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

Abstract

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.

Communities of free living and plant parasitic nematodes in hop gardens in Slovakia

“…This is in agreement with the assumption of the development of two or three generations of H. humuli in England (Mende & McNamara, 1995a). According to Brown et al (1993) and Hay and Pethybridge (2003), hop has a solid capacity to tolerate nematode feeding, but research by Mende and McNamara (1995b), Hafez et al (1999) and by Hay and Pethybridge (2003) has shown that at high population density of H. humuli, when infested plants are under stress from drought or from other pathogens, the high population density can adversely affect losses of hop production. In spite of a low number of plant parasitic species observed in Slovakian hop gardens, population density and frequency of the species Bitylenchus dubius and Merlinius brevidens was high nearly at all localities and, together with H. humuli, these nematodes can be a potential factor negatively influencing hop growing in Slovakia.…”

“…Valdez et al (1974) and Barbez (1982). The other nematodes of the rhizosphere of hop gardens were investigated by Malan et al (1991), Eppler (1999), and Hay and Pethybridge (2003 and others. In spite of the substantial investigation of communities of free living and plant parasitic nematodes of various agroecosystems and natural ecosystems in Slovakia, no data from hop gardens are available -with the exception of the reports on the occurrence of H. humuli in Slovakia by Šály (1983), but with no closer reference to the habitat.…”

Composition and vertical distribution of free living and plant parasitic nematodes in hop gardens in the Czech Republic

“…The association of Meloidogyne spp. with hop was recorded in Tasmania (Hay & Pethybridge, 2003) and M. hapla in USA (Maggenti, 1962), should be an alarm signal for Czech hop production because of widely spread M. hapla in the Province of Central Bohemia (Zouhar et al, 2003). Nevertheless, the very low abundance of predators and omnivores in the hop gardens studied can be interpreted as a sign of negative influence of agricultural practices upon soil nematode communities (Wasilewska, 1997).…”

“…Hay and Close (1992) refer species Xiphinema diversicaudatum from hop gardens in New Zealand. No one is referred from Slovakia or from Tasmania (Lišk-ová & Renčo, 2007;Hay & Pethybridge, 2003). The low occurrence of virus-vector nematode species in Czech hop gardens in comparisons with Czech vineyards or fruit orchards (Erbenová, 1975;Kumari, 2006) can be explained (as in the case of Criconematidae) by the different sorts and types of soil, the low number of soil samples or nonsuitable sampling patterns for virus-vector nematodes.…”

“…The nematode communities in hop gardens were more extensively investigated by Hay & Pethybridge (2003) in Tasmania, by Eppler (1999) in Germany and by Malan et al (1991) in the South Africa. Nematode vectors of plant viruses in hops were studied by Valdez et al (1974) and McNamara and Eppler (1989).…”