Prospects of endophytic fungal entomopathogens as biocontrol and plant growth promoting agents: An insight on how artificial inoculation methods affect endophytic colonization of host plants

Entomopathogenic fungi (EPF) can be established as endophytes in the host plants to offer a long-term preventive measure for pests and diseases. This practice serves as a better alternative to the common practice of periodic direct application of EPF on plants or the target pests as a short-term defense strategy against pests and diseases. These fungal endophytes, aside from their role in pests and diseases prevention, also act as plant growth promoters. Several fungal endophytes have been associated with improvement in plant height, dry and wet weight and other growth parameters. However, many limiting factors have been identified as mitigating the successful colonization of the host plants by EPF. The inoculation methods used have been identified as one, but sadly, this has received little or less attention. Some previous studies carried out comparison between various artificial inoculation methods; foliar application, seedling dipping, soil drenching, seed inoculation, direct injection and others. In separate studies, some authors had suggested different application methods that are best suitable for certain fungal entomopathogens. For instance, leaf inoculation with conidial suspensions was suggested to be the best inoculation method for Beauveria bassiana in sorghum, stem injection was suggested as the most suitable for coffee, while, root dipping method proved the most successful for B. bassiana colonization of tomato plants for the management of Helicoverim armigera. Here, we discussed entomopathogenic fungal endophytes as bio-control agents, plant growth promoters and highlighted the effect of various artificial inoculation methods on their endophytic colonization of the host plants.