Factors Influencing the Extraction of Nematodes From Soil

Using a modification of the Baermann funnel technique, duplicate soil samples were processed concurrently at St Coombs (1370 m elevation) and Colombo (sea level). The number of Pratylenchus loosi extracted at Colombo was only 14% of those extracted at St Coombs. Experimental results indicate that this difference is due to the temperature difference between the two locations. The number of P. loosi and other nematodes extracted from soil is markedly reduced by temperatures of 27°- 35° C during the extraction process. Storing soil at 31° and 35° prior to extraction, also restricts the number of P. loosi extracted. Soil storage and nematode extraction at 31 ° gave the same effect as extracting nematodes in Colombo. Other factors influencing the number of nematodes extracted are the sieves used in the extraction process and the time between sampling and processing the soil.