THE PRESENCE AND ANTIFEEDANT FUNCTION OF TOXIN-PRODUCING SECRETORY-CELLS ON HYPHAE OF THE LAWN-INHABITING AGARIC CONOCYBE LACTEA

On water agar, Conocybe lactea (Lange) Metrod produces droplets of tox in on conspicuous secretory cells. Both free-living rhabditoid nematod es and fungus-feeding nematodes (Aphelenchoides sp.) are immobilized w hen they contact the toxin droplets. Prolonged and (or) repeated expos ure to the toxin results in death of the nematodes, which may take pla ce at some distance from the contact point. Unlike Pleurotus ostreatus (Jacq.:Fr.) Kummer, the hyphae of C. lactea do not locate and coloniz e immobilized nematodes and (or) consume them as a nutrient source. It is considered that the toxin droplets are for protection of the hypha l system and function as antifeedants to repel or kill fungus-feeding nematodes and possibly other fungus-feeding soil microfauna. No differ ences were observed in nematode response between dikaryotic and monoka ryotic cultures, although the latter produced a spermatial-like arthro sporic anamorph. Panaeolina foenisecii (Pers.:Fr.) R. Maire also produ ces secretory cells with fluid droplets. These droplets, however, are not as toxic to nematodes as those of C. lactea.