Hydroalcoholic Extracts from Pleurotus ostreatus Spent Substrate with Nematocidal Activity against Nacobbus aberrans Phytonematode and the Non-Target Species Panagrellus redivivus

Abstract

Pleurotus ostreatus, an edible mushroom widely consumed worldwide, generates a by-product known as spent mushroom substrate (SMS). This material has demonstrated biological activity against agricultural crop pathogens. In this study, we evaluated the nematocidal effectiveness of hydroalcoholic extracts (T5, T2, AT5, and AT2) derived from SMS of P. ostreatus against (J₂) of the phytonematode Nacobbus aberrans and assessed their potential toxicity towards the non-target nematode Panagrellus redivivus. Among these extracts, AT5 exhibited the highest efficacy against N. aberrans and was the least toxic against P. redivivus. Liquid-liquid partitioning yielded the AQU fraction, which showed significant nematocidal activity against J₂ (75.69% ± 8.99 mortality), comparable to chitosan. The GC-MS analysis revealed the presence of several compounds, including palmitic acid, linoleic acid, and 2,4-Di-tert-butylphenol. These findings are consistent with studies confirming the antagonistic effectiveness of these compounds against phytonematodes. Additionally, all extracts exhibited toxicity against P. redivivus, with T2 being the most toxic. Our findings demonstrate that while the AT5 extract displays antagonistic effectiveness against both N. aberrans and P. redivivus, it was the least toxic among the extracts tested. Thus, SMS of P. ostreatus holds potential as a source of nematocidal compounds, which could offer significant benefits for agricultural pest control.

Keywords: agro-industrial residues; bioactivity; myco-chemical; pest control.

Figure 1

This description explains the visual distinction between living and dead J₂ under a microscope (40× magnification) after treatment with NaOH 1N. Live nematodes appear wavy, while dead ones appear stretched. The specific treatments tested include (a) positive control (chitosan), (b) negative control (water), and two test treatments, where (c) AT5 (10 mg/mL) and (d) AT2 (20 mg/mL) show live and active nematodes.

Figure 2

Effectiveness of AQU fraction (1 mg/mL) and Chitosan (CHI) compound (6 mg/mL) against J₂ and eggs of N. aberrans. The scatter plots indicate the 95% confidence interval. Averages with different letters indicate significant differences (Tukey, p < 0.05). Eggs F_{(2, 15)} = 129.1, p > 0.0001; juveniles (F_{(2, 42)} = 296.8); p > 0.0001.

Figure 3

GC-MS chromatogram of AQU fraction derived from AT5 extract.

Figure 4

(a) Fresh roots infected with N. aberrans; blue arrow shows a knot induced by an adult female (40× magnification); (b) Fresh eggs extracted from the roots; (c) Fresh eggs incubated in distilled water; (d) J₂ hatched.