Vol. 12, Issue 11 (2023)

Author(s):
Anjali P, Deepa James, Reshmy Vijayaraghavan and Mini Sankar

Abstract:
In an orchid nursery of Cattleya in Thiruvananthapuram district of Kerala, a leaf spot disease was noticed prominent. The pathogen isolated was identified as Lasiodiplodia theobromae based on cultural, morphological and molecular characterisation. To the best of our knowledge, this is the first report of L. theobromae causing leaf spot disease in Cattleya from India. The efficacy of eight fungicides was evaluated against L. theobromae, of which the fungicides viz., cymoxanil 8% + mancozeb 64%, carbendazim 12% + mancozeb 63%, propineb and 1% Bordeaux mixture completely inhibited the mycelial growth, while azoxystrobin was found to be least effective against the pathogen. Among the biocontrol agents tested, plant growth promoting microorganisms (PGPM) showed 100% inhibition, followed by plant growth promoting rhizobacteria-II (PGPM-II) (50.41%) and Trichoderma asperellum (20.41%), while Pseudomonas fluorescens did not show any inhibition.