An ecological study about assemblages of endophytic fungi in Acer macrophyllum in British Columbia: in search of candidate mycoherbicides

Abstract

Healthy 2- to 3-year-old twig pieces with adherent foliage were collected from 3- to 10-year-old Acer macrophyllum at seven sites in coastal British Columbia and examined for the presence of endophytic fungi. Eighty-three percent of the leaves and 52% of the twigs were colonized by endophytic fungi. Fungal assemblages of leaves were dominated by Phomopsis spp., whereas Diplodina acerina was most frequently isolated from twigs. Cryptosporiopsis abietina, Glomerella cingulata (with Colletotrichum gloeosporioides anamorph), and Phomopsis spp. also occurred quite frequently in twigs at some sites. No correlations between weather conditions and any of the endophyte species were detected. Diplodina acerina and G. cingulata were the only two species with a certain potential to be employed as mycoherbicides: D. acerina is distributed over most of its hosts' range, and frequency and density of colonization are high among and within trees and some degree of virulence is present; some formae speciales of G. cingulata are already used as mycoherbicides. Key words: endophytic fungi, mycoherbicides, Diplodina acerina, Colletotrichum, fungal ecology.