Early detection of infected asymptomatic plants could prevent the dissemination of tomatobacterial canker throughout the crop and, thus, reduce associated economic losses. Reflectance spectroscopy has been proposed fo...Early detection of infected asymptomatic plants could prevent the dissemination of tomatobacterial canker throughout the crop and, thus, reduce associated economic losses. Reflectance spectroscopy has been proposed for the detection of diseases in plants, mainlycaused by foliar fungal pathogens. In contrast, bacterial canker is a vascular disease thatdoes not produce visible foliar symptoms until it is too late to avoid contagion to otherplants. The effects of the disease on the conductivity of the xylem have an impact onthe water content of the leaves;initially, a subtle effect that cannot be assessed with thenaked eye but can be evaluated by reflectance spectroscopy. The objective of this workwas to identify indices, based on the reflectance spectral signature of the plants, for thedetection of tomato plants affected by bacterial canker prior to the appearance of symptoms. To verify that the proposed methodology is applicable to a broad range of tomatogenotypes, two experiments were carried out with different tomato cultivars grown in potsand another on the ground in a greenhouse. Plants were inoculated with the pathogenicbacteria and the reflectance spectrum of the apical leaflet of two leaves per plant wereobtained before symptoms expression;several spectral indices were calculated from thereflectance spectra. Three indices, of the shortwave-infrared zone, allowed the detectionof bacterial canker inoculated plants in a fast and non-destructive way, up to one weekbefore symptoms were visible: Normalized Difference Water Index (NDWI), Simple Ratioof Water Index (SRWI) and Water Index 1 180 (WI1180). Our research demonstrates, forthe first time, the usefulness of spectral indices sensitive to water content for the identifi-cation of diseased plants. These indices arise as a promising tool for the early detection ofvascular plant diseases, that could be integrated into sustainable management plans.展开更多
基金This work was supported by the UBA[UBACyT20020170100695BA,UBACyT20020130100501BA]and ANPCyT[PICT 2015-0396].
文摘Early detection of infected asymptomatic plants could prevent the dissemination of tomatobacterial canker throughout the crop and, thus, reduce associated economic losses. Reflectance spectroscopy has been proposed for the detection of diseases in plants, mainlycaused by foliar fungal pathogens. In contrast, bacterial canker is a vascular disease thatdoes not produce visible foliar symptoms until it is too late to avoid contagion to otherplants. The effects of the disease on the conductivity of the xylem have an impact onthe water content of the leaves;initially, a subtle effect that cannot be assessed with thenaked eye but can be evaluated by reflectance spectroscopy. The objective of this workwas to identify indices, based on the reflectance spectral signature of the plants, for thedetection of tomato plants affected by bacterial canker prior to the appearance of symptoms. To verify that the proposed methodology is applicable to a broad range of tomatogenotypes, two experiments were carried out with different tomato cultivars grown in potsand another on the ground in a greenhouse. Plants were inoculated with the pathogenicbacteria and the reflectance spectrum of the apical leaflet of two leaves per plant wereobtained before symptoms expression;several spectral indices were calculated from thereflectance spectra. Three indices, of the shortwave-infrared zone, allowed the detectionof bacterial canker inoculated plants in a fast and non-destructive way, up to one weekbefore symptoms were visible: Normalized Difference Water Index (NDWI), Simple Ratioof Water Index (SRWI) and Water Index 1 180 (WI1180). Our research demonstrates, forthe first time, the usefulness of spectral indices sensitive to water content for the identifi-cation of diseased plants. These indices arise as a promising tool for the early detection ofvascular plant diseases, that could be integrated into sustainable management plans.
