Survey of Claviceps purpurea and Fusarium Toxins in Spring Wheat and Fungicide Efficacy on Ergot Sclerotia, Alkaloid Content, and Saprophytic Fusarium Associated Toxins
Abstract
Fusarium head blight (FHB) and ergot of the claviceps purpurea (Fr.) Tul. have adverse effects on grain quality and human and animal health. Each year, Hard Red Spring (HRS) wheat samples are collected at harvest to survey the end use quality. HRS-wheat survey samples (n= 207) were obtained from four growing states (ND, SD, MN, and MT) during 2019 and 2020. Grading and non-grading factors and the presence of Deoxynivalenol (DON) and ergot alkaloids (EAs) were determined, naturally occurring mycotoxins produced by Fusarium species and C. purpurea, respectively.
Chromatography-Mass Spectrometry (GC-MS) was utilized for DON content and Reveal Q+Max test for total EAs. The mean DON contents during the 2019 and 2020 growing seasons were 1.5 ppm and 0.6 ppm, respectively. The mean for total EAs contents in 2019 and 2020 were 81.5 ppb and 180.5 ppb, respectively. Both toxins showed location had significant (P≤0.05) effect on variations within one individual year. Deoxynivalenol and EAs shared positive and significant correlations with total defects (0.257, P<0.001) and (0.162, P<0.05), respectively.
In the field experiment, four fungicides (Sphaerex, Miravis Ace, Quilt, and Priaxor) were applied on a confidential HRS wheat cytoplasmic male sterile (CMS-HRS wheat) line. After separating the ergot sclerotia samples from other contents, they were evaluated for naturally occurring saprophytic Fusarium toxins and EAs. The mean value for DON content in Miravis Ace (0.07 ppm) sample was significantly (P≤0.05) less than the mean value for the non-treated control and Priaxor samples (0.24 and 0.21ppm, respectively). Ergot body weight was significantly (P≤0.05) higher for the non-treated control compared to other treatments. Among fungicides, ergot body weight was significantly lower in Miravis Ace samples (39.57 g) compared to Quilt (55.83 g), Priaxor (55.04 g), and Sphaerex (54.82 g) treated samples. Total EAs in Priaxor (244,840 ppb) samples was significantly (P≤0.05) less than the mean values found in Sphaerex and Quilt samples (359,485 ppb and 352,375 ppb, respectively). Priaxor could be a potential fungicide to control ergot body weight and total EAs production. Future studies are needed to test more fungicides’ effectiveness to reduce ergot body and total EAs production.