Top Crop Manager

News Canola Diseases Insect Pests
Speeding up aster yellows identification


March 10, 2020
By Top Crop Manager

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Scientists in Canada have developed a novel method that enables rapid identification of aster yellows, facilitating faster response to combat the condition.

Transmitted by insects, especially the aster leafhopper, aster yellows outbreaks can cause severe production losses in huge numbers of crops, including many vegetables and cereals; one being canola. Depending on the environmental conditions and number of infected leafhopper insects, aster yellows can be transmitted to canola in less than 24 hours. The leafhoppers can then continue spreading the disease for the rest of their lives, which can be several weeks.

Canola is a billion-dollar industry on the Prairies, so the contraction and spread of aster yellows requires careful monitoring and control. Until now, detection strategies have taken several days, allowing rapid transmission of the disease.

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However, scientists from Agriculture and Agri-Food Canada (AAFC) in Saskatoon and the University of Saskatchewan have developed a rapid, simple laboratory and field-adaptable DNA extraction method that allows them to identify both plant pathogen and insect vector using molecular barcoding and gene sequencing. This novel method enables pathogen presence to be identified in under one hour from the time of insect collection.

Karolina Pusz-Bochenska, PhD candidate at the University of Saskatchewan and lead author of the study results published in Plant Health Progress [journal], writes, “Using this methodology, we were able to go from DNA extraction to pathogen detection in less than one hour. This rapid technique allows for same-day management decisions, essential to preventing the spread of insect-transmitted pathogens.”

To achieve this quick turnaround, Pusz-Bochenska and colleagues used DNA lysis paper to extract pathogen DNA, which they combined with the rapid-detection potential of the sensitive and field-adaptable loop-mediated isothermal amplification (LAMP) assay. According to Pusz-Bochenska, this combination was novel to the industry and has facilitated a huge change in the ability to manage the disease.

“When the aster leafhoppers migrate into Canada in spring, they bring aster yellows phytoplasmas that can cause devastating damage to canola crops. We need a rapid test to determine if these migrant leafhoppers are a threat or not. A rapid analysis allows us to estimate the infectivity of the population and forecast the risk to the crops, allowing the growers to make management decisions if the leafhoppers have arrived in their fields.”