Chitin-based bioformulation of Beauveria bassiana and Pseudomonas fluorescens for improved control of leafminer and collar rot in groundnut

The talc-based formulation of Beauveria bassiana (B2 and B4) and Pseudomonas fluorescens (TDK1 and Pf1) strains and its mixture amended with and without chitin were developed and tested for their efficacy against the leafminer insect pest (Aproaerema modicella) and collar rot (or) seedling blight pathogen (Sclerotium rolfsii) in groundnut under glasshouse and field conditions. Application of talc-based formulation of B2 + TDK1 + Pf1 strains mixture (amended with or without chitin) through seed, soil and foliar spray effectively reduced the incidence of leafminer and collar rot in groundnut compared to individual bioformulation and control treatments both under glasshouse and field conditions. Groundnut leaves when treated with this bioformulation mixture, altered the feeding behavior of leafminer larvae and increased larval mortality under in vitro. Further, a significant increase in growth parameters and yield were observed in groundnut plants treated with B2 + TDK1 + Pf1 compared to individual bioformulation and untreated control. Increased accumulation of chitinase enzyme was observed in groundnut plants treated with mixture of B2 + TDK1 + Pf1 against A. modicella and S. rolfsii when compared to other treatments. (C) 2010 Elsevier Ltd. All rights reserved.