Extraction of <i>Xiphinema</i> and <i>Longidorus</i> species from soil by a modification of Cobb's decanting and sieving technique*

SUMMARY A modification of Cobb's decanting and sieving technique is described which was found to combine speed of operation with efficiency when extracting Xiphinema and Longidorus species from a variety of soils. Standard times were set for sedimentation and the nematodes were collected on a bank of sieves each of 150 μ aperture (rather than of a range of apertures) before final separation from inert debris on a Baermann funnel. Preliminary tests showed that both time and temperature could have considerable effect on yield during the final separation stage. X. diversicaudaturn and X. vuittenezi showed different temperature optima at which the yield was up to twice that at other temperatures. Yields increased markedly with time over the first 20 h, but much less thereafter.