Bladsvampe – midler og doseringer / Leaf diseases – products and doses

Conclusion

In three field trials with sugar beet varieties Lombok and Fairway, two applications with 1.0, 0.5 or 0.25 liters pr. ha of Opera or Maredo 125 SC have been tested. Comet Pro is tested with 0.3 and 0.6 liters pr. ha. A tank mixture of 0,25 liters Opera with either 5,0 Thiopron or 2,0 liters Tridex DG have been tested. Moreover, Amistar Gold is tested with 1,0 liters following 0,6 liters Comet Pro, and, moreover, 2 x 0,5 liters Amistar Gold is tested. Rust and Ramularia have been the dominant leaf diseases in 2017. Opera indicates a higher efficacy on rust and Ramularia compared to the efficacy achieved by Maredo. Amistar Gold indicates an efficiency comparable to Opera. Addition of Thiopron and tank mixture with Tridex DG to Opera show no or minor efficacy on rust and Ramularia. Two treatments with 0.5 liters Amistar Gold have achieved effect against rust and Ramularia almost on level with twice 0.5 liters of Opera. The trials in 2017 show a yield increase of between 0.88 to 1.94 t sugar pr. ha which is between 6 and 13 pct. yield increase. Highest net economy is obtained with two applications of 0.50 liters Opera per ha. Average from trials conducted 2009 to 2017 show that the highest net economy is achieved with two treatments of 0.25-0.50 liters Opera pr. ha, providing 9-10 pct. yield increase which result in about 1.300 DKK per ha in net economy. Two treatments with 0.25-0.50 liters Maredo 125 SC per ha have resulted in 6-8 pct. in yield increase and show lower net economy compared to Opera. The average of trials 2015-2017 shows that the addition of Thiopron to 0.25 liters of Opera per. ha has yielded higher net economy than Opera alone, which is mainly due to effect on severe mildew attacks in 2016