Hyperspectral response of cape gooseberry (Physalis peruviana L.) plants inoculated with Fusarium oxysporum f. sp. physali for vascular wilt detection

Abstract

This study used greenhouse conditions to determine the hyperspectral responses of cape gooseberry (Physalis peruviana L.) plants inoculated with different Fusarium oxysporum f. sp. physali densities because the causal agent of vascular wilt generates great economic losses for farmers. A completely randomized design with four replicates was established. The evaluated treatments were inoculum densities 0.0, 1.0·103 and 1.0·106 conidia/mL of the pathogen. The inoculation was done with immersion of roots in conidia suspensions. The spectral response was directly measured on the plant leaves with a spectroradiometer. Non-invasive detection in the P. peruviana - F. oxysporum pathosystem with reflectance values was used with different spectral indices related to the visible and Red Edge, which were calculated and correlated with the disease variables. The treatments showed significant differences in the visible spectrum starting 14 days after inoculation with higher reflectance values. The chlorophyll index at the red edge (ChRE), the modified chlorophyll absorption index (MCARI), the simple ratio index (SR) and the Zarco & Miller index (ZM) showed highly significant correlations with the area under the disease progress curve for leaves (AUDPCL), leaf area and fresh weight of the aerial part of the plants. This study showed the potential of spectral patterns for the detection and study of Fusarium wilt in P. peruviana.

Early Detection of Wild Rocket Tracheofusariosis Using Hyperspectral Image-Based Machine Learning

“…The decrease in the absorbance of red light, therefore, is a sign of a non-effective quantum yield of PSII and PSI [89], which in the initial stage of the wilting progression can be explained by the degradation of chlorophyll a and peroxidation of the thylacoid plasmalemma due to the photoprotective action of ethylene induced by exposure to F. oxysporum toxin, accompanied also by a significant reduction in stomatal conductance [90]. Indeed, this evidence is consistent with the results of previous research concerning chlorophyll-associated VIs that are highly correlated with F. oxysporum disease progression on Physalis peruviana L. [91], and on banana [92]. These results highlighted the importance of capturing hyperspectral information on chlorophyll a transported by PSII in the phospholipidic membrane of thylacoids, to detect early infections of F. oxysporum f. sp.…”

Quinolizidine-Based Variations and Antifungal Activity of Eight Lupinus Species Grown under Greenhouse Conditions

“…Crops infected with this phytopathogen experience fusariosis, a plant disease that causes damage from leaf chlorosis to vascular necrosis [ 24 ]. These adverse effects produce significant economic losses in the agricultural sector [ 25 ], specifically in crops such as cape gooseberrys [ 26 ], bananas [ 27 ], carnations [ 28 ], lulos, and strawberries [ 29 ]. Fungicides such as dithane-M45, manzate 200WP, fitoraz, rovral-Flo, folicur EW, stroby SC, azoxystrobin, benomyl, carbendazim, and fludioxonil are currently used for the management of fusariosis [ 30 , 31 ].…”

Estimating chlorophyll and nitrogen contents in maize leaves (Zea mays L.) with spectroscopic analysis

“…2 chlorophyll content indicators, one of the more common indices is the Normalized Difference Vegetation Index (NDVI), which correlates with the amount of biomass, chlorophyll content and nitrogen content (Ranjan and Parida, 2020). There are other indexes for monitoring the nutritional status of crops, such as the Optimized Soil-adjusted Vegetation Index (OSA-VI) and the Near-infrared/red Ratio (NIR/red), which minimize the effect of soil reflectance on vegetation responses, as compared to NDVI, the Modified Chlorophyll Absorption Ratio (MCARI) and the Near-Infrared/green Ratio (NIR/green), which are more responsive to the leaf chlorophyll content (Daughtry et al, 2000;Giraldo-Betancourt et al, 2020).…”