Abstract
A modification of the sieve funnel technique (SF-T) was examined for its efficiency to separate Meloidogyne incognita larvae and Helicotylenchus sp. in comparison with that of the double layers centrifugal-flotation method (DLC-M). Following to remove the water from the nematode suspension by a thin layer of absorbent cotton sandwiched between sheets of Japanese paper, it was settled in the Baermann funnel for 72 hr at 20°C. As the results, it was considered that the efficiency of SF-T in August was similar to that of DLC-M for M. incognita larvae and was higher than that for Helicotylenchus sp. When expressed by CV, the variability of numbers of M. incognita larvae extracted was regarded as about 10%. The motility of M. incognita larvae decreased during winter but recovered after the incubation at 20°C for 48-72 hr. Such a decrease in the motility in winter did not appear for Helicotylenchus sp. In soil, a considerable proportion of M. incognita larvae died or was dying in winter and early in spring, but comparatively fewer Helicotylenchus sp. did in, that season. This method can be used for the quantitaive estimation of the.living larvae of M. incognita in soil without any effect of temperature on the motility, of the, nematode.
