Growth enhancement and management of Phytophthora - Rot in Vanilla Nurseries using microbial inoculants

Abstract

A study on “Growth enhancement and management of Phytophthora rot in vanilla nurseries using microbial inoculants” was carried out in the Department of Plant Pathology, College of Horticulture, Vellanikkara. The salient findings are abstracted below: The study revealed that Phytophthora meadii Mc. Rac.was the pathogen causing Phytophthora rot in vanilla nurseries. Even though, the treatments did not influence growth characters significantly, AMF (Perumbavoor) and Azospirillum (Mazhuvannur) were the most effective AMF and Azospirillum isolates for enhancement of growth and nutrient content in vanilla. In vitro screening of antagonists against P. meadii revealed that Trichoderma (Vellanikkara) and rhizobacteria ( Mazhuvannur) were very effective against the pathogen. The effective microbial isolates obtained were identified. Among the fungicides tested, Bordeaux mixture, copper hydroxide and copper oxychloride (at all concentrations) and potassium phosphonate (at higher concentrations) completely inhibited the growth of the pathogen. Compatibility studies revealed that potassium phosphonate was compatible with antagonists, while copper fungicides were not compatible with antagonists. Results on compatibility between Trichoderma and antagonistic bacteria showed that Trichoderma was compatible with antagonistic rhizobacteria as well as Azospirillum. The experiment on growth enhancement and Phytophthora rot management in vanilla revealed that all the microbial isolates gave early sprouting. Azospirillum (MVR) gave maximum length. AMF (PBR) and P. fluorescens (commercial) were found to be effective against Phytophthora rot in artificially inoculated vanilla cuttings. Among chemicals tested, potassium phosphonate gave best control against Phytophthora rot.