Efficacy of different bioagents in suppressing Meloidogyne incognita, and evaluation of some physio-biochemical changes in Phaseolus vulgaris L.

Plant parasitic nematodes cause severe damage, reducing plant production. The ability of four various biocontrol agents was surveyed for effectiveness in inhibiting J2 of Meloidogyne incognita in vitro. The study aims to explore the impact of different bio-agents (Bacillus cereus 54-1, Streptomyces erythrogriesus sub sp. 2, Pleurotus ostreatus, and Spirulina platensis) on the root-knot-nematode, M. incognita reproduction, and their influence on plant growth as well as physiological and biochemical parameters in Phaseolus vulgaris L. plants under greenhouse conditions. Effective inoculation of four bio-control agents on growth and physio-biochemical parameters of bean plants infected with root-knot-nematode was also investigated. After 48 hours of exposure to bioagents, mortality was caused by M. incognita J2s. Mortality ranged between 67.3 and 89%. Under experimental conditions, further validating the relative efficacy of different bioagents in control M. incognita on common bean in two successive seasons. All pageants were efficient in preventing nematode reproduction, but with varying efficacy. Oxamyl (Nematicide) was an extremely effective treatment for suppressing total nematode populations. Nevertheless, the second most effective treatment for reducing M. incognita in roots and soil was B. cereus. All treatments significantly enhanced growth as compared to the control. Treatments with four bioagents significantly reduced H2O2 and malondialdehyde levels. While it significantly raised the activity of peroxidase, polyphenol-oxidase, and superoxide dismutase, in addition to raising the content of phenolics and flavonoids in the infected common bean. The tested bioagents were efficient in preventing nematode reproduction, but at various levels of efficacy. In addition, all treatments significantly enhanced common bean growth parameters and reduced the levels of both H2O2 and MDA. While it raised the activity of POD, PPO, SOD, and contents of phenolics and flavonoids in the infected common bean. These results highlight the value of bioagents as a promising biocontrol technique to manage root-knot-nematodes in common beans.