Investigations on herbicide resistance in European silky bent grass (Apera spica-venti) populations
- Publication Type
- Journal contribution
- Authors
- Dario Massa and Roland Gerhards
- Year of publication
- 2011
- Published in
- Journal of Plant Diseases and Protection
- Band/Volume
- 118/1
- ISBN / ISSN / eISSN
- 1861-3829
- Page (from - to)
- 31-39
In this study, the results of two-year investigations on herbicide resistance in silky bent grass (Apera spica-venti) populations are presented. Whole-plant bioassays were conducted with different herbicides on over 250 A. spica-venti populations from Central and Eastern European agricultural fields where herbicides failed to achieve satisfactory control. Results showed that over 60% of the suspected populations could be rated resistant to acetolactate synthase (ALS)-inhibitors, resistance to acetyl-CoA (ACCase)-inhibitors could be observed in only a few cases and no resistance to photosystem II (PSII)-inhibitors was detected. Dose-response experiments conducted in the greenhouse on resistant populations with the herbicides flupyrsulfuron-methyl, mesosulfuron+iodosulfuron and fenoxaprop-P-ethyl revealed resistance factors at ED50and ED90ranging respectively from 11 to 142, from 2 to 15 and from 4 to 6, thus confirming the prevalence of resistance to ALS-inhibitors in A. spica-venti . In greenhouse experiments, percentage canopy cover after herbicide treatment was determined in susceptible and resistant populations for the herbicides sulfosulfuron and fenoxaprop-P-ethyl by using digital image analysis. A significant effect of herbicide dose on canopy cover was observed in susceptible plants 7 and 15 days after treatment with sulfosulfuron, as well as in all populations when treated with fenoxaprop-P-ethyl. Canopy cover correlated significantly with plant dry weight in all populations, thus indicating that digital image analysis may represent a valid alternative approach to whole-plant bioassays and dose-response analysis for estimating biomass reduction after herbicide treatment. This work provides weed scientists with reliable tools for the verification of herbicide resistance in suspected weed populations.