On the methodology of nematode extraction from field samples: baermann funnel modifications.

Routine quantitative nematode extraction for pest management purposes remains a problem. There is need for more knowledge of the parameters limiting efficiency of the various available methods. Sedimentation rates for several species of nematodes have been confirmed as slow and highly variable and therefore not suitable for quantitative separation of nematodes. Funnel losses with clean and unpitted glassware, whether closed or open stemmed, with or without misting, are negligible so long as misting periods are neither inadequate nor excessive; i.e., approximately a 1.5-min water spray period in a 10-min cycle. Tissue paper used to retain soil, sievings, or other substrate in the funnel extraction can greatly inhibit the passage of nematodes depending upon the tissue properties and the nematode species.