Detecting copper-based fungicides in vineyards by means of hyperspectral imagery

Fungal diseases affecting vineyards are commonly controlled using copper-based fungicides. Inaccurate application of these products usually leads to accumulations of copper in the soil. The use of spectral images in vineyards is a tool that can help in the correct application of fungicides to improve their efficiency and effectiveness. To do that, a solution is required to identify the copper deposited on the vine leaf. To bridge this gap, the present work compares images obtained with a hyperspectral camera (Pika L, Resonon) of vineyard leaves (Vitis vinifera L.) cv. Tempranillo treated with two copper-based products, Cuprantol duo (Syngenta, CH) and Cuprocol (Syngenta, CH). Treated leaves with both products and the corresponding blanks made with distilled water were compared. Most of the differences between treatments and products are found in the near-infrared region (700–740 nm), the green region (550 nm) and the region of (620–640 nm). Maximal spectral variations appeared in the range of 711.16–758.27 nm for wet status products, which allowed to differentiate between the areas treated with copper-based products from the blanks without product. We can conclude that using hyperspectral imagery is possible to detect leave areas treated with copper-based fungicides immediately (wet treatment) after application.