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Blight alert, a simple decision support system for Prince Edward Island potato farmers

Project Code: PRR07-650

Project Lead

Rachael Cheverie - Agriculture and Agri-Food Canada


Accelerate adoption of an effective late blight prediction system to assist PEI potato growers with the implementation of reduced risk management strategies on their farms

Summary of Results

Prince Edward Island (PEI) has ideal growing conditions for the devastating Phytophthora infestans or Late Blight fungus with the high humidity in the form of dew, rain or fog, moderate day temperatures and cool night temperatures. As a result, the fungus can be wind swept from field to field very quickly. The disease spreads rapidly if adequate control measures are not adopted by all farmers in the region. Potato growing in PEI is very intensive with fields situated close to each other. If one grower does not protect his fields adequately, his infected fields will increase the disease pressure in the whole region. This means the growers with nearby fields have to take more controlling measurements to keep their fields free from infections.

The current way of controlling Late Blight costs the PEI economy many dollars in chemicals and crop losses. PEI growers base their control strategy on a calendar based schedule (a weekly spray). Changing from this strategy to an infection event driven strategy has the potential to reduce the use of chemicals drastically.

The objective of this project was to accelerate the adoption of an effective Late Blight prediction system to assists PEI potato growers with the implementation of reduced risk management strategies on their farm.

The prediction system, PLANT-Plus system, is a model developed in the Netherlands by the company Dacom. This model calculates disease infection events of the Late Blight fungus. The model combines input of recorded weather data like temperature, wind speed, rainfall and humidity with the local weather forecast and scientific knowledge about the life cycle of the fungus. The model provides a personal spraying advice for a grower through the combination of the infection events in the area and the degree of protection of the crop by chemicals and to new growth of leaves.

In order to get the information to every potato grower in PEI, the project partners developed a simple, innovative way to inform them about the daily local situation concerning Late Blight. Oncoming Late Blight infection events, the weather forecast for the next 10 days and the expected spraying conditions has been presented daily to 120 potato growers by e-mail and faxes from June 25 to October 1. To stimulate the implementation of the advice, the e-mails have been supported by extra text messages on the cell phone to a selected number of growers.

Atlantic AgriTech Inc. set up an independent trial to check the accuracy of the predicted infection events. A trial field was set up on which the advises of the model were put into practice. This field was compared with a field that was sprayed according to the practice of the farmer. At the end of the season, the reduction of treatments, the costs and level of infected plants were determined. Results indicated that overall, the Plant-Plus model was just as effective as controlling late blight as the conventional 7-day spray schedule. There was considerable late blight in the area and neither treatment had any during the season.

At the end of the season, a grower survey took place to ask the growers about their experiences with the information they received throughout the season. Focus was laid on the amount of chemical applications that was applied and if there was a difference between the standard practice, the farmers that received the faxes/e-mail, and the farmers that additionally received a text message during critical periods.

Results from the grower survey indicate that the Plant-Plus model may be difficult to follow for a number of reasons. Many growers feel that given today's acreage, sprayer capacity and unpredictable weather conditions throughout the summer on PEI, it would be very difficult to completely follow the recommendations of any blight forecast system including Dacom. However, that being said, 82% of producers receiving the faxes said they would be supportive of the PEI Department of Agriculture continuing to provide this service but only 18% said they would be willing to pay a fee to access this information.

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