Spent substrate of Pleurotus ostreatus as a nematicide of Nacobbus aberrans in chili pepper (Capsicum annuum) plants

Background/Objetive. The chili pepper (Capsicum annuum) is one of the most important agricultural crops in Mexico. Due to this, the aims were to determine the in vitro effect of the spent substrate by the edible fungus P. ostreatus, strain HEMIM-50, (SSPO) against N. aberrans and evaluate the in situ effectiveness of the SSPO against N. aberrans in chili pepper plants. Material and methods. For the in vitro test, six serial concentrations of the hydroalcoholic extract (SSPO), ranging from 0.62 to 20 mg mL-1 against N. aberrans juveniles. An ANOVA was carried out, followed by Tukey’s means comparison test (p<0.05), adjusted with Schiller-Orelli. For the in situ assay with chili pepper plants, three treatments were evaluated: control (Peat moss), nematicide (Peat moss + Fluopiram) and SSPO (Peat moss 80% + SSPO 20%) and galls, egg masses and eggs per gram of root were measured after 45 days. The data were analyzed using the GLM and LSD tests to compare the means of each treatment. All statistical analyses were analyzed in the Statistical Analysis System program, SAS 9.0. Results. The highest percentage of mortality was obtained with 20 mg mL-1 of the SSPO with a mortality of 98% of mortality and had no significant difference with the positive control with Fluopiram (p<0.05), followed by a mortality of 88.3% with the treatment at 10 mg mL-1. In the in situ evaluation in a combination of Peat moss 80% + SSPO 20%, a reduction of 82% in the number of galls was observed, along with 99% in the mass of eggs and 98% in the number of N. aberrans in comparison with the control with Peat moss. There were no significant differences (0.0b) with the combination of Peat moss + Fluopiram commercial nematicide (Tukey, p<0.05). Conclusion. The spent substrate by P. ostreatus (SSPO) had an in vitro nematocidal activity (98%) against juvenile N. aberrans nematodes; in addition, the input in which the fungus was planted presented a reduction in galls of 82% and 98% for in situ N. aberrans egg mass that infected the chili pepper crop.