize seed pathogenic fungi by use of actinomycetes

The effectiveness of twoStreptomyces spp. strains to controlpathogenic fungi was studied in stored maizegrain. The treatments included seeddisinfection and inoculation withStreptomyces spp. strains previously isolatedfrom maize rhizosphere. Actinomycete inoculumconsisted of filtered suspension and totalsuspension of fermentor-producedStreptomyces spp. strains biomass. Treatmentswith Streptomyces spp. strains aloneeffectively suppressed the development ofAspergillus spp., Curvularia lunata, andDrechslera maydis and significantly(p < 0,05) reduced the incidence ofFusarium subglutinans and Cephalosporiumacremonium. Among the inoculation treatments,nondisinfested seed inoculated with filteredsuspension was the only treatment that did notsuppress the development of Penicilliumspp. Maize seed inoculation with totalsuspension of strains was the most effectivetreatment to control the incidence of seedpathogenic fungi. The development of theDiplodia maydis was only suppressed by thecombination of seed disinfection andinoculation with total suspension of strains.Although, the strain DAUFPE 11470 showed thegreatest effectiveness for controlling thefungi pathogenic to seed, root and shootdevelopment was reduced by treatment with thisstrain.The results indicate thatStreptomyces spp. strains reduce the incidenceof seed pathogenic fungi and have potential asa biological control agent. However, an efficient methodof seed treatment with the biological controlagent must be developed before it can become anagricultural practice.