Plant-Parasitic Nematodes Associated with Hop Production in Tasmania, Australia

The abundance, diversity and temporal fluctuations in plant-parasitic nematodes associated with hop production, and their effect on cone yield and levels of alpha acids were assessed in two hop (cv. 'Pride of Ringwood') gardens in Tasmania, Australia within the 1999/2000 season at Forrester River, and within the 2001/2002 season at Gunns Plains. The most abundant plant-parasitic nematode found at both sites was Heterodera humuli Filipjev 1934. Heliocotylenchus dihystera, Pratylenchus spp. and Meloidogyne spp. were present in comparatively low numbers. Temporal fluctuations in the numbers of H. humuli suggested that one generation occurred at Forrester River and Gunns Plains. At Forrester River, the numbers of H. humuli second stage juveniles (J2) on 11 October 1999 were significantly negatively correlated with cone yield on 17 March 2000. No significant correlations were detected between numbers of H. humuli J2 and cone yield at later dates, or between numbers of H. humuli J2 at any sampling date and alpha acid content.