ISOLATION AND CHARACTERIZATION OF A PSEUDOMONAS-FLUORESCENS STRAIN SUPPRESSIVE TO BIPOLARIS-MAYDIS

Strain PJ0210, identified as Pseudomonas fluorescens, inhibited Bipola ris maydis both in vitro and in vivo. The absence of detectable inhibi tory substances assayed by a variety of methods indicated nutrient com petition as the operative component of antagonism. This was further su pported by observations of reduced inhibition by addition of glucose b oth in vitro and in vivo. Strain PJ0210 was adapted to the phyllospher e showing good survivability and colonizing ability both in plant hous e and field trials. Disease suppression was generally correlated with population sizes of strain PJ0210. Population sizes in the field were lower than those recorded in the plant house with a concomitant reduct ion in disease suppressive ability of strain PJ0210.