Molecular Characterization of Phomopsis Vexans Inciting Fruit Rot of Brinjal (Solanum Melongena L.) Its Integrated Management and Residue Analysis of Some Fungicides

Abstract

Brinjal (Solanum melongena L.) is one of the popular vegetable crop grown in almost worldwide The Phomopsis leaf blight and fruit rot caused by Phomopsis vexans (Sacc. & Syd.) Harter is a very destructive disease of brinjal and considered to be the major constraint for limited production. Therefore, the present investigation was carried out to development an IDM module against fruit rot of brinjal. For this purpose, different fungicides, botanical extract and bio-agents were tested against Phomopsis vexans in vitro. The results revealed that, in case of fungicides, maximum 100% mycelial growth inhibition of Phomopsis vexans was recorded in Propiconazole 25 % EC, Carbendazim 12 % + Mancozeb 63 % WP, Difenoconazole 25 % EC, Azoxystrobin 18.20 % + Difenoconazole 11.40 % SC, Tebuconazole 25.9 % EC, Carbendazim 50 % WP at 100 and 150 ppm concentration. In case of botanical extract, the highest per cent mycelial growth inhibition was found in carom seed extract (48.88 %) followed by (40.14) in Bougnvillia leaf extract. In case of Bio-agents, the highest per cent mycelial inhibition was observed in Pseudomonas fluorescens (54.58 %) against Phomopsis vexans. The trial was conducted subsequently in year 2021-22 and 2022-23 for development of integrated disease management module in brinjal under field condition. The minimum PDI (7.35%) was recorded in module M6 followed by (9.75%) in module M1 and Per cent disease control was exhibited maximum in module M6 (76.64%) followed by (69.01%) in M1. the highest number of fruits per plant was recorded in module M6 (8.00) followed by M9 (7.00). amongst the modules, the maximum weight of mature fruit was recorded in module M1 (135.57gm) followed by M5 (135.20gm) and highest yield was recorded in module M6 (230.00 q/ha) followed by M1 (225.50 q/ha). The investigations concerning the residues of fungicides in brinjal fruits will help in generating information regarding the level of residue present in fruits. The residue levels of carbendazim, propiconazole and hexaconazole were found 3.36 ppm, 2.48 ppm, 1.26 at 1, days after the application and carbendazim residue at 15 day was found 0.52ppm while propiconazole and hexaconazole reached to LOQ. Amplified products of ITS primers were approximately ~ 600 bp in size estimated with the help of molecular ladder (100bp) by gel electrophoresis of all the isolates. Further, amplified product of seven isolates were eluted, purified using gel extraction kit and sent to sequencing lab (Biokart Pvt. Ltd). The ITS region sequence of Phomopsis vexans were submitted at NCBI database. All sequences resembled between 62.4-99 % nucleotides similarity within Phomopsis vexans isolates