Albino Strains of Ophiostoma Species for Biological Control of Sapstaining Fungi

Summary

Albino strains of Ophiostoma floccosum, O. piceae and O. pluriannulatum were selected and screened for biological control of sapstaining fungi on New Zealand radiata pine (Pinus radiata). Albino strains were obtained through matings and single ascospore isolations from cultures of prevalent species in New Zealand. These strains do not synthesize the melanin-like hyphal pigments of common sapstaining fungi. Additional mating studies were also carried out to obtain isolates of O. piceae and O. floccosum that lacked pigmented fruiting structures. Several albino isolates of O. piceae with colorless synnemata and isolates of O. floccosum with little to no synnemata were obtained. Biological control potential of the albino isolates was evaluated in the laboratory by challenging them on wood chips with fungi that cause extensive sapstain in pine, Leptographium procerum, Ophiostoma piliferum and Sphaeropsis sapinea. Many albino isolates of O. floccosum, O. piceae and O. pluriannulatum were effective in stopping the challenge fungi from staining wood chips and were fast growing and colorless when grown unchallenged on wood chips. Selected albino isolates of O. pluriannulatum were used in two field trials in New Zealand to control sapstain. Several strains were found to significantly reduce dark sapstain as compared to the untreated control logs.