In South-East Hungary the weather conditions generally are dry in spring so the efficacy of preemergence weed control methods is not sufficient. Most preemergence herbicide requires 10-20 mm of precipitation within 2 weeks after application to increase their effectiveness. Experiments were conducted in Hódmezővásárhely, southern part of the Great Hungarian Plain in 2005 and 2006 to study different postemergence weed control technologies in small plots in maize. The characteristic weeds on the experimental plots were the Sorghum halepense, Datura stramonium, Chenopodium album, C. hybridum, and Amaranthus retroflexus. The efficacy of the herbicide combinations against dicotyledonous weeds was very similar in the two years. Herbicide treatments contain nicosulfuron combined dicamba + bentazone or mesotrione or tritosulfuron + dicamba and rimsulfuron + dicamba combination controlled dicot weeds with a very good result. The efficacy of foramsulfuron + isoxadifen-ethyl against Chenopodim species was moderate, while florasulam + 2,4 D killed these weeds with a low level of efficacy. In 2005 - when the weather was hot and rainy 2 weeks before and after the treatment - we observed an excellent weed control result against Sorghum halepense. The efficacy of the herbicides was a bit poorer in 2006 because of the cold and too rainy weather. None of the examined herbicide combinations injured maize. At harvesting yield was measured and the data was analysed by variance analysis. Significant yield loss of maize was observed caused by the high weed infestation on those plots where the herbicide effect against weeds was low and on the untreated plots.

maize; postemergence weed control; adjuvant; Sorghum halepense; dicot weeds

Presentation: oral