Effect of endophytic colonisation of entomopathogenic beauveria bassiana(Balsamo) on two spotted spider mite tetranychus urticae (Koch) in tomato

Abstract

An experiment was carried out to artificially establish the entomopathogenic fungus Beauveria bassiana inside the tomato seedlings through various methods of inoculation i.e. foliar spray, soil drenching and seed soaking and to evaluate its endophytic effect on Tetranychus urticae. The % colonisation was recorded after 15 and 30 days after post inoculation (DAPI) through surface sterilisation and isolation technique for all the inoculation methods. In roots, colonisation of B. bassiana was high in soil drench (46 and 34%) followed by seed soaking (38 and 36%) and poor in foliar spray (10 and 4%), while in stem, the colonisation was high in foliar spray (44 and 40%) followed by seed soaking (40 and 30%) and soil drenching (26 and 26%) at 15 DAPI and 30 DAPI, respectively. In leaf, colonisation frequency was high in foliar sprayed (50 and 56%) followed by soil drenching (30 and 8%) and seed soaking (10 and 8%), at 15 and 30 DAPI respectively. Leaf detachment bioassay showed that mortality of T. urticae was significantly higher in foliar sprayed leaf (83.33 ± 7.6%) followed by soil drenching (73.33 ± 7.6%) and seed soaking (65.00 ± 10%) compared to control plants (3.33 ± 0.5%). These results suggest that B. bassiana could colonise as endophyte and also have potential to protect plant from phytophagous mites.