Control of Meloidogyne javanica with Pleurotus djamor spent mushroom substrate

Abstract

Abstract Background The interest in the development of products that cause less damage to the environment associated with the loss of efficiency of chemical nematicides for the control management of nematodes is growing. Thus, the adoption of biological control or the use of biopesticides are excellent options for these products like those based on chemical compounds, such as commercial pesticides and anthelmintic (AH) drugs. Spent mushroom substrate (SMS), a product of the mushroom production industry, has great potential for biological control due to its high levels of mycelium, residual enzymes, high humidity and unique microbiota that may contain other nematode antagonists. For this reason, this study aimed to evaluate the potential of spent mushroom substrate (SMS) from Pleurotus djamor cultivation in the control of Meloidogyne javanica in lettuce and assess its effects on plant resistance enzymes and soil biological activity. Results SMS reduced by 98.68% the nematode reproduction, and a plateau was reached at SMS concentrations above 15%. For the population density of nematode (nematode g-1 root), this reduction was 99,75%. Higher concentrations of SMS caused phytotoxicity in lettuce, with reduction of vegetative variables, chlorophyll content and nitrogen balance in the leaves; however, SMS increased the anthocyanin content. Guaiacol peroxidase activity was the highest in treatments containing 0% and 30% SMS and phenylalanine ammonia-lyase activity was the highest in the 60% SMS treatment, suggesting induction of resistance to M. javanica. The maximum soil basal respiration was estimated to be achieved with 25.75% SMS, whereas the maximum soil metabolic quotient was estimated to be achieved with 8.8% SMS. Soil biomass carbon increased with increasing SMS proportion. Conclusions Spent substrate from P. djamor cultivation incorporated in soil at proportions of 15, 30, 45 and 60% is efficient in controlling M. javanica in lettuce. Graphical Abstract