Effect of three systemic fungicides on deoxynivalenol (vomitoxin) production by Fusarium graminearum in wheat

The effect of triadimefon, propiconazole and thiabendazole fungicides on the growth of Fusarium graminearum and the production of deoxynivalenol in wheat was investigated in a field trial. The heads of wheat plants were infected with F. graminearum spores (1 × 10 5 conidia mL −1 , approximately 62.5 mL m −2 ) 2 d following anthesis. Triadimefon (Bayleton 1.8 E.C), propiconazole (Tilt 3.6 E.C) and thiabendazole (Mertect 340-F) were sprayed at the dosages of 60, 120, and 360 g a.i. ha −1 , respectively. Treatments of wheat plants with the fungicides were conducted at three time schedules: (1) one application at 2 d before inoculation, (2) one application at 2 d after inoculation, and (3) two applications at 2 d before and 2 d after the inoculation of wheat plants with F. graminearum. Treatments with triadimefon and propiconazole fungicides resulted in 39–61% and 34–79% decreases in F. graminearum infection and deoxynivalenol levels, respectively. Although treatment with thiabendazole resulted in the maximum reduction (83%) in deoxynivalenol level, it had no significant effect on F. graminearum infection.Key words: Fusarium graminearum, deoxynivalenol, vomitoxin, fungicides, triadimefon, thiabendazole, propiconazole