Late blight risk on potatoes : assess it with Sencrop

Weather parameters are at the origin of the development of certain parasites and fungi on crops. Having a weather station to know these parameters is a great help to prevent these risks.

In order to help growers manage their cultivation itineraries, Sencrop has developed an indicator for potato blight based on the Hutton criterion. The objective: to know more precisely the risk of development of the disease on its plots.

Late blight risk calculated using the Hutton criterion

The presence of late blight is favoured by a humid climate

Late blight is the most common disease of potatoes in England. Its development is favoured by a humid and temperate climate and an often late harvest, in humid conditions. This fungal disease of potatoes is responsible for significant damage in English fields. The tuber is produced on about 120,000 hectares in England by more than 1600 growers. The disease costs £50 million in chemical treatments alone.

The Hutton criterion measures the risk of Phytophthora infestans development

To prevent the disease, research groups have studied its development. It is the result of a fungal parasite called “Phytophthora infestans” The latter develops according to specific meteorological variables. One of the most common risk criteria used by the scientific community to predict the risk of its development is the “Hutton criterion”

It is calculated by taking into account the combination of 2 parameters on 2 consecutive days:

• A temperature of at least 10°C.
• A relative humidity of at least 90%.

A model integrated in the Sencrop application

A partner in the estimation of the “potatoe blight” risk

This risk criterion is now taken into account in the Sencrop application in England exclusively.
Access is via the application, under the heading “Agronomy”. A table shows the risk of apple blight in the form of icons representing the days of the week.

In concrete terms, the weather station measures the parameters temperature and air humidity. As soon as the figures fall within Hutton’s criteria, the application indicates that the variables have moved into the risk zone by means of a colour code that changes from green to red.

Its ultimate purpose is to warn of the risk of potato blight development. If this is an early indicator to secure the decision making, it is always advisable to check the actual situation on the plots afterwards.

An indicator to investigate the possibility of chemical intervention

Once this observation has been made by the producer, it is recommended to turn to his usual technical advisor. The Hutton criterion do not lead necessarily to treatment. Rather, it should be interpreted as a warning tool. If chemical protection is required, it will be decided on the basis of visual observations and technical data that can be gathered from various institutes and cooperatives. In any case, the functionality can help :

• With a more reasoned use of phytosanitary products.
• To think more calmly about the right moment to treat.

It allows the potato grower to take base on precise and scientifically verified indications before consulting an technical advisor.

To go further: connecting the application to a DST (Decision Support Tool)

It is also possible to connect the Sencrop application to certain Decision Support Tools (DST). Some of them are specialised in forecasting the risk of late blight on potatoes. By activating them, the grower will be able to access precise advice on the positioning of treatments.

A “late blight” functionality that will be developed further

The “late blight risk” functionality is one of the first models integrated into the tool, along with cercosporiose in beets. It is available to customers who subscribe to the “Plan Plus” of the Sencrop app. In the current version, the user of the app has to consult the app to be alerted to potential risks. In the near future, it will be possible to receive an automatic notification when the risks are confirmed.

However, the farmer can already set certain alerts manually via the existing tool.

The aim of developing this service is to support producers in their reflexion for technical itinerary construction, in accordance to Sencrop’s will to give democratized access to data to facilitate better decision making to all farmers.

Sources :
https://ahdb.org.uk/potato/planted-area
https://ahdb.org.uk/late-blight