Plant debris of oak forest as soil amendment, to improve the biocontrol activity of Pseudomonas fluorescens and Trichoderma vierns against Meloidogyne javanica, in tomato

Application of antagonistic agents in the rhizosphere of plants is an important approach in control of soil-borne pathogens. Establishment and persistence of biocontrol agents in the soil is a major concern in biological control. This study aimed to determine the effect of plant debris of oak forests on activity of Pseudomonas fluorescens and Trichoderma vierns against Meloidogyne javanica in tomato in green house conditions. In different treatments, both or one of the bioagents were applied to the soil inoculated with M. javanica and amended or unamended with oak plant debris. Based on the results, the growth–related factors of tomato improved in those treatments, in which plant debris were mixed with the soil. In case of nematode-related factors, the number of galls on roots decreased significantly in pots amended with plant debris. Maximum reduction in reproduction factor was observed in treatments with one or both of the biocontrol agents. In comparison to unamended treatments, the rate of reduction in root gall was 56.3% for treatments receiving T. virens and maximum increase in dry weight of root was observed in soils treated with P. fluorescens or T. virens, 68.2% and 56.1%, respectively.