Seasonal fluctuations of the nematode communities in a hop garden soil

Abstract

A study on the seasonal fluctuation of nematode population was conducted during three vegetation periods (2005 – 2007), at 20 and 40 cm soil depth, from May to October, in a hop garden at Nemšová (Slovak Republic). The seasonal fluctuation of the nematode population was related to temperature and rainfall. At 20 cm soil depth of each year, the largest nematode population was recorded in July, and the smallest from July to October. At 40 cm soil depth, nematode abundance was not significantly different between the years 2006 and 2007. In general, at the same depth, a decrease of nematode abundance was observed from May to October. The soil nematode community was rich in bacteriovorous nematodes, especially in the top 20 cm soil. The genus Rhabditis was the eudominant taxon at both soil depths. This genus with the genera Cephalobus, Heterodera, Merlinius and Aglenchus represented the 50 % of the total nematode population at 20 cm soil depth and with the genera Cephalobus, Helicotylenchus, Heterodera and Merlinius represented the 52 % of total nematodes abundance at 40 cm depth.

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

“…Nevertheless, the dominant genera were different. In Slovakia, the genus Rhabditis was the most dominant bacterial feeding nematodes which were further confirmed by Renčo et al (2010a), whereas in Moravia and Bohemia hop gardens the most dominant bacterivore was Acrobeloides. The prevalence of bacterial feeders and plant parasitic nematodes were observed in other agroecosystems as well (Bouwman & Zwart, 1994;Renčo & Valocká, 2002).…”

“…The ability to feed on various food sources, positive reaction to increasing food source and small body size, should be the most important features for explanation of the rich distribution of genus Microdorylaimus through the whole soil profile in our investigated hop gardens. Renčo et al (2010a) established that decreasing abundances of the majority of omnivores and predators during the July were positively correlated with decreasing precipitation and high temperatures. Omnivores and predators have great sensitivity to disturbances (Bongers et al, 1991;Brmež et al, 2006).…”

“…Our data instead reflected a model of gradually decreasing nematode abundance, in which values in individual soil layers and regions overlapped. Nevertheless, it must be taken into consideration that the vertical distribution of nematodes is seasonally changeable (Pen-Mouratov et al, 2003, Renčo et al, 2010a and our study was for technical reasons, carried out as a single survey of localities over two different periods. Other factors that could contribute to insignificant differences in total nematode densities between soil layers are soil cultivation by ploughing, different trophic groups and genera in soil profile that can respond to tillage differently (López-Fando & Bello, 1995) and the interaction with the application of agro-chemicals (Fiskus & Neher, 2002).…”

“…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).…”

Seasonal effects on the population dynamics of soil nematodes in a maize field

“…Genus Rhabditis was markedly eudominant in May and represented almost 80 % of all nematodes, but in September or July its abundance achieved only 8.5 % or 7.8 % of total nematode fauna. Renčo et al (2010) found the highest abundance of Rhabditis in hop-field in June and Venette and Ferris (1997) observed the increase of bacterial feeding nematodes at higher temperature. On the other hand, dominance of C. persegnis, Aphelenchoides minimus, Bitylenchus dubius increased during the season.…”