Phytopathology (2022) 112, 794-802

Maíra R. Duffeck, Ananda Y. Bandara, Dilooshi K. Weerasooriya, Alyssa A. Collins, Philip J. Jensen, Gretchen A. Kuldau, Emerson M. Del Ponte and Paul D. Esker (2022)
Fusarium head blight of small grains in Pennsylvania: Unravelling species diversity, toxin types, growth, and triazole sensitivity
Phytopathology 112 (4), 794-802
Abstract: Fusarium graminearum is the main causal species of Fusarium head blight (FHB) globally. Recent changes in the trichothecene (toxin) types in the North American FHB pathogens support the need for continued surveillance. In this study, 461 isolates were obtained from symptomatic spikes of wheat, spelt, barley, and rye crops during 2018 and 2019. These were all identified to species and toxin types using molecular-based approaches. An additional set of 77 F. graminearum isolates obtained from overwintering crop residues during winter 2012 were molecularly identified to toxin types. A subset of 31 F. graminearum isolates (15 15-acetyl-deoxynivalenol [15ADON] and 16 3-acetyl-deoxynivalenol [3ADON]) were assessed for mycelial growth, macroconidia, perithecia, and ascospore production, and sensitivity to two triazoles. Ninety percent of isolates obtained from the symptomatic spikes (n = 418) belonged to F. graminearum, with four other species found at a lower frequency (n = 39). The F. graminearum isolates from symptomatic spikes were mainly of the 15ADON (95%), followed by 3ADON (4%), nivalenol (0.7%), and NX-2 (0.3%) toxin types. All F. graminearum isolates obtained from overwintering residue were of the 15ADON type. The toxin types could not be differentiated based on the multivariate analysis of growth and reproduction traits. All isolates were sensitive to tebuconazole and metconazole fungicides in vitro. This study confirms the dominance of F. graminearum and suggests ecological and environmental factors, to be further identified, that lead to similar composition of toxin types in the northern United States. Our results may be useful to assess the sustainability of FHB management practices and provide a baseline for future FHB surveys.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Gretchen A. Kuldau, Paul D. Esker

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
general biology - morphology - evolution

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Fusarium graminearum	Barley (Hordeum vulgare)	U.S.A. (NE)
	Fusarium graminearum	Rye (Secale cereale)	U.S.A. (NE)
	Fusarium graminearum	Wheat (Triticum)	U.S.A. (NE)