Biochemical profiling of selected plant extracts and their antifungal activity in comparison with fungicides against Colletotrichum capsici L. causing anthracnose of Chilli

Chili (Capsicum annuum L.) is the utmost significant cash crop of Pakistan. Annually, about 50% chili yield is reduced by chili anthracnose disease caused by Colletotrichum capsici. The current study was conducted to explore the antifungal potential of plant extracts in comparison with commercial fungicides against C. capsici. Morphologically recognized strains of C. capsici were subjected to pathogenicity assay where strain CC-2 showed a highly virulent response. Results from in-vitro studies showed that Ginger (15 % concentration) inhibited fungal mycelial growth and spore germination and results were comparable to Nativo and Antracol at 1000 ppm. From the protective and curative trials, among plant extracts, Ginger at 15% showed maximum crop protective activity (84%) and maximum curative activity (70%). Consequently, among fungicides, Antracol at 1000 ppm showed highest crop protective activity (92%) and maximum curative efficacy (96%). The results of pot experiments showed that among the plant extracts, Ginger significantly inhibited C. capsici and increased plant growth while among fungicides, Antracol was found to be more effective than Nativo. PCA explored the correlation between growth parameters of chili plants treated with plant extracts and fungicides. Biochemical profiling and phytochemical characterization indicated the presence of tannins, phenols, terpenoids, flavonoids, alkaloids, reducing sugars and anthraquinones in ginger and chicory extracts. Ginger showed the highest DPPH scavenging activity (64.9 +/- 1.85) as compared to chicory (54.6 +/- 2.8). GC-MS analysis of plant extracts revealed the presence of various bioactive compounds including Ethanol, Acetone, 2-Butanone, Trichloromethane, 2-Butanone, 4(4-hydroxy-3-methoxyphenyl)-, Gingerol, 1, 2-Benzenedicarboxylic acid, diisooctyl ester, Hexane, Glycerin, Sucrose, Hexadecanoic acid, methyl ester, 9-Octadecenoic acid (Z)-, methyl ester, 1,2-Benzenedicarboxylic acid, mono (2-ethylhexyl) ester, n-Hexadecanoic acid, cis-Vaccenic acid, 1-Monolinoleoylglycerol trimethylsilyl ether, and 9,12,15-Octadecatrienoic acid, 2-[(trimethylsilyl)oxy]-1-[[(trimethylsilyl)oxy] methyl]ethyl ester, (Z,Z,Z). FTIR analysis showed 12, 8 and 13 peak values respectively indicating the presence of important functional groups. NMR analysis showed 4 and 7 peak values of ginger and chicory extracts indicating the structures of functional groups. There is a need to test the disease suppressive potential of plant extracts under field conditions to manage other fatal plant pathogens.