Colonization of Beauveria bassiana (Balsamo) Vuillemin strains in maize (Zea mays L.) and their efficacy against stem borer Chilo partellus (Swinhoe)

Abstract

Glasshouse experiments were conducted to study the endophytic ability of six strains of entomopathogenic fungus Beauveria bassiana in maize leaf and stem tissues when applied through foliar sprays of oil formulations. B. bassiana treated and untreated control plants were artificially infested with second instar larvae of Chilo partellus to assess the stem borer damage. All six strains showed varying percent colonization and persistence in stem and leaf tissues. The mean percent colonization ranged from 16.67-46.67 % in older stem tissues and 22.22-52.22 % in young stem tissues and in leaf, it ranged from 25.56-47.78 % in older leaf tissues and 31.11-57.78 % in young leaf tissues. Among six isolates tested, Bb-45 isolate recorded the maximum mean colonization in older stem (46.67 %), older leaf (47.78%) and in young stem (52.22 %). Bb-5a isolate showed maximum mean colonization in young leaf tissues (57.78 %). Significantly lower percentage of dead hearts (2.2-11.1%) and lower stem tunneling (2.7-4.3cm/plant) was observed in B. bassiana treated plants as compared to the untreated control plants (28.86% of dead hearts and 13.41cm/plant stem tunneling).