Efficacy of Selected Bacterial Antagonists (Burkholderia sp.) in Managing Colletotrichum truncation Infection off Chilli Fruits

Abstract

Anthracnose disease causes high yield losses in chilli mainly due to postharvest fruit decay. The disease affects fruit yield and quality; therefore, control measures have to be applied at the correct time. In a new paradigm shift from synthetic fungicides to a safer and environmentally friendly alternative for managing post-harvest decays in fruits and vegetables, efficacy of some selected antagonistic Burkholderia species against anthracnose fruit decay was assessed in this study. Chilli fruits at different fruit growth stages, green (21 days after fruit setting), colour breaking (28 days after fruit setting) and red (35 days after fruit setting) stages were used for the assay in order to find out the most suitable stage to apply these antagonists to prevent anthracnose disease development. Detached chilli fruits of the three growth stages were first treated with overnight broth cultures of the antagonists and incubated for 24 hours in a humid chamber. Inoculation with pathogen was done 24 hours after incubation by using both wounding and non-wounding methods. Recovery from anthracnose was effective at both green and colour breaking stages of chilli fruits. Fruits at colour breaking stage showed a remarkable disease recovery in response to applied bacterial antagonists both in wounded (32.52% - 80.97%) and non- wounded (100% ) inoculations. Green stage chilli fruits also showed a significant disease recovery (at p<0.05 level) ranging from 19.58% -100% in non-wounded inoculation. Red chilli fruits showed a rotting tendency when treated with antagonists, implying that, this fruit growth stage is not appropriate in applying antagonists as a control measure to prevent anthracnose. Therefore, harvesting period of chilli is the most appropriate time to treat fruits with these antagonists in order to prevent postharvest anthracnose incidence. Results of this study prove the suitability of application of these antagonists at the colour breaking stage of chilli to effectively manage postharvest anthracnose fruit decay.