Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Tylenchulus semipenetrans

[ref. ID; 4641]

Test system

Strains

Mixed life stages of T. semipenetrans were extracted from soil from an infested olive orchard in Orland, CA by decanting and sieving soil. Nematodes were collected after 24 hr and used immediately.

Toxicants

Isothiocyanate (ITC)-producing glucosinolates (Sinigrin: precursor to allyl ITC, Glucotropeolin: precursor to benzyl ITC, Sinalbin: precursor to p-hydroxybenzyl ITC, Gluconasturtiin: precursor to 2-phenyethyl ITC, Glucoraphanin: precursor to 4-methylsulphinylbutyl ITC).
The glucosinolates are derived plant materials (Brassica hirta 'Martegena', Brassica juncea 'Pacific Gold', Broccoli (B. oleracea var. botrytis: low-glucosinolate plant), wheat (Triticum aestivum: non-glucosinolate plant)).

Test design

Twelve cubic centimeters soil (Yolo sandy loam (40% sand, 43% silt, 18% clay, 1.85% organic matter, and pH 7.3): Sustainable Agriculture Farming Systems Project, Agronomy Farm, University of California, Davis, CA, USA), with or without amendment, was placed into a 20-ml scintillation vial in three aliquots; the soil packed after each addition. The vials were hydrated to stimulate the production of ITCs. Assay nematodes (200-300) were inoculated in 1 ml water into a depression in the center of the soil in each vial. Water was added to the vials to achieve a soil moisture level approximately 60% of field capacity. The vials were closed to prevent loss of volatile ITCs and incubated for 72 hr at 25 degrees C. 5 replications.

Measurements

Mortality.