Biological control of stump sprouting of broadleaf species in rights-of-way with Chondrostereum purpureum: incidence of the disease on nontarget hosts
1999
Gosselin, L. | Jobidon, R. | Bernier, L.
The mass inoculation of Chondrostereum purpureum to control stump sprouting of woody species raises concerns regarding the potential increase of silverleaf disease. To assess this risk, two studies were conducted on the periphery of four experimental sites where two native strains of C. purpureum were deployed. The first study assessed the occurrence of sporophores along transects of 1.6 km surrounding each site. The second study examined the presence of the two deployed strains of C. purpureum in the tissues of susceptible stumps adjacent to the experimental sites. Two molecular markers, one diagnostic to each strain, were developed using random amplified polymorphic DNA (RAPD) analysis. Silverleaf disease incidence was generally low over a 2-year evaluation period. Across transects, 0.3% of the trees examined bore C. purpureum sporophores. A higher incidence (15%) of the disease was observed among the 220 cut trees sampled. Frequency of infection among sampling plots varied from 0 to 45%. However, RAPD analysis determined that at least 85% of these infections were not attributable to deployed strains of C. purpureum. This showed that added infection originated mainly from naturally occurring sources of inoculum and supports a minimal risk scenario to forest trees.
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