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Improvements in Assays for Soil Populations, of Pythium ultimum and Macrophomina phaseolina
Author(s) -
Chun D.,
Lockwood J. L.
Publication year - 1985
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1985.tb00623.x
Subject(s) - macrophomina phaseolina , serial dilution , pythium ultimum , petri dish , biology , agar , horticulture , phycomycetes , pythium , agar plate , botany , microbiology and biotechnology , biological pest control , bacteria , medicine , genetics , alternative medicine , pathology , inoculation
The method of S tanghellini and H ancock to enumerate Pythium ultimum Trow, populations in soil was modified by distributing 1 ml dilutions of soil containing the pathogen into 100–120, 2.5 mm diam. Wells made in 2% water agar in 9 × 15 mm Petri dishes. The modified method was more sensitive than the original method m which droplets or soil dilutions are placed on agar, it permitted the use of lower soil dilutions, and was rapidly performed. Sclerotia of Macrophomina phaseolina (Tassi) Goid. (= M. phaseoli [Maubl.] Ashby) were recovered by flotation using 60% sucrose, collected by aspiration onto nylon filters, and surface‐sterilized. The viable Sclerotia were enumerated by counting colonies growing on a selective medium. Efficiency of recovery was 95–97% of Sclerotia added to soil. Large numbers of samples could be processed rapidly by this method which utilized readily available materials, and gave higher counts than earlier methods, which involved only sieving or flotation.