Selection of entomopathogenic fungi Isaria javanica FT333 for dual control of thrips and anthracnose

 Moran Lee, Hyeju Jeong, Jaeyoon Kim, Dayeon Kim, Seung Ho Ahn, SangYeob Lee, Ji Hee Han**   

1Agricultural Microbiology Division, National Institutes of Agricultural Science, Wanju 55365, Korea

Abstract

Red pepper is seriously damaged by thrips (Thrips palmi) and anthracnose caused by Colletotrichum acutatum throughout its development. Because of biotic constraints, producers often depend on chemicals that are expensive and have adverse effects on the environment, operator, and beneficial insects. In addition, resistance is developed because of the repeated use of chemicals. In recent decades, the use of microorganisms in crop protection has become a credible alternative because it is eco-friendly. In this study, we aimed to select isolates with insecticidal and fungicidal activities against the pathogens that cause anthracnose and thrips. We treated T. palmi adults and juveniles with 13 strains of entomopathogenic fungi (isolated from the soil by using the insect-bait method), and 6 strains showed excellent insecticidal activity (70–100%) 5 days after the treatment. The selected isolates were cultured with C. acutatum to screen for the strain with excellent anti-fungal activities, and the isolate FT333 showed more than 95% control efficacy against C. acutatum in vitro. The isolate was identified as Isaria javanica through its morphological characteristics and phylogenetic analysis of the ITS and β-tubulin nucleotide sequences. The Isaria javanica FT333 isolate could be used effectively for dual bio-control of thrips and anthracnose during red pepper cultivation.

Acknowledgements

This study was supported by the research grant (PJ01250601) of Rural Development Administration (RDA) of Korea

Figures & Tables

Fig. 1. Control efficacy of first selected isolates against juvenile of thrips. Control was treated with 0.02% Tween 80 (mean ± SE). Spores were observed in the mu㎜ies after bioassay. Data were analyzed using ANOVA ( < 0.001), and the differences were further elucidated using DUNCAN’s multiple range test. Different letters indicate significant differences at < 0.001 at each time point