Establishment of the fungal entomopathogen Beauveria bassiana as an endophyte in sugarcane, Saccharum officinarum

We investigated the ability of the fungal entomopathogen Beauveria bassiana strain GHA to endophytically colonize sugarcane (Saccharum officinarum) and its impact on plant growth. We used foliar spray, stem injection, and soil drench inoculation methods. All three inoculation methods resulted in B. bassiana colonizing sugarcane tissues. Extent of fungal colonization differed significantly with inoculation method (χ2 = 20.112, d. f. = 2, p < 0.001), and stem injection showed the highest colonization level followed by foliar spray and root drench. Extent of fungal colonization differed significantly with plant part (χ2 = 33.072, d. f. = 5, p < 0.001); stem injection resulted in B. bassiana colonization of the stem and to some extent leaves; foliar spray resulted in colonization of leaves and to some extent, the stem; and soil drench resulted in colonization of roots and to some extent the stem. Irrespective of inoculation method, B. bassiana colonization was 2.8 times lower at 14-16 d post inoculation (DPI) than at 7-10 DPI (p = 0.020). Spraying leaves and drenching the soil with B. bassiana significantly (p = 0.01) enhanced numbers of sett roots. This study demonstrates for the first time that B. bassiana can endophytically colonize sugarcane plants and enhance the root sett and it provides a starting point for exploring the use of this fungus as an endophyte in management of sugarcane pests.