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

Abstract

A total of 61 nematode species belonging into 48 genera was identified in soil of nine localities of hop gardens in Slovakia. From free living soil nematodes the most abundant were the genus Rhabditis -eudominant taxon, species Aphelenchus avenae -dominant taxon, the species Cephalobus persegnis, Chiloplacus propinquus, Aglenchus agricola, Nothotylenchus acris, Aporcelaimellus obtusicaudatus and genus Eudorylaimus were subdominant taxa. Only ten species of plant parasitic nematodes were observedDitylenchus dipsaci, Bitylenchus dubius, Merlinius brevidens, Rotylenchus robustus, Helicotylenchus canadensis, H. digonicus, Pratylenchus penetrans, P. pratensis, Heterodera humuli, and Paratylenchus bukowinensis. Bitylenchus dubius and Merlinius brevidens belonged to dominant taxa, the species Heterodera humuli and Helicotylenchus digonicus to subdominant taxa. The occurrence of Heterodera humuli cysts was recorded at all localities studied, and the occurrence of H. humuli larvae in soil during autumn indicates that possibly more than one generation of the parasite have developed within one vegetation period. The proportion of individual trophic groups in nematode communities of hop gardens was characterised by the prevalence of bacterial feeders followed by plant parasites. The ecological characteristics used for ecological evaluation, especially Maturity Index and Plant Parasitic Index/ Maturity Index, indicate a more disturbed environment. Although hop is a perennial plant, the structure and ecology of its nematode communities is more similar to the agricultural ecosystems with a higher level of agricultural practices.Key words: nematode communities; hop gardens; Slovakia IntroductionThe wild hop, Humulus lupulus L., can be found freely in nature; commercial hop cultivars used for beer production ………….are grown in suitable climatic and soil conditions throughout the world. The first records of nematodes in soil of hop fields were associated with the occurrence of Heterodera humuli in Germany Voigt (1894) and, subsequently, in England (Percival, 1895). To date, research on nematodes linked with hops had focused mainly on this speciesconsidered to be the dominant parasite of hop. Previous investigations studied the geographical distribution of H. humuli e.g. in the Czech Republic (Šály & Kříž, 1961), in Switzerland (Hogger, 1988), in Spain Lopez -Robles (1995), in England (Mende & McNamara (1995a), in Germany (Eppler, 1999), explored the biology and a life cycle of H. humuli (Mende & McNamara (1995a,b), pathological effect of H. humuli on hop plants connected with different varieties (Mende & Mc. Namara, 1995b;Hafez et al., 1999), and nematodes as vectors of plant viruses by e.g. 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 ...

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

“…The prevalence of bacterivores in hop gardens studied may be caused by regular fertilization with manure per each 2 -3 years and with industrial fertilizers each year. This result is similar to those published by Lišková and Renčo (2007). The manner of decomposition of organic matter can be evaluated by B/F index, which is focused on the dominant way of decomposition either by bacteria or fungi.…”

“…A similar trophic structure of nematodes was also found in hop gardens in Slovakia (Lišková & Renčo, 2007). Nevertheless, the dominant genera were different.…”

“…Nematode vectors of plant viruses in hops were studied by Valdez et al (1974) and McNamara and Eppler (1989). Lišková and Renčo (2007) and Renčo et al (2010a) published detailed information on the composition and seasonal fluctuation of nematode communities in hop gardens in Slovakia. The first record of H. humuli in Czech literature was published by Hrabě (1954), a branding of this nematode as a pest comes from Šály and Kříž (1961).…”

Aphelenchus avenae (Nematoda: Aphelenchidae) under the rhizosphere of Brassica napus

“…It is a cosmopolitan species. In the neighbouring countries of the Czech Republic it was recorded from Slovakia (Lišková & Renčo, 2007), Germany (Decker, 1988), Poland and Austria (Andrássy, 2007). In the Czech Republic it was recorded by Háněl (2000a;2000b).…”

Using of hydrogen cyanide against Ditylenchus dipsaci nematode present on garlic

“…Another crops e.g. hop could be also affected (Lišková and Renčo 2007). Therefore, treatment of the seed plant material is of the key importance and is routinely performed before planting (Hanks and Linfield 1999).…”