The parasitism of Pratylenchus penetrans on native herbaceous and some cultivated plants in Hokkaido.

Abstract

A positive correlation was obtained between the number of eggs and the total nematodes in roots of native herbaceous plants in Hokkaido, and after 2 years of long-term growth a positive correlation was recognized between the number of eggs in roots and the population density of nematodes in soil. In the above investigations, number of eggs or number of nematodes in the roots were used as an index of the nematode reproduction. The plants that had large numbers of eggs and produced high reproduction of nematodes were Agastashe rugosa, Vicia cracca, Thermopsis lupinoides, Lotus corniculatus var. japonicus, and Iris setosa. The plants that were not suitable as a host were Patrinia scabiosifolia, Lysimachia clethroides, Astilbe odontophylla, and Eupatorium makinoi. The rate of nematode population decline on the native species of P. scabiosifolia was superior to the cultivated variety "Wase Ominaeshi". The efficacy depended on the number of eggs in roots. Long term cultivation of Rudbeckia laciniata led to a meager population of nematodes. Rudbeckia hirta also showed a superior reduction of nematodes, as shown in a previous report. Jpn. J. Nematol. 37 (2), 75-86 (2007)