One method that has been utilized is to place a small quantity of soil infested with a high population of nematodes from another area into a cotton or nylon mesh bag. The bag is then buried in the soil and treatments are applied. At appropriate times following treatments, bags are recovered and analyzed for surviving nematodes. Citrus nematode (Tylenchulus semipenetrans) is one nematode that has been useful as a bioindicator because it has a relatively narrow host range and will typically have several thousand nematodes in 50 ml of soil. It should not be used in fields to be planted to host crops.
This method can be used, for example, to determine the zone of control surrounding a point source injection of a fumigant, as in the example for Telone II in a high organic matter soil. Bags were buried at intervals of 6 inches to 36 inches deep in the soil.
Seeds have been used to determine the effectiveness and depth of penetration of Metam-sodium.
Insects such a mealworms have been used to evaluate the effectiveness of organophosphate and carbamate nematicides.
Earthworms have been placed inside of glass containers with perforated stainless steel lids and buried to evaluate the effectiveness of various fumigant nematicides.