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Abstract Detail

Biological Control of diseases and weeds (CFBC)

Audy, Patrice [1], Boyetchko, Susan [2], Foran, Nicholas [3], Gravel, Valérie [3].

Can bacterial antagonists be used to complement synthetic fungicides as a control measure against potato late blight?

Late blight of potato (Solanum tuberosum L.), caused by Phytophthora infestans (Mont.) de Bary, is the world’s single most economically important food crop disease with crop losses and prevention measures estimated worldwide at more than $6.0 billion annually. Chemical fungicides are heavily used by potato producers to prevent and control the disease but public pressure has created a demand for environmentally friendly control products and a preference for pesticide-free foods are driving the exploration for biological control options. Moreover, incidence of new, more virulent P. infestans isolates and isolates becoming insensitive to existing synthetic fungicides has been challenging for producers to prevent late blight epidemics. The use of biological fungicides has thus been of considerable interest in complementing the arsenal of control measures against potato late blight. The objective of this study is to identify and develop biological alternatives for control of this economically important disease. A potato leaf bioassay was developed to study the ability of the bacteria to control the disease under environmental conditions optimum for disease development. From over 50 bacterial isolates, six leading candidates showed promising abilities to impede P. infestans growth (A1 and A2 mating-type isolates). For each bacterial strain evaluated, four treatments were tested: pathogen alone, whole bacterial culture + pathogen, bacterial filtrate + pathogen and autoclaved bacteria culture + pathogen. All treatments were compared to mock controls (minus pathogen, minus bacteria). Application of whole bacterial culture, and in some cases, bacterial filtrate alone, have resulted in significant reduction in disease severity. The presence of bacterial metabolites possessing antifungal compounds and induced resistance are implicated as possible modes of action. Further testing is required to determine optimum conditions for maximizing bacterial formulation.

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1 - Agriculture and Agrifood Canada, Soils and Crops Research and Development Centre, 2560 Hochelaga Blvd, Quebec city, QC, G1V 2J3, Canada
2 - Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
3 - McGill University, Plant Science, Raymond Building, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada

Phytophthora infestans
late blight

Presentation Type: Oral Paper:Papers for Topics
Session: 75
Location: Salon 2/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 5:00 PM
Number: 75006
Abstract ID:1142
Candidate for Awards:None

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