Effect of fungicides on Fusarium infection and production of deoxynivalenol in spring cereals

Field trials in spring wheat and spring barley were carried out over two years in Dotnuva, in the center of Lithuania. Different fungicidal spray programs were used in 20042005 to determine their efficacy in controlling Fusarium infection and toxin deoxynivalenol (DON) accumulation in the grain. Azoxystrobin alone, and in a tank mixture with tebucanozole, a commercial mixture of prothioconazole and tebuconazole were used in spring barley. Epoxiconazole commercial mixture with pyraclostrobin and fenpropimorph, and tebuconazole alone were used in spring wheat. Fungicides were used at booting and heading or flowering stages. Naturally contaminated freshly harvested grain was analyzed. The Fusarium fungi infection level in grain was very high in both experimental years: in 2004 the level was 38.5– 50.0%, and in 2005,45.0–70.8%. A lower percent of infected grains was found in spring wheat compared with spring barley. During 2004 there was identified 16.8–28.3% infection level; in 2005, 28.3–49.3%. Only in 2005 did fungicide treatments at heading or flowering slightly reduce the Fusarium infection. The level of mycotoxin DON detected in the grain samples was generally low and varied from 21 to 168 μg kg.