title: Two semi-automatic elutriators for extracting nematodes and certain fungi from soil.
abstract: Two efficient, semi-automatic elutriators for assaying soil samples for nematodes are described. The first apparatus is a four-unit elutriator which combines conventional extraction methods with the following major features: automatic mixing of 500- to 1,500-cm(3) soil samples with water (+/- air); "turbinate" sample splitters from which fractions of 1/15 or greater are passed onto 26- or 38-microm sieves for collection of larvae and adult nematodes; the capacity for collecting roots, intact egg masses, and cysts on 250-425-microm sieves; and a variable speed motorized sieve-shaker. Nematodes, after being collected on 38-microm sieves, are separated from debris by centrifugation or by Baermann trays. Secondary features include: air cylinders, solenoid valves, and time clock for automatic dumping residual soil and water; relay-controlled coarse spray nozzles activated for 5 sec every 30 sec for washing nematodes through 250-425-mum sieves; adjustable rates of water amt air flow, and tinting. The second type of elutriator operates on similar principles but costs less to construct. It requires somewhat more operator participation; sieve spraying is carried out by the operator, anti elutriators are dumped manually. Both elutriators also show promise for monitoring populations of certain other soil microorganisms.
authors.affiliation: Department of Plant Pathology, North Carolina State University, Raleigh, NC 27607, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Byrd
authors.forename: K R
authors.initials: KR
authors.lastname: Barker
authors.forename: H
authors.initials: H
authors.lastname: Ferris
authors.forename: C J
authors.initials: CJ
authors.lastname: Nusbaum
authors.forename: W E
authors.initials: WE
authors.lastname: Griffin
authors.forename: R H
authors.initials: RH
authors.lastname: Small
authors.forename: C A
authors.initials: CA
authors.lastname: Stone