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Esca disease, the most widespread grapevine trunk disease in Europe, is characterized by both chronic and acute forms. In both cases, alterations in the plant’s physiological processes are significant and lead to yield losses and/or plant death. Studies have highlighted the effects of a mixture of foliar fertilizers and seaweeds in reducing foliar symptoms and improving both the quantity and quality of yield. These effects have now been evaluated on additional cultivars and in other vineyard areas. Furthermore, for the first time, the activity of the fertilizer mixture in reducing apoplexy and the resulting vine mortality has been assessed. During the 2022–2023 biennium, in four vineyards of the Lambrusco cultivar in the Province of Reggio Emilia, Northern Italy, affected by both chronic and acute forms of the disease, foliar applications of the mixture were carried out at 10-day intervals starting from the “nine leaves unfolded” BBCH (Biologische Bundesanstalt, Bundessortenamt and Chemical industry) stage 19 up to the “berries developing color” BBCH stage 83. The results confirmed the activity of the fertilizer mixture in reducing chronic symptoms, which appeared particularly pronounced in 2022, when rainfall quantity and distribution allowed regular development of phenological stages. In that year, in all vineyards, a reduction of approximately 50% and 60% in the incidence and severity of chronic leaf symptoms was recorded. Under these optimal growth conditions, treated vines generally showed superior yield and quality. Conversely, in 2023, characterized by heavy rains, smaller effects on foliar symptoms and no improvements in yield were observed. Applications of the mixture resulted in a significant reduction in apoplexy and, consequently, vine mortality, as verified in 2024. This effect did not appear to be influenced by climatic conditions. This study confirms that applications of the mixture aimed at reducing symptom expression and yield damage are a valid addition to the few available control practices. The positive effects observed on the acute form for the first time require further investigation.

Fomitiporia mediterranea M. Fisch. (Fmed) is a basidiomycete first described in 2002, and was considered up to then as part of Fomitiporia punctata (P. Karst) Murrill. This fungus can degrade lignocellulosic biomass, causing white rot and leaving bleached fibrous host residues. In Europe Fmed is considered the main grapevine wood rot (Esca) agent within the Esca disease complex, which includes some of the most economically important Grapevine Trunk Diseases (GTDs). This review summarises and evaluates published research on Fmed, on white rot elimination by curettage or management by treatments with specific products applied to diseased grapevines, and on the relationship between wood symptoms and Grapevine Leaf Stripe Disease (GLSD) in the Esca disease complex. Information is also reviewed on the fungus biology, mechanisms of pathogenicity, and their possible relationships with external foliar symptoms of the Esca disease complex. Information on Fmed control strategies is also reviewed.

Tools for robust identification of crop diseases are crucial for timely intervention by farmers to minimize yield losses. Visual diagnosis of crop diseases is time-consuming and laborious, and has become increasingly unsuitable for the needs of modern agricultural production. Recently, deep convolutional neural networks (CNNs) have been used for crop disease diagnosis due to their rapidly improving accuracy in labeling images. However, previous CNN studies have mostly used images of single leaves photographed under controlled conditions, which limits operational field use. In addition, the wide variety of available CNNs and training options raises important questions regarding optimal methods of implementation of CNNs for disease diagnosis. Here, we present an assessment of seven typical CNNs (VGG-16, Inception-v3, ResNet-50, DenseNet-121, EfficentNet-B6, ShuffleNet-v2 and MobileNetV3) based on different training strategies for the identification of wheat main leaf diseases (powdery mildew, leaf rust and stripe rust) using field images. We developed a Field-based Wheat Diseases Images (FWDI) dataset of field-acquired images to supplement the public PlantVillage dataset of individual leaves imaged under controlled conditions. We found that a transfer-learning method employing retuning of all parameters produced the highest accuracy for all CNNs. Based on this training strategy, Inception-v3 achieved the highest identification accuracy of 92.5% on the test dataset. While lightweight CNN models (e.g., ShuffleNet-v2 and MobileNetV3) had shorter processing times (<0.007 s per image) and smaller memory requirements for the model parameters (<20 MB), their accuracy was relatively low (~87%). In addition to the role of CNN architecture in controlling overall accuracy, environmental effects (e.g., residual water stains on healthy leaves) were found to cause misclassifications in the field images. Moreover, the small size of some target symptoms and the similarity of symptoms between some different diseases further reduced the accuracy. Overall, the study provides insight into the collective effects of model architecture, training strategies and input datasets on the performance of CNNs, providing guidance for robust CNN design for timely and accurate crop disease diagnosis in a real-world environment.

