Evaluation of the Efficacy of a Local Isolate of the Fungus Beauveria bassiana in Colonizing Eggplant Plants in vitro and Promoting its Growth to Reduce its Infection with the Root-Knot Nematode, Meloidogyne, spp.

Abstract

In the global effort to reduce reliance on chemical pesticides for pest control, the entomopathogenic fungus Beauveria bassiana (Bals.) Vuil. is gaining recognition as an economical and environment-friendly alternative. This fungus has traditionally been sprayed directly onto the plant’s aerial parts, but more recently, its introduction into plant tissues as an endophyte using various inoculation techniques is being investigated. This research aimed to investigate, in the laboratory, the efficiency of a local isolate of B. bassiana in the colonization of eggplant plants by inoculating them through immersing their roots in the fungal spore suspension, as well as the isolate’s capacity to promote plant growth and protect it against the infection with the root-knot nematode Meloidogyne spp. The endophytic isolate N19 of B. bassiana was used. The experiment was carried out through five treatments: control treatment, plant inoculation with the fungus only, plant infected with nematodes only, plant inoculation with the fungus before nematode infection, and plant infected with nematodes before fungal inoculation. Egg masses and the number of galls formed on the roots due to infection with root-knot nematodes were counted two months after treatment. Plant height, root length, and fresh weight of both the shoot and the root of the plant were measured. Fungal colonization of roots, stems, and leaves was evaluated. The results obtained showed the ability of the fungal isolate used to grow endophytically in the stems, leaves, and roots of eggplant in the laboratory without any significant role in increasing plant growth indicators. There was a significant effect of B. bassiana in reducing the number of nematode galls and egg masses on eggplant roots. The reduction rate reached 85.8 and 83.19%, respectively. These results showed that the application of B. bassiana as an endophyte is a promising approach in protecting eggplant plants from infection with root-knot nematodes, which encourages further evaluation of the fungal efficiency under field conditions.

Keywords:

Biological control, insect pathogens, fungal endophytes, Beauveria bassiana, root-knot nematode, Meloidogyne.