Detection of Armillaria basidiospore dispersal

Abstract

This study used a molecular technique to identify airborne basidiospores caught using a Spore Watch volumetric spore trap in order to understand the nature of basidiospore dispersal by Armillaria novae-zelandiae. The spore trap was deployed during 3 successive years: year 1 within a mature podocarp-hardwood forest containing fruitbodies of A. novae-zelandiae, year 2 in the open at the edge of the forest, and year 3, 150 m from the forest edge. Results indicated that although a high proportion of Armillaria basidiospores were trapped within the forest by screening and reduced air currents, others escaped and were dispersed beyond the stand edge. Year 1 results showed the presence of A. novae-zelandiae on 63% of days while A. novae-zelandiae was recorded on 11% and 20% of days in years 2 and 3, respectively. Sensitivity analysis of the molecular technique that was used indicated that the minimum detectable basidiospore concentration was 1-10 basidiospores/μ1, or about 1 pg/μ1 of DNA.