A survey was carried out in 22 European and some non-European Mediterranean countries in 2015 and 2016, to gain insights into the main fungal grapevine trunk diseases (GTDs) in Europe. Information was obtained from 105 viticulture regions, representing approx. four million ha of vineyards. Vintage and table wines are the main industry products, followed by nursery plants and table grapes. Diverse scion cultivars are grown, with 13 cultivars providing 50% of survey respondent production, and Riesling Italico, Chardonnay, Cabernet Sauvignon and Merlot predominating. The five most used rootstocks are SO4, 110R, K5BB, 41B and 1103P, together representing about 50% of survey respondent production. Despite the diversity of grapevine training, Guyot and cordon remain the most widespread methods, and grapevines are mainly hand-pruned. The use of pneumatic shears and mechanical pruning is becoming more common in some countries. The survey questionnaire proposed a simplified set of symptoms or diseases occurring in mature vineyards [apoplexy, esca complex leaf symptoms (including Grapevine Leaf Stripe Disease, GLSD), dead cordon, Eutypa related dieback, Botryosphaeria or unidentified agent dieback, Phomopsis cane and leaf spot]. Apoplexy and esca/GLSD, defining the esca complex, were the most frequent and increasing syndromes in almost all countries, except Israel and the United Kingdom, where these diseases are not present or not recorded in the survey. Dead cordon and Phomopsis cane and leaf spot were mentioned as occurring in a large number of regions but not frequently. Within individual countries, the profile of GTDs varied according to the region, and to pedo-climatic and production conditions. GTDs on young vines were uncommon, but remain a subject of concern in some of European countries with large nursery production. This overview on spread and relevance of GTDs in Europe and related aspects will be a useful starting point for policy makers and for collaborative research on factors contributing to the increasing disease incidence of GTDs. Keywords. Esca complex, Botryosphaeriaceae, Phomopsis, Eutypa, dieback.

Two vineyards in the Abruzzo Region, central Italy, affected by grapevine leaf stripe disease (GLSD), were monitored for incidence and severity of foliar symptoms of the disease for 21 consecutive years (1994 to 2014). Each year, rainfall and temperature were recorded. Correlations between symptom incidence or severity and rainfall or temperature of different periods of the year or single months were assessed. July rainfall and temperature were highly correlated with incidence and severity of leaf symptoms. The vineyards were characterized by high longevity, vigour and yields, and a particular dynamic of GLSD. In the period following 2005, the year of peak vine mortality, there was a decrease of the expression of foliar symptoms, which was not correlated with both of the climate parameters. Greater mortality occurred for vines showing severe symptoms at the first appearance of GLSD than for vines with low severity.

Grapevine leaf stripe disease (GLSD) is a tracheomycosis caused by Phaeomoniella chlamydospora an Phaeoacremonium minimum. Impacts on yields of grapes were correlated with the incidence and severity of GLSD symptoms on vine canopies. In 2012 and 2013, vines in two vineyards were treated with nine applications of a mixture of leaf fertilizers containing calcium, magnesium and seaweed extracts. At different growth stages, leaves were sampled from treated and control plots of healthy, GLSD-asymptomatic, or GLSD-symptomatic vines and contents were measured of the phytoalexins trans-resveratrol, trans-ε-viniferin, trans-δ-viniferin and trans-pterostilbene. Grape ripening was also monitored from veraison to harvest during both vintages. The treatments caused significant reductions in canopy symptom expression. Increased phytoalexin contents were measured from 'fruit set' to 'berries developing colour' stages. Trans-resveratrol peak was recorded in asymptomatic diseased vines at the 'berries pea-sized' stage, and trans-ε-viniferin and trans-δ-viniferin increased at the 'berries beginning to touch' stage, compared to the contents recorded in untreated asymptomatic vines. From 'berries developing colour' to harvest, all treated vines had lower amounts of phytoalexins than the control ones. At harvest, treated healthy and symptomatic vines produced berries with similar amounts of total sugars compared to untreated vines. Treated asymptomatic vines produced berries with greater amounts of total sugars compared to the untreated vines. These results indicate that increased phytoalexin content recorded from 'fruit set' to 'berries beginning to touch' in asymptomatic vines treated with the mineral/seaweed mixture may reduce symptoms of GLSD.

