Background:

Pleurotus ostreatus and P. pulmonarius produce some toxic metabolites for nematodes, and potentially useful for biocontrol. These compounds are produced in toxocysts.

Objective:

To describe the morphological features of the toxocyst-like structures in vitro produced by Pleurotus ostreatus and P. pulmonarius to contribute to the knowledge of the morphological characters of the genus.

Methods:

Wheat straw, besides malt extract agar (EMA) and potato dextrose agar (PDA) media were used for Pleurotus strains growing. The mycelia were processed for observation through scanning electronic microscopy.

Results and conclusions:

Both species mycelia, on straw and plate culture, produce abundant spherical, stalked structures. Although these structures are morphological similar and look like the toxocysts previously found on these and other species of Pleurotus, they are considered as toxocyst-like structures until the production nematotoxic compounds and their functions being corroborate.