Field trials were carried out with the wheat cultivar Enola in the period 2013-2014, using the same method in two different sites – the Experimental fields of the Agricultural University – Plovdiv and in the village of Krumovo near Plovdiv.
The fields were infested by the following important broad-leaved weeds: black-bindweed (Falopia convolvulus L.); common poppy (Papaver rhoeas L.); charlock mustard (Sinapis arvensis L.); flixweed (Descurainia sophia L.); cleavers (Galium aparine L.); field larkspur (Delfinium consolida L.); creeping thistle (Cirsium arvense L.); corncockle (Agrostemma githago L.) and the grassy weed wild oats (Avena fatua L.).
The efficacy, selectivity and tank-mixability of the tested herbicides and their combinations were studied: ready mixture Ergon WG (68 g/kg metsulfuron-methyl + 682 g/kg thifensulfuron-methyl) at the rates of 6, 7, 8, 9 and 18 g/da, ready mixture Granstar super (250 g/kg tribenuron-methyl + 250 g/kg thifensulfuronmethyl) – 4 g/da, mixture of Ergon WG – 7 g/da + Puma Super 7,5 EW (69 g/l fenoxaprop-P-ethyl) – 100 ml/ da, mixture Ergon WG – 7 g/da + Topic 080 EC (80 g/l clodinafop) – 50 ml/da and mixture Ergon WG – 7 g/da + Axial 050 EC (50 g/l pinoxaden) – 90 ml/da.
All the products were tested at the rates registered in Bulgaria and they were compared to untreated control areas. The treatments were carried out during the tillering stage untill 2nd node of the crop (ВВСН 29- 31). All the trials were conducted on plots of 25 m² in 4 replicates and a demonstration trial on 20 da was implemented. The trials were carried out based on EPPO Standards of the EU. Climatic conditions in 2013 were normal, but in 2014 it was unusually rainy.
Ergon WG herbicide applied at the rate of 70 g/ha, successfully controlled most of the broad-leaved weed species on the three sites. The efficacy of Ergon WG, against Galium aparine (L.) and Cirsium arvense (L.) was excellent only when applying the higher rates of 8 and 9 g/da. Mixtures of the products Ergon WG + Puma Super 7,5 EW; Ergon WG + Topic 080 EC and Ergon WG + Axial 050 EC showed excellent tank-mixability, without any antagonism in the efficacy against both broad-leaved and grassy weed species.
Ergon WG showed very high selectivity for the crop even when used at the double rate of 18 g/da. External symptoms of phytotoxicity were not observed in the crop after treatment with any of the herbicides and their mixtures.