When vines meet cutting-edge technology

Could the performance of sprayers used to spread phytosanitary products over vines be tested ? "When we implemented in-field tests, we were faced with various problems: we needed to find appropriate plots of land for measurements, mobilise farmers, have good meteorological conditions etc. It wasn’t easy", explains Bernadette Ruelle, Deputy Director of the Information, Technology and Environmental Analysis for Agricultural Processes (ITAP) Research Unit at the Irstea Montpellier Centre. To overcome these difficulties, researches at the French Institute for Vine and Wine and Irstea had an ingenious idea : to develop an artificial vine ! Its name : EvaSprayViti.

Decoding an artificial vine

"We designed this device so that it would "mimic" the rows of vines and leaves as closely as possible", continues the researcher. The test bench is therefore made up of 4 parallel nets, each measuring 10 metres in length and copying the layout of vine rows. Sensors take the place of leaves and are designed to move like leaves when blown by wind. They are the heart of this innovative measuring system. Depending on the number of sensors used, researchers can test the vine in several vegetative states that correspond to various moments which each require different products and at different doses. Thus 120 “leaves” are used to represent early vegetation, 440 for mid-vegetation and 840 for full vegetation. In 2012, researchers from IFV and Irstea compared measurements taken from a natural vine and from the artificial vine and found the results to be very comparable.

"With this device, we can measure the amount of deposit left on the leaves and get an overview of losses into the soil and air", explains Bernadette Ruelle. These losses are one of the negative aspects of spraying phytosanitary products. Several studies have looked at the effects: a significant amount of sprayed product, sometimes more than half, does not reach the plant as the spray is dispersed into the atmosphere or falls back to the ground. Why ? Poor quality spraying material as well as incorrect settings or a mismatch between the treatment process and the vegetation being treated. Spacing between rows, foliage height and the surface being treated can also vary between two sites as well as from one season to another.

According to the specialist, "with the artificial vine, we can play with all these parameters. For example, vines in Burgundy are spaced at around one metre intervals, while those in Languedoc are at 2.5 metre intervals. Technically, it is possible to simulate these details and, by adjusting the settings, study the spraying performance of various materials". At the Irstea facility where EvaSprayViti is set up, scientists can also easily set up their experiments to run at different times to measure the differences found according to changes in weather conditions (temperature, moisture content, wind speed, etc.).

Ecophyto 2018 on the horizon

Among the tests already completed by this test bench is the comparison between an innovative sprayer with recovery panels and fan and air injection nozzles and an older pneumatic arch sprayer that remains common among French vineyards. The verdict from the artificial vine was that the former directed 85 % of the phytosanitary product onto the leaves while the latter managed only 55%. "Although the Ecophyto plan requires a reduction of up to 50 % in pesticide use in France, by 2018 if possible, the resources available on the market can still be improved. This device will allow us to repeat many tests, which will help us to determine which sprayer characteristics provide the best performance", notes Bernadette Ruelle.

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