Page 210 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

foliar sprays significantly reduced the disease severity one year out of two. While foliar applications of
sodium carbonate peroxyhydrate and citric acid + lactic acid did not significantly influence ALS severity
for both years. Applications of hydrogen peroxide and hydrogen peroxide + peracetic acid also failed to
control the disease. This study shows the potential of copper-based pesticide and hot-steam treatment to
control ALS of strawberry. The effect of weather conditions on the development of the disease is also
presented.

[P12] EFFECT OF VOLATILE COMPOUNDS PRODUCED BY BROWN MUSTARD ON DIFFERENT
PLANT BENEFICIAL AND PHYTOPATHOGENIC MICROORGANISMS. Marwa Mejri, Maxime Delisle-
Houde, Thi Thuy An Nguyen, Martine Dorais, and Russell J. Tweddell. Département de phytologie,
Université Laval, Québec, QC G1V 0A6, Canada
Correspondence to: maxime.delisle-houde.1@ulaval.ca

Several studies showed the efficacy of biofumigation to control weeds, pests, and pathogens affecting
horticultural crops. Biofumigation is based on the release of toxic volatile compounds (isothiocyanates)
during the degradation of glucosinolates-rich plants of the Brassicaceae family. This study aimed to
evaluate, in vitro, the toxicity of volatile compounds produced by mashes of brown mustard [Brassica
juncea (L.) Czern.] (cv. Terminator) on the phytopathogenic fungi Rhizoctonia solani and Fusarium
oxysporum and the biocontrol agents Bacillus subtilis and Trichoderma harzianum. Petri dishes
containing PDA (fungi) or TSA (B. subtilis) inoculated with a mycelial disc (4 mm) or a bacterial
suspension (1 × 10 colony forming units mL ) were deposited in hermetic chambers (500 mL) containing
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different concentrations (0-120 mg mL ) of aqueous suspensions of brown mustard mash. The
fungal/bacterial growth was evaluated every 24 h during an exposition period of 72 h (22.5°C) to
determine the effect of volatile compounds produced by grinded brown mustard on the growth of the
tested microorganisms. Results obtained in this study show that volatiles generated by grinded brown
mustard (cv. Terminator) can inhibit the growth of plant pathogens as well as biocontrol agents.

[P13] ANTIFUNGAL ACTIVITY OF ESSENTIAL OILS FROM DIFFERENT NORDIC PLANT SPECIES
AGAINST BOTRYTIS CINEREA. Antoine Roy-Lemieux, Maxime Delisle-Houde, and Russell J. Tweddell.
Département de phytologie, Université Laval, Québec, QC G1V 0A6, Canada
Correspondence to: maxime.delisle-houde.1@ulaval.ca

Grey mold, caused by the fungus Botrytis cinerea Pers., affects a wide range of horticultural plant
species. Control of the disease relies mainly on the use of synthetic pesticides that cause numerous
negative effects in agriculture, the environment, and human health. The objective of the study was to
evaluate the antifungal and prophylactic properties of vapors of essential oils (EOs) from different Nordic
plant species including Labrador tea (Ledum groenlandicum), black spruce (Picea mariana), and Jack
pine (Pinus banksiana) against B. cinerea. The fungus was cultivated at 22.5°C on agar in a hermetic
chamber in presence of vapors produced by different quantities (0-100 μL) of EOs from Labrador tea,
black spruce, or Jack pine. After different incubation periods (0-96 hours), the mycelial growth was
measured. In order to evaluate the prophylactic effect of EOs, tomatoes (cv. Micro-Tom) previously
inoculated with a suspension of B. cinerea were incubated at 22.5°C in presence of vapors generated by
either of EOs. After an incubation period of 96 hours, the severity of grey mold was evaluated. The results
obtained highlight the antifungal activity of vapors of EOs from Labrador tea, black spruce, and Jack pine
against B. cinerea. Moreover, EOs allowed to significantly (p ≤ 0.05) reduce the severity of grey mold on
tomatoes. Future work will be undertaken to evaluate the potential use of these EOs in a commercial
context.

[P14] POTENTIAL OF FOREST PLANT EXTRACTS TO CONTROL ANGULAR LEAF SPOT OF
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CUCURBITS. Sabra Mimouni , Maxime Delisle-Houde , François Demers , Martin Filion , and Russell J.
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Tweddell . Département de phytologie, Université Laval, Québec, QC G1V 0A6, Canada; Club les
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productions Écolo-Max, Lévis, QC G7A 2N7, Canada; and Saint-Jean-sur-Richelieu Research and
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Development Center, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada
Correspondence to: maxime.delisle-houde.1@ulaval.ca

Angular leaf spot (Pseudomonas syringae) is a bacterial disease leading to significant yield losses in
cucurbit crops. Control of the disease relies mainly on the use of copper-based pesticides that are often
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