Publication Date

1980

Document Type

Report

DAFWA Collections

Grains and field crops

Abstract

Contents: A. Inoculum of the take-all fungus and the prediction of take-all. 1. Time of sampling 1a Newdegate 1b Badgingarra 1c Kulin 2. Inoculum from grass and wheat residues - Esperance. 3. Hypovirulent strains and control of take-all 3a Esperance, 3b Newdegate. Results from the preliminary studies which commenced in 1978 have shown several interesting trends in the behaviour of the field inoculum of the take-all fungus (TAF). "Disease severity Assay" has emerged as a potentially useful assay of field soil. This assay reflects the level of disease severity (on a 0-5 scale) caused by the resident inoculum of the TAF in the soil. For the assay wheat seedlings are grown under an environment conducive to the disease. The propagule numbers were estimated by the Most Probable Number (MPN) technique, and those capable of producing necrosis > 5mm on main root axes are considered to be 'effective', as compared to the 'total' numbers which include both these units as well as those capable of causing stelar discoloration only of fine lateral roots or abortive lesions on main axes. All numbers of propagules are expressed per 250 g of field soil. The results presented here are those from samplings done to assess the effect of {a) time of sampling and (b) grass control through weedicides.

Number of Pages

11

Keywords

Western Australia

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