Previous Article | Next Article 
Applied and Environmental Microbiology, October 1998, p. 3846-3853, Vol. 64, No. 10
Laboratory of Phytopathology, Wageningen
Agricultural University, 6700 EE Wageningen, The
Netherlands1;
Department of Plant, Soil
and Entomological Sciences, University of Idaho Research and Extension
Center, Aberdeen, Idaho 831202;
Subdepartment of Mathematics, Wageningen Agricultural
University, 6703 HA Wageningen, The
Netherlands3;
Horticultural Research
International East Malling, West Malling, Kent ME19 6BJ, United
Kingdom4;
Department of Plant Pathology,
University of California, Berkeley, California
947205;
Pest Management Research Centre,
Agriculture and Agrifood Canada, London, Ontario N5V 4T3,
Canada6;
ADAS, Rosemaund, Preston Wynne,
Hereford HR1 3PG, United Kingdom7;
Consejo Superior de Investigaciones Cientificas, Instituto de
Agricultura Sostenible, 14080 Cordoba, Spain8;
Department of Agronomy, Wageningen Agricultural University,
6709 RZ Wageningen, The Netherlands9;
Benaki Phytopathological Institute, 145 61 Kifissia, Athens,
Greece10;
Plant Pathology Research
Station, Charlottetown, Prince Edward Island C1A 7M8,
Canada11;
Department of Botany and
Plant Pathology, Oregon State University, Corvallis, Oregon
97331-290212;
Department of Plant
Pathology, University of Wisconsin, Madison, Wisconsin
5370613;
Department of Plant
Pathology, Ohio Agricultural Research and Development Center, Ohio
State University, Wooster, Ohio
44961-409614; and
GILAT Regional
Experiment Station, M. P. Negev 2, 85280 Israel15
Received 9 April 1998/Accepted 17 July 1998
In a comparison of different methods for estimating
Verticillium dahliae in soil, 14 soil samples were analyzed
in a blinded fashion by 13 research groups in seven countries, using
their preferred methods. One group analyzed only four samples.
Twelve soil samples were naturally infested, and two had known numbers of microsclerotia of V. dahliae added to them. In
addition, a control was included to determine whether transport had an
effect on the results. Results differed considerably among the research groups. There was a 118-fold difference between the groups
with the lowest and highest mean estimates. Results of the other groups were evenly distributed between these extremes. In general, methods based on plating dry soil samples gave higher numbers of V. dahliae than did plating of an aqueous soil suspension. Recovery
of V. dahliae from samples with added microsclerotia varied
from 0 to 59%. Most of the variability within each analysis was at the
petri dish level. The results indicate the necessity to check the
performance of detection assays regularly by comparing recoveries with
other laboratories, using a common set of soil samples. We conclude that wet plating assays are less accurate than dry plating assays.
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Interlaboratory Comparison of Methods To Quantify Microsclerotia
of Verticillium dahliae in Soil
*
Corresponding author. Mailing address: Laboratory of
Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE Wageningen, The Netherlands. Phone: 31 317 483411. Fax: 31 317 483412. E-mail:
aad.termorshuizen{at}medew.fyto.wau.nl.
Applied and Environmental Microbiology, October 1998, p. 3846-3853, Vol. 64, No. 10
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»