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(09-07) Effects of trace metals on entomopathogenic nematodes. Jaworska, Magdalena*,1, Tomasik, Piotr1, Ropek, Dariusz1, 1 Agricultural University, Al. Mickiewicza 21, Krakow, Poland ABSTRACT- Heavy metals are very toxic to living organisms. But a high concentration of heavy metals in soil not necessarily is environmentally toxic. Only mobile, soluble forms of heavy metals are available for soil microrganisms. The effect of single and pair metal ions on movement, mortality and infectivity of entomopathogenic nematodes was studied in laboratory conditions. Only aqueous solutions of soluble salts were used in the experiments. Entomopathogenic nematodes of the Steinernema and Heterorhabditis genera are promising alternatives to synthetic insecticides. Many abiotic soil components affect nematode activity, dispersal and host finding, among them are metal ions. Biological activity of metal ions has been observed in flora and fauna but very little experimental work, mainly for particular species of plant parasitic nematodes has been done on the subject. There is a strong resistance of both genera to metal ions as long as the mortality of the organisms is taken into account. However, heavy metal ions lowered infectivity of nematodes with respect to wax moth caterpillars, Galleria mellonella. Tree metal ions Pb (II), Zn and Cu(II), caused considerable toxicity to nematodes. Mn (II) and Mg ions not only suppressed the mortality from heavy metal ions but also showed strong stimulating properties for the nematodes. Both ions reduced the nematode mortality and increased their infectivity. At certain pH metal cations after ligation may enter complex metal anions. Their toxicity as well as mechanism of their action on various organisms might be entirely different. Complex anions of Al, Fe (II) or Zn are more toxic than their cations. Derivatives of starch dialdehyde can be applied as agents, which immobilise heavy metal ions in soil. These complexons protected nematodes from the toxic effect of metal ions in aqueous solutions. Key words: metal ions, nematodes |