What are the main findings? * Unmanned Aerial Vehicle (UAV)-based red–green–blue (RGB) imagery uncovers a previously unquantified pre-symptomatic phase of wheat stripe and leaf rust epidemics. * The pre-symptomatic phase was characterized by early changes in green–red spectral dynamics. * Flattening of RGB spectral slopes was a robust early-warning indicator of pathogen-induced physiological stress. Unmanned Aerial Vehicle (UAV)-based red–green–blue (RGB) imagery uncovers a previously unquantified pre-symptomatic phase of wheat stripe and leaf rust epidemics. The pre-symptomatic phase was characterized by early changes in green–red spectral dynamics. Flattening of RGB spectral slopes was a robust early-warning indicator of pathogen-induced physiological stress. What are the implications of the main findings? * RGB UAV imagery can help detect wheat stripe rust and leaf rust early, making it useful for both diagnosis and early-warning monitoring. * This framework supports targeted disease management decisions, with implications for precision agriculture, optimization of fungicide application, and scalable crop health monitoring. RGB UAV imagery can help detect wheat stripe rust and leaf rust early, making it useful for both diagnosis and early-warning monitoring. This framework supports targeted disease management decisions, with implications for precision agriculture, optimization of fungicide application, and scalable crop health monitoring. Remote sensing of crop diseases has traditionally focused on detecting visible symptoms, often limiting intervention to advanced stages of epidemic development. This study investigates whether high-resolution unmanned aerial vehicles (UAV)-based red–green–blue (RGB) imagery can reveal earlier physiological destabilization preceding visible symptoms of wheat stripe rust and wheat leaf rust. UAV imagery was acquired at four winter wheat-growing sites in Luxembourg during the 2018/2019 season. Temporal dynamics of green–red spectral slopes were analyzed and compared with ground-based disease severity observations to identify potential pre-symptomatic spectral signals. A consistent flattening of the green–red spectral slope was detected prior to a rapid increase in visually assessed severity for both diseases. However, the length of this pre-symptomatic window varied between the two diseases: it lasted 7 to 14 days for wheat stripe rust and 5 to 10 days for wheat leaf rust. Likewise, the reduction in spectral slope magnitude was slightly greater for wheat stripe rust (65–80%) than for wheat leaf rust (60–75%), indicating that the temporal lead time and intensity of the spectral response were disease-dependent. During the pre-symptomatic phase, the spectral dynamics reflected latent physiological changes rather than visible disease severity. Strong correlations emerged only after the epidemic transition. These findings demonstrate that UAV-based RGB imagery could capture a distinct pre-symptomatic phase of stripe rust and leaf rust epidemics in winter wheat. Interpreting RGB spectral dynamics as early-warning indicators rather than merely as static severity proxies can guide proactive disease monitoring and precision agriculture.

Grapevine leaf stripe disease (GLSD) is one of the most common diseases in the esca complex. Losses in grape yields and quality caused by GLSD are correlated with the severity of the leaf symptoms. The time course of phytoalexin levels was examined in vine leaves of two vineyards, in leaves of healthy, asymptomatic/diseased and symptomatic vines. Symptomatic leaves were further divided into four categories according to symptom severity: 1, 5% chlorosis; 2, 20% chlorosis; 3, 40% leaf surface covered with tiger stripes; or 4, 65% leaf surface covered with tiger stripes. Leaves were sampled at three growth stages: 'berries beginning to touch'; 'berries developