The goal of TECNALIA in the project is the development of a new portable device based on photonicsthat will allow the early detection of mildew in the grape leaves foliar tissue.
The mildew is a disease caused by the Plasmopara vitícola pathogen, endemic in wet and warm climate cultivation areas. When the environmental conditions are favourable for the development of the disease, the vineyards are always treated with fungicides, although the presence of the disease is the plans in not known with certainty. Apart from the economic impact for the winery, this practice becomes a risk for the farmer, since fungicide residues remain in the soils and berries, affecting the global quality of the grape juice and wine.
The 2009/108/CE directive, has as objective achieving a sustainable use of insecticides, reducing the risks and effects of insecticides in the human health and the environment and promoting the integrated management of plagues and alternative solutions, such as non-chemical techniques alternatives to insecticides.
With respect to the magnitude of the wine sector, there are around 7.000 wineries in Spain and around 20.000 al around the world (www.oiv.org).
The advantages of using a portable device in the sector would be:
- Early detection of the pathogen, before the symptoms are visible to the human eye.
- Reduction of the sources of inoculation responsible of the dissemination of the disease spores.
- Increasing efficacy and efficiency in the use of fungicides/insecticides.
- Additional knowledge for the selection of the fungicide, depending on the detected life-cycle stage of the fungus.
- Reduction of the damages caused by the fungus in vegetal tissues.
- Reduction of the total number of treatments and doses applied in the wine fields. Avoid the increasing resistance of the pathogen to phytosanitary products in the wine fields.
- Wine field technicians in charge of the management of the vineyard.
- Companies dedicated to the advisory on pathogens and plague control management.
- Companies providing machinery for the application of phytosanitary products.
Tests and Results by May 2015
The execution of the test with photonics-based technologies has required the preparation of different tissues samples tests. These has been inoculated in different times (considered as classes), and generated under controlled and repetitive conditions so the results are comparable.
The test sets contain samples of the grape leaves in different stages of evolution of the disease, managed controlling the number of days since the inoculation (dpi – days post inoculation): high presence of the fungus in the leaf surface (5-6 dpi), medium infection (2-3 dpi) and early infection (1dpi). Additionally, there are also healthy samples of each dpi to be utilized as a reference.
During the project time executed so far, several techniques base on spectrometry and hyperspectral imaging have been under study. The goal of this study was to analyse the viability of identifying and classifying the fungus with the various ranges of the light electromagnetic spectrum using different optical configurations. Diverse algorithms have been developed with the goal of discriminating infected from healthy leaves using the captured spectra. The tests have been repeated with different samples tests with the aim of validating and corroborating the results of the analysis.
Taking into consideration the obtained results, a new portable device based on spectrometry is currently under development in the project. The goal in the following months of the project is evaluating the device capacities in real field conditions, analyse the different possible scenarios and environments and make the necessary adjustments in the technology, ensuring a high quality of the results.