| Title: |
Effect of glyphosate application to grass weeds on levels of Gaeumannomyces graminis var. tritici inoculum. |
| Authors: |
Bithell, S. L.1 sean.bithell@nt.gov.au; Butler, R. C.1; Mckay, A.2; Cromey, M. G.1 |
| Source: |
Plant Protection Quarterly. 2009, Vol. 24 Issue 4, p161-167. 7p. |
| Abstract: |
The cereal pathogen Gaeumannomyces graminis var. tritici (Ggt) that causes the disease take-all infects Elytrigia repens (couch) and a number of other grass weed species. Soil Ggt DNA levels 14 months after couch had been planted into a naturally Ggt infected site, in which Bromus willdenowii (prairie grass) was also present, indicated that the presence of couch maintained rather than increased Ggt levels. Following an early glyphosate application soil Ggt levels increased three and eight fold, one and two months respectively after application (86 days before wheat sowing) to plots with couch present. A later glyphosate application (38 days before wheat sowing) also resulted in rapid increases in Ggt inoculum levels in plots with couch and to a lesser extent in plots without couch. Results confi rm that couch is an important host of Ggt with more roots per wheat plant infected, more plants infected and a greater takeall severity in plots with couch present. Early or late glyphosate applications did not affect subsequent levels of take-all in wheat. Prairie grass seedlings were also identifi ed as a signifi cant Ggt inoculum source, but this effect was independent of glyphosate and couch treatments. Overall, increases in Ggt inoculum levels following glyphosate application are large and relatively rapid. Ggt inoculum associated with couch rhizomes is persistent. Finally, very early glyphosate applications will be required to allow time for the break down of couch rhizomes and decline in Ggt inoculum levels thus reducing the risk of take-all in subsequent wheat crops. [ABSTRACT FROM AUTHOR] |
| Database: |
Supplemental Index |