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18Russian Journal of Nematology, 2011, 19 (1), 93 - 100
Soil amendments with Streptomyces lydicus WYEC108 and chitin against the northern root-knot nematode, Meloidogyne hapla Chitwood, on
tomato
Guy Belair, Nathalie Dauphinais and Guy Jobin
Horticulture Research and Development Centre, Agriculture and Agri-Food Canada, St-Jean-sur-Richelieu, Quebec, Canada; e-mail: guy.belair@agr.gc.ca
Accepted for publication 6 January 2011
Summary. Actinovate® SP and Actino-Iron®, two commercial formulations of the antagonist streptomycete strain Streptomyces lydicus WYEC108, were first tested singly or in combination with chitin against Meloidogyne hapla juveniles in a plant-less test. The best nematicidal treatment was the joint application of Actinovate and chitin at 1.0% (w/w), which significantly reduced by 95% the mean number of M. hapla as compared with the control. In two glasshouse bioassays, the joint application of Actinovate and chitin at 1.0% was again the best treatment and reduced the mean number of infective juveniles per pot by 73% (trial 1) and 98% (trial 2) compared with the control. This soil treatment also reduced the mean number of galls per pot by 81% (trial 1) and 99% (trial 2) compared with the control. However, the high variability and high costs of these soil treatments are major obstacles for them to become viable alternatives for the management of M. hapla on tomato.
Key words: Actino-Iron®, Actinovate® SP, biological control, chitin, Solanum lycopersicon, soil amendment.
In Quebec, the northern root-knot nematode Meloidogyne hapla is a nematode pest of organically grown tomato under glasshouse conditions. Currently, this production is small but it is rapidly expanding with the increased demand from consumers (Carrier, 2008). This industry cannot rely on pesticides but would be allowed to use organic amendments of all sorts to manage this pest. In some production system, organic soil amendments and biological control agents have been proposed as the main elements of integrated management of plant-parasitic nematodes (Oka et al., 2000). Some successes in the biological control of plant-parasitic nematodes have been achieved with fungi Paecilomyces lilacinus strain 251 (Holland et al., 1999; Schenck, 2004) and Trichoderma harzianum (Reddy et al., 1996; Rao et al., 1998; Sharon et al., 2001) and with bacteria Pasteuria penetrans (Chen et al., 1996, 1997; Jonathan et al., 2000), Streptomyces spp. (Samac & Kinkel, 2001) and Gluconacetobacter diazotrophicus (Bansal et al., 2005). A collagenolytic enzyme isolated from Bacillus cereus
digested collagens extracted from intact cuticles of second-stage juveniles (J2) of the root-knot nematode M. javanica and thus proved its ability to damage nematode cuticles (Sela et al., 1998). Similarly, P. lilacinus was cultured in liquid media wherein production of proteases and chitinases was induced by the addition of egg yolk and chitin, respectively. However, their capacity to degrade chitin-containing eggs and collagen-containing cuticles was not tested (Khan et al., 2003). It is probable that chitinolytic behaviour of fungal strains isolated from cysts of Heterodera glycines was correlated with their capacity to parasitise eggs of H. glycines andM. arenaria (Godoy et al., 1982).
Organic amendments were proposed as a way to increase nematicidal activity of soil microflora (Kerry, 2000). The rationale is to amend the soil with a molecule identical or structurally related to the one constituting the outer layers of a pathogen (Mitchell & Alexander, 1961). Such a strategy is believed to increase the proportion of soil microflora responsible for nematicidal activity. For example, galling of tomato roots caused by M.
