Phylloplane microflora diversity of cucumber and their antagonistic activity against powdery mildew

Abstract

The diversity of phylloplane microflora of cucumber was studied during the 2021-2022 growing season. Eight microorganisms comprising Fusarium sp., Penicillium sp., Aspergillus sp., Alternaria sp., Trichoderma sp., and three isolates of bacterial were recovered from the leaf surface of cucumber. Among these, Fusarium, Aspergillus, Penicillium, and the bacterial isolates exhibited the highest frequency of occurrence, whereas Trichoderma sp. appeared at a lower frequency. The antagonistic potential of the isolated microflora against the powdery mildew pathogen was evaluated under in vitro conditions using the slide spore germination technique. All culture filtrates significantly reduced conidial germination of the pathogen. The maximum inhibition of conidial germination (22.50%) was observed with Trichoderma sp., followed by Alternaria sp., Fusarium sp., and the bacterial isolates. The least inhibitory in recorded with Aspergillus sp. and Penicillium sp.