Phosphite has no effect on ectomycorrhizal formation or persistence

Abstract

Phosphite has been successfully used to control Oomycete diseases in a range of horticultural and ornamental crops. In Western Australia, aerial applications of phosphite have been used to protect large areas of native bushland from the devastating soil-borne plant pathogen Phytophthora cinnamomi. However, the effects of phosphite on beneficial microorganisms, such as mycorrhiza, has not been studied in natural ecosystems. In horticultural and agricultural studies, results are contradictory. Phosphite significantly increased vesicular-arbuscular fungi (VAM) in leek, whi1e in maize, it decreased the colonisation of roots and the percentage of onion root length infected. This study investigated the effect of phosphite treatments on three species of early colonising ectomycorrhiza fungi (Laccaria, Pisolithus and Descolea) with Agonis flexuosa, Eucalyptus marginata and E. globulus