Albino Strains of Ophiostoma Species for Biological Control of Sapstaining Fungi

Abstract

SummaryAlbino strains ofOphiostoma floccosum,O. piceaeandO. pluriannulatumwere 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 ofO. piceaeandO. floccosumthat lacked pigmented fruiting structures. Several albino isolates ofO. piceaewith colorless synnemata and isolates ofO. floccosumwith 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 piliferumandSphaeropsis sapinea. Many albino isolates ofO. floccosum,O. piceaeandO. pluriannulatumwere 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 ofO. pluriannulatumwere 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.