Competition and reproduction ability of volunteer Clearfield oil seed rape and its control Miroslav Jursík Michaela Kolářová Veronika Fendrychová Luděk Procházka
Adventages of Clearfield technology in oil seed rape high selectivity of imidazolinone herbicides to CL hybrids compared to lower selelectivity of some conventional herbicides wide weed spectrum including problematic weeds (Brassica and Geranium family) and cereals volunteer wider application interval compared to conventional herbicides higher tolerance to residues of ALS inhibitors in soil chloracetamides Imidazolinone herbicides ethametsulfuron Auxine herbicides Injury caused by propoxycarbazone residues Injury caused by clomazone
Risks of Clearfield technology Increasing use of ALS inhibitors shift of weed spectrum (Viola spp.) risk of herbicide resistance development (Brassica spp.) Problems with control of CL oil seed rape volunteer in subsequent crops: cereals sugar beet soyabean etc.
Aims of present work Quantify of competition and reproduction ability of volunteer oil seed rape in spring barley and winter wheat Describe of differences in sensitivity between Clearfield and conventional oil seed rape volunteer to different herbicides used in cereals Suggest technology for Clearfield oil seed rape volunteer control in cereals
Methodology Three small-plot field experiments in spring barley and winter wheat was caried out in growing seasons (2014/15, 2015/16 and 2016/17) F2 generation of Conventional and Clearfield hybrids was separately sown (60 kg/ha) shortly before wheat and barley (September, resp. March). Assesments: Herbicide efficacy Biomass production of oil seed rape Seed production of oil seed rape Yield of cereals
Tested herbicides: autumn application diflufenican metribuzin Cougar Forte Trinity Legato Plus Bizon Bacara Trio
Tested herbicides: autumn application flumioxazin chlorsulfuron Sumimax Glean Efficacy on conventional volunteer OSR only
Tested herbicides: spring application 2,4-D tritosulfuron + florasulam Most effective spring herbicide Husar Active Husar Active Plus Mustang Mustang Forte Sekator Plus Most effective ALS inhibitor Biathlon
Tested herbicides: spring application ALS inhibitors with low efficacy on CL OSR volunteer: amidosulfuron (Sekator) also rather low efficacy on conventional OSR iodosulfuron (Husar, Sekator) tribenuron (Biplay) metsulfuron (Biplay) thiencarbazone (Husar TCM) Auxine herbicides with low efficacy on OSR volunteer: fluroxypyr (Starane)
Experiment in winter wheat in 2014/15 Clearfield oil seed rape volunteer iodosulfuron + 2,4-D + thiencarbazone iodosulfuron + 2,4-D florasulam + 2,4-D florasulam + 2,4-D + aminopyralid amidosulfuron + iodosulfuron + 2,4-D amidosulfuron + iodosulfuron flumixofazin diflufenican + isoproturon pendimethalin + diflufenican + chlorotoluron pendimethalin + isoproturon diflufenican + flufenacet + metribuzin diflufenican + flufenacet untreated Conventional oil seed rape volunteer
Experiment in winter wheat in 2015/16 Clearfield oil seed rape volunteer tritosulfuron + florasulam iodosulfuron + 2,4-D + thiencarbazone iodosulfuron + 2,4-D florasulam + 2,4-D florasulam + 2,4-D + aminopyralid amidosulfuron + iodosulfuron + 2,4-D amidosulfuron + iodosulfuron chlorsulfuron flumixofazin diflufenican + isoproturon diflufenican + florasulam + penoxsulam pendimethalin + diflufenican + chlorotoluron diflufenican + flufenacet + metribuzin diflufenican + flufenacet untreated Conventional oil seed rape volunteer
Difference between autumn and spring treatment (conventional OSR volunter) Spring application of Sekator OD (amidosulfuron + iodosulfuron) Autumn application of Glean 75 WG (chlorsulfuron) Grain yield on plots treated at spring was about 1 t/ha lower compared to autumn treatments (p=0.0006)
Experiment in winter wheat in 2016/17 Volunteer OSR completely frozen during the winter
Experiments in spring barley Conventional OSR volunteer CL OSR voluneer tritosulfuron + florasulam tribenuron + metsulfuron + fluroxypyr amidosulfuron + iodosulfuron amidosulfuron + iodosulfuron + 2,4-D florasulam +2,4-D 0 10 20 30 40 50 60 70 80 90 100 Efficacy (%)
Seed production of volunteer OSR Winter wheat Without control: 20,000 40,000 seed/m 2 Efficient herbicide control: 0 500 seed/m 2 Spring barley Without control: 0 500 seed/m 2 Efficient herbicide control: 0 seed/m 2
Positive effects of agronomical and weather factors Winter wheat Late sowing (second half of October) Long freezing during winter effectively controlled OSR volunteer (often in highland) Excellent soil preparation and/or glyphosate treatment of stubble (elimination of old plants of OSR volunteer - regeneration)
Positive effects of agronomical and weather factors Spring barley Dry and hot spring reduced emergency of OSR volunteer and increased infestation by insects
Conclusions Competition and reproductive abilities of oil seed rape (OSR) volunteer are higher in winter cereals compared to spring cereals (suitable bionomic condition and lower pest infestation) Autumn OSR volunteer control showed better efficacy than spring control Spring treatment in winter wheat is possible (2,4-D) but OSR volunteer may cause yield loss, especially in dry condition (competition about water) All autumn applied herbicides containing diflufenican, resp. flumioxazin showed sufficient efficacy on Clearfield (CL) OSR volunteer In case of insufficient soil preparation or high infestation by CL OSR volunteer, application of metribuzin is needed (most effective autumn herbicide)
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