Potential of endophytic bacteria for control black pod disease of cocoa

Abstract

Black pod disease of cocoa caused by Phytophthora palmivora is a serious problem to cocoa growers in Malaysia. It is also known to cause stem canker disease where their control in infected cocoa plantations is very difficult. A study is initiated to investigate the ability of endophytes isolated from cocoa plant and their ability of these isolates to reduce black pod rot severity and to induce host plant resistance. Eighty endophytic bacteria were isolated from symptomless cocoa leaves, fruits and branches but only fourteen isolates showed inhibitory effect suppressing the mycelial growth of P.palmivora. The isolated bacteria were screened in vitro by dual culture assay and culture filtrate test for their antagonistic properties towards P.palmivora. Eight bacterial endophytes (AL4, CF1, AL3, CS1, AF1, AS1, All & CF2) showed potential as biocontrol agents based on their percentage inhibition of radial growth (PIRG) more than 50%.