RESUMEN
Aims: To test the effect of bacterial biocontrol agents (Pseudomonas-TNAU-Pf1) and fungicides (Tricyclazole) individually and their integration as seed treatment and foliar spray against finger millet blast under field conditions.Study Design: The field experiments were conducted in a Randomized Block design.Place and Duration of Study: The experiments were conducted at the Regional Research Station farm, Tamil Nadu Agricultural University, Paiyur, Krishnagiri District, Tamil Nadu, India, during 2016-17 and 2017-18.Methodology: Two field experiments were conducted to evaluate the efficacy of talc-based formulation of Pseudomonas -TNAU-Pf1 and Tricyclazole individually and in combination as seed treatment and foliar application for the management of finger millet blast with five treatments and four replications using a variety Paiyur 2. The bioagent and the fungicide were applied as seed treatment and foliar spray.Results: The results revealed that seed treatment with talc-based formulation of Pseudomonas -TNAU-Pf1 (10g/kg) plus two sprays of tricyclazole (0.1%) one at the maximum tillering phase and another at the heading phase was significantly most effective in reducing leaf, neck and finger blast in both the seasons. The treatment recorded 1.65 and 1.25PDI of leaf blast, 0.33 and 0.22% of neck and 2.55 and 1.33% of finger blast in the first and second season, respectively. The treatment also recorded highest grain yield of 2663 and 2543 kg/ha with BC ratio of 1:3.94 and 1:3.85 in the first and second season, respectively.Conclusion: Seed treatment with Pseudomonas TNAU-Pf1 (10g/kg) plus two sprays of tricyclazole (0.1%) was found to be effective in reducing the incidence of blast disease and increasing grain yield in finger millet.
RESUMEN
Phytophthora infestans is a pathogen that causes late blight, a major disease of potatoes. The isolation of P. infestans from infected potato plants using agar media has been challenging. This study investigated the use of Rye A and Rye B agar media for the isolation of P. infestans from infected potato tubers collected from the Nilgiris district of Tamil Nadu during 2022. The media were evaluated for hyphal growth, sporangial production, oospore formation, and long-term storage of P. infestans. Phenotypic diagnosis based on cultural and morphological characteristics confirmed the identity of P. infestans. The results were confirmed by a molecular identification test using primers specific to P. infestans. Pathogenicity tests were carried out to assess the virulence of the isolates. This study provides a useful protocol for the selective isolation and characterization of P. infestans, the potato late blight pathogen.