Page 303 - PC2019 Program & Proceedings

PLANT CANADA 2019

P179. Effect of Miravis Neo on Gibberella ear rot and related mycotoxins in corn grain
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Eli, K. ; D. Hooker ; V. Limay-Rios ; A. Schaafsma
1 University of Guelph
University of Guelph - Ridgetown Campus
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Fusarium graminearum Schwabe causes Gibberella ear rot in corn, resulting in yield loss, and poor grain
quality due its ability to produce mycotoxins, mainly deoxynivalenol (DON). Fungicides are important
for managing Fusarium spp. A proper fungicide resistance management plan has not been possible,
because all the recommended fungicides are from the same triazole class of chemistry. A new fungicide
Miravis Neo has been developed by Syngenta. It contains adepidyn belonging to the novel class of
®
carboxamides, making it possible to rotate classes of fungicides with different modes of action. The
objective of this study was to compare the effectiveness of Miravis Neo to standard fungicides for control
of Gibberella ear rot and reduction of mycotoxins in corn. Field experiments were conducted in misted
and inoculated plots in 2017 and 2018. Severity of GER was assessed visually and mycotoxins were
analyzed using HPLC-MS-MS. Under high disease pressure, Gibberella ear rot severity was reduced by
up to 60% compared to control. Fungicide treatments reduced DON concentration by 33 to 41%.
Zearalenone and total fumonisins were reduced by up to 90% and 67% respectively. Miravis Neo showed
similar levels of control to the standard fungicides, Proline and Caramba to reduce Gibberella ear rot and
mycotoxins, making it a good candidate to help manage resistance to fungicides by class rotation.

Katiani Eli (elik@uoguelph.ca)

P180. A rapid molecular assay to identify Plasmodiophora brassicae pathotypes from plant, soil and
water samples
Tso, H. ; L. Galindo-González ; H. Askarian ; M. Holtz ; S. Strelkov
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1 University of Alberta
2 Alberta Agriculture and Forestry
Clubroot of canola (Brassica napus), caused by the pathogen Plasmodiophora brassicae Wor., constitutes
a significant threat to the Canadian agricultural industry. The deployment of clubroot-resistant cultivars is
an effective management strategy; however, their widespread use has resulted in the emergence of new
pathotypes capable of overcoming resistance. Several host differential sets have been reported for
pathotype identification, including the differentials of Williams and the Canadian Clubroot Differential
(CCD) set. The current identification method is time-consuming, labour-intensive, and requires biosecure
facilities. The development of a rapid assay would facilitate pathotype identification and enable testing of
a much larger number of samples. We are focusing on single nucleotide polymorphisms found among
genomes of different pathotypes to generate highly specific ribonuclease H-dependent PCR (rhPCR)
assays. rhPCR amplification requires perfect binding of primers to the target, allowing for pathotype
differentiation with a single nucleotide difference. The blocked primers, containing a single
ribonucleotide residue, are activated via cleavage of the RNA base by the RNase H2 enzyme. To design
rhPCR primers, we obtained variant genome information for 45 full genome P. brassicae isolates, by
aligning them to the reference e3 P. brassicae genome. Analysis revealed that most polymorphisms
cluster CCD variants of pathotypes 5 and 6, grouping them separately from pathotypes 2 and 3.
Preliminary results suggest that rhPCR is promising as a rapid and efficient tool for pathotype detection.

Heather Tso (htso@ualberta.ca)

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