Evaluation of Bacillus subtilis and Bacillus pumilus as Potential Biological Control Agents against Peanut Late Leafspot (Cercosporidium personatum in-vitro)

Abstract

A study was conducted to determine the inhibitory effect of Bacillus subtilis and B. pumilus against the causal pathogen of late leafspot (Cercosporidium personatum) In-vitro. Infected leaf samples were collected from peanut fields in Burgos, La Union. Isolation of the pathogen from the infected leaves was done at the Plant Pathology Laboratory, College of Agriculture, Benguet State University, La Trinidad, Benguet. The pathogen and the biocontrol agents were prepared in ready for the bioassay. Inhibition zones produced by the Bacillus subtilis and B. pumilus against Cercosporidium personatum were measured. Results showed that B. subtilis isolates (PCN 2011 – 005, PCN 2011 – 002, St 2011 – 001) and B. pumilus (131) inhibited the growth of C. personatum but not significantly different with the negative control. Nevertheless, the presence of the inhibition zone, regardless of size, is an adequate indication of their potential ability to control the pathogen. It is recommended that another study shall be conducted identifying and using the metabolites of the same biological control agents instead of the live specimens used. Further studies shall be done using potted plants then to the actual field condition.