Eco-friendly strategies for the management of Curvularia spicifera through phytobiocides and biological antagonists

Over the past few decades, several biotic stresses caused severe economic losses in Peach orchards in Northwest Pakistan. To investigate some of the causal agents, we isolated fungi from fruits with brown to black colored small sunken lesions in several orchards of the Swat valley in northwest Pakistan. Morphological characterization coupled with ITS-based barcoding revealed C. spicifera to be associated with the peach fruit rot. The pathogenicity of C. spicifera was confirmed through Koch’s postulates. Among four growth media, C. spicifera showed rapid growth on acidified potato dextrose agar (APDA). Eco-friendly strategies for developing control measures of C. spicifera were also evaluated. In vitro analysis revealed that the mycelial growth of C. spicifera was inhibited by crude extracts from Casuarina equisetifolia, Capsicum annuum, Parthenium hysterophorus, Withania coagulans and Cannabis sativa. The extracts showed different degrees of inhibition; the most effective were methanol, ethyl acetate, chloroform and butanol extracts from C. annuum; ethanol extract of Withania coagulans and n- hexan extract of P. hysterophorus. Furthermore, we evaluated the antifungal activity of different concentration of essential oils (EO) using the disc diffusion method. EO obtained from Euclaptus citriodora, Mintha piperita, Cymbopogan citratum and Ocimum tenuiflorum effectively inhibited mycelial growth of C. spicifera at a concentration of 40-60ul/ml after seven days of incubation. Finally, we tested the antagonistic effect of Bacillus subtilis and Trichoderma harzianum against C. spicifera at 12 days after incubation. B. subtilis and T. harzianum inhibited growth of C. spicifera up to 95% and 80%, respectively. These findings provide information on devising alternatives to synthetic fungicide in the field to manage the newly identified C. spicifera from Peach fruits.