An Elutriation Method for Quantitative Isolation of Cylindrocladium crotalariae Microsclerotia from Peanut Field Soil

Publisher Website
Google Scholar
Abstract
Plant [peanut, Arachis hypogaea] debris and microsclerotia of C. crotalariae were elutriated from soil using a semi-automatic elutriator which was designed for separating nematodes from soil. Plant debris (425 .mu.m) and microsclerotia-size particles (38-425 .mu.m) in soil were collected on 425 and 38 .mu.m sieves, respectively. Plant debris from the 425 .mu.m sieve was blended for 2 min in H2O then concentrated on a 38 .mu.m sieve. Each sieve residue was treated for 1 min in 0.25% NaClO. After rinsing, the sieve residues were suspended in H2O and 5 ml subsamples were pipetted into 100 ml of an isolation medium at 45.degree. C. The medium then was mixed and poured into 10 petri dishes. The isolation medium contained glucose, 15 g; KNO3, 0.5 g; yeast extract, 0.5 g; KH2PO4, 1 g; MgSO .times. 7H2O, 0.5 g; Tergitol (NPX), 1 ml; thiabendazole, 1 mg; chloramphenicol, 100 mg; chlortetracycline, 40 mg; and 20 g agar/l of H2O. After 5 days of incubation, the presence of brown microsclerotia and asexual sporulation permitted recognition and counting of C. crotalariae colonies in assay plates. The elutriation and enumeration procedure was effective in recovery of at least 91% of laboratory-grown microsclerotia in artificially infested soil. Numbers of microsclerotia in 23 naturally-infested, peanut field soils ranged 0.2-72/g soil.

This publication has 1 reference indexed in Scilit: