The simplest "field" methods for extractin of nematodes from plants, wood, insects and soil, with additional description how to keep extracted nematodes alive for a long time.

Abstract

The simplest modification of the dynamic extraction method using cottonwool filter based on the Baermann funnel principle, is described. This modification excludes the funnel because a great share of Sticky worms attach to sloping walls of a funnel and thus do not reach the collector Eppendorf tube. But the main principle of the Baermann funnel is used, I. e. sinking down of actively moving heavy narrow bodies via wide holes of filter and thus separating the active worms from passive non-Brownian moving substrate particles, which do not pass the filter and remain above it. This principle is illustrated because it has never been described before. In the proposed modification any sloping walls in the extraction paths are excluded and thus the probability to attach sticky nemotodes to walls is also excluded; only cylindrical equipment with abrupt vertical walls is used; procedures are extremely simplified to be user-friendly for beginners: only filter (cotton pads), Eppendorf tubes, plastic glasses and narrow PVC tubing are applied. The new simplified modification allows one to collect nematodes by non-professional workers, e. g. in Polar expeditions without microscopic study of results. As an addition, an efficient method to maintain extracted nematodes alive is proposed, using the "effect of water film" in foam rubber inside the Eppendorf tube. To maintain nematodes alive during several months it is recommended to suppress bacteria via addition of 0.2-0.4% formaldehyde solution and then keep the tube with nematodes in a refrigerator.