In the field experiment, the efficacy of the active substances thiencarbazone-methyl, foramsulfuron, mesotrione, S-metolachlor, dimethenamide-P and nicosulfuron for the control of panicoid grass weeds was tested. Herbicides were applied to the populations of plants that were in an experimental maize field established by sowing seeds collected in various regions of Slovenia (Mursko polje, Dravsko and Ptujsko polje, Krško polje, Savinska and Vipava valleys) and then planted in the mentioned field. We harvested grass seeds in the fields where farmers were unsuccessful in their suppression. We studied the following species: Panicum dichotomiflorum, P. capillare, P. milliaceum, Setaria faberi, S. glauca, S. viridis, Echinochloa cruss-galii and Sorghum halepense. In several populations, a significant reduction in the effectiveness of herbicides was found. Efficacy fell to a level of 60 to 80%, but the resistance of the studied grasses to the herbicides tested cannot be proven. There are signs of segregation of tolerant populations in several regions of Slovenia. Since soil seed banks of the studied weeds are big, despite the mediumhigh efficacy of herbicides, massive losses of corn yields are encountered, especially in arid conditions.
COBISS.SI-ID: COBISS.SI-ID 454
Research on pesticide resistance of Two-spotted spider mite, Tetranychus urticae Koch, to chemical acaricides in Slovenian hop gardens is presented in the paper.
COBISS.SI-ID: COBISS.SI-ID 751
In a field experiment, the efficacy of herbicides for the control of the common windgrass in wheat crop based on combinations of active substances such as thiencarbazone-methyl, iodosulfuron, mesosulfuron, pinoxaden, piroxulam, duflufenican, chlorotoluron and pendimethalin was tested. The herbicides were applied to the populations of windgrass plants that were established by planting seeds which had been collected in 20 locations in north-eastern and eastern Slovenia. We harvested seeds in fields, where farmers were not successful in suppressing windgrass, and where over 100 plants per m2 were developed. The efficacy of herbicides ranged from 50 to 95%. In most of the tested windgrass populations, the efficacy of most of the tested herbicides ranged between 75 and 90%. The results of the study did not confirm the resistance of windgrass to herbicides. A somewhat reduced efficiency was found in our trial which can in case of high windgrass density, mistakes in the timing of application of herbicide and unsuitable application techniques,cause a significant increase in population of windgrass (often above 150 plants per m2). Highly infested fields are often a result of use of non-effective herbicides that are not registered for windgrass control and not due to resistance to herbicides that have a declared efficacy for the control of this weed. The available, registered herbicides enable a good level of control (90-95%) until the amount windgrass seed in the soil is not too large, and assuming that we apply the herbicide correctly.
COBISS.SI-ID: COBISS.SI-ID 298
Different weed control strategies are presented in the paper.
COBISS.SI-ID: COBISS.SI-ID 572