Several thousand citrus nematode juveniles can be obtained from 50 ml of soil placed in the top of the funnel. For most other species, soil is usually put through a sieving process to concentrate nematodes and the funnel is utilized as a second step to further clean up the sample. Plant tissue is typically weighed before placing in the funnel and the nematodes reported per gram of tissue. Some labs dry and weigh the roots after extraction and report nematode numbers on a dry weight basis. Mist chambers were developed at UC Riverside as a means to obtain increased recovery of nematodes from plant tissue placed in still another modification of the Baermann funnel.
Overflow water passes over the sides of the culture tube and down the drain.
The length of time materials are left in the chamber varies from lab to lab, typically from 3 to 5 days. With highly motile nematodes such as Aphelenchoides fragariae , it is possible to lose a portion of the sample in the overflow water. At least one laboratory has experienced the problem of clogging of the overflow drain leading to overnight flooding of labs on the floor below. An alternative to misting is jar incubation in which plant tissue is placed in a jar with a small volume of water to keep it moist. This is a simpler procedure but may not recover as many nematodes as misting.