Detection of Armillaria basidiospore dispersal using molecular techniques

A project is underway to confirm directly the spread of Armillaria into pine plantations by means of basidiospores. Basidiospores of Armillaria novae-zelandiae were trapped from the air using a SporeWatch volumetric spore trap. Between May and August 2005 the spore trap was placed within an undisturbed podocarp-hardwood forest adjacent to a dense cluster of fruitbodies of A. novae-zelandiae on a fallen tree. Trapping was repeated the following year in an open ar ea close to the margin of the same forest. A molecular identification technique was utilised to detect the presence of A. novae-zelandiae basidiospores caught by the spore trap. The technique successfully detected and recorded A. novae-zelandiae basidiospores for a period of 11 weeks during 2005. In 2006 basidiospores were detected for 5 weeks of the testing period at lower quantities, implying filtering of some spores by the tree canopy during dispersal from a more distant spore source. The project is continuing, and this season the spore trap has been placed in the open approximately 1 km from the forest boundary to further test the sensitivity of the technique. Trapping will ultimately be conducted in a pine forest to verify the dispersal of the disease agent by this means.