Page 301 - PC2019 Program & Proceedings

PLANT CANADA 2019

P175. Effect of host type on the virulence of Pyrenophora tritici-repentis (Ptr) in Canada
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1
3
4
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Wei, B. ; S. Strelkov ; R. Aboukhaddour ; T. Despins ; M. Fernandez
1 University of Alberta
AAFC
2
3 Agriculture and Agri-Food Canada, Lethbridge Research and Development Center
4 Agriculture and Agri-Food Canada, Swift Current Research and Development Centre

Onions are susceptible to Fusarium basal rot caused by the soilborne fungus Fusarium oxysporum f. sp.
cepae (FOC). Control of this pathogen is difficult with limited genetic resistance in onion. It is therefore
worthwhile to identify compounds that inhibit this fungus. We identified a strain of Brevibacillus fortis
that secreted antifungal compounds into the growth media. The spent media, diluted 1:1, inhibited
growth of FOC conidia after seven hours and killed 90% of conidia after 11 hours. The secreted
antifungal compounds retained much of their inhibitory activity after a one hour incubation at 75° C. The
spent media also inhibited growth of conidia from F. graminearum, F. proliferatum, F. verticillioides and
Galactomyces citri-aurantii. Analysis of the genome sequence indicated a number of antibiotics could be
produced by this bacteria isolate. Fractionation of spent media followed by reverse phase LC-MS
determined that fractions with antifungal activity contained a mixture of edeines A, B and F and no other
known antibiotics. These data indicate that this isolate could be utilized as a biological control organism
for onions. Alternatively, development of edeine as a Fusarium control product should be investigated
with more experiments.

Eric Johnson (eric.johnson2@ars.usda.gov)

P176. Emerging diseases of new hazelnut varieties grown in the Fraser Valley, British Columbia.
Drugmand, B.; V. Vasile; S. Sabaratnam
Ministry of Agriculture

Four to ten year-old orchards, planted with new hazelnut (Corylus avellana L.) varieties, were surveyed in
2017 and 2018 for overall plant-health and diseases caused by plant pathogens. The most common
symptoms were brown to dark-brown enlarging cankers with yellow-brown margins or sunken cankers
with splitting margins and ‘V-shaped’ internal discoloured tissues on branches of hazelnut varieties
‘Jefferson’, ‘Yamhill’, ‘Sacajawea’, ‘Theta’, ‘Eta’, and ‘Gamm’, resulted in ‘flagging’ and dieback of the
infected branches. Dark coloured pycnidia with pycniospores on the cankers and the pathogen isolated
from the tissues were confirmed as Phomopsis sp. by DNA analysis. On some tree-trunks, dark-brown to
black bleeding lesions and dark-brown discolouration of tissues beneath the lesions were observed.
Although the symptoms were suspected of Phytophthora spp. or Pseudomonas avellanae (Psallidas),
which causes bacterial canker, no pathogen was isolated from the symptomatic trunk tissues. In poorly
drained soils, root rot was commonly observed on 4 to 10 year-old trees. Affected trees displayed
weakened foliage, chlorosis and tree-decline. Phytophthora sp. “hungarica” was isolated from the
symptomatic roots and confirmed by DNA analysis. Besides Phytophthora, Cylindrocarpon and
Fusarium species were also isolated. Studies have been undertaken to identify the pathogens responsible
for the diseases, and to determine their pathogenicity and epidemiology for developing management
strategies to protect young hazelnut orchards in British Columbia.

Ben Drugmand (Ben.Drugmand@gov.bc.ca)

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