Potential biocontrol of Sclerotinia homoeocarpa and Bipolaris sorokiniana on the phylloplane of Poa pratensis with strains of Pseudomonas spp.

Four Pseudomonas strains were evaluated for their ability to control Sclerotinia homoeocarpa and Bipolaris sorokiniana on the phylloplane of Poa pratensis (Kentucky bluegrass). The strains evaluated were Pseudomonas fluorescens (PSD‐4, PSD‐5, PSD‐6) and Pseudomonas lindbergii (PSD‐42). All evaluations were conducted on the upper epidermis of intact attached leaves of Poa pratensis and antagonism was measured as the ability of strains of Pseudomonas to prevent chlorophyll loss from leaves inoculated with either S. homoeocarpa or B. sorokiniana. All strains prevented infection and loss of chlorophyll following inoculation with S. homoeocarpa. Only P. lindbergii (PSD‐42) was antagonistic to B. sorokiniana. None of the P. fluorescens strains controlled disease induced by B. sorokiniana.