Armillaria luteobubalina population structure in horticultural plantings in Victoria, Australia

Abstract

Armillaria luteobubalina was isolated from root-rot of blueberries ( Vaccinium spp.) in three adjacent plantings occupying 0·18–0·23 ha at a site in the Ovens Valley, north-eastern Victoria. Incidence of Armillaria root-rot ranged from 9·4 to 12·7% in these plantings. Eleven somatic incompatibility groups (SIGs) were detected at the site, of which seven occurred amongst 168 diploid isolates from variably disjunct and intermixed regions within one of the plantings. That pieces of infested eucalypt wood, which remained buried following preparation of this previously forested site for planting, were the source of inoculum was evident from the finding of debris outside the plantings infested by some of the same SIGs as those within the plantings. Rhizomorphs were prolific within the plantings and may be more important agents of clonal spread in horticultural settings than in natural forest. Some mating alleles recurred in different SIGs within the plantings but not in other SIGs isolated from a variety of hosts in geographically separated sites around the state. Vaccinium ashei, Protea repens, Protea cynaroides, Actinidia chinensis and Combretum erythrophyllum are reported as new hosts for A. luteobubalina .