This growing season, the Ontario Potato Board asked me to evaluate an innovative spore trapping technology to take late blight management to the next level. Spore traps should detect the presence of late blight spores in the air before infection takes place and before symptoms are visible in fields.
Knowing that late blight spores are present will help potato growers to better time sprays and to include fungicides specific to late blight which are more effective than protectant fungicides. Wind can spread spores up to a hundred kilometers; thus late blight spores are likely present in other areas of the province.
We installed spore traps in potato fields in the Alliston and Shelburne areas. The filters that trap the spores were replaced twice a week and sent to a laboratory for analysis. Polymerase Chain Reaction (PCR) based tests were used to identify the presence of late blight. This test is very reliable and specific; the risk of false positives is negligible.
To validate the performance and effectiveness of the spore traps, the fields were monitored twice a week; drone technology was used once a week.
All the PCR tests in June gave negative results; no late blight spores were found in the traps. However, during the week of July 7, late blight spores were trapped in both areas, Alliston and Shelburne. Field scouting and drone flights indicated that the fieldsm were healthy and well protected with fungicide applications. These preliminary results indicated that spore traps are invaluable tools to predict the development of potato late blight. Weather conditions -- wet and cool -- are also important factors that influence the development of this disease.
Emails were sent to the organizations of Ontario potato growers and tomato growers that late blight spores were in the Alliston and Shelburne areas. The project ended the last week of August. Studies will continue in 2017.
This project is funded in part through Growing Forward 2(GF2), a federal-provincial-territorial initiative. The Agricultural Adaptation Council assists in the delivery of GF2 in Ontario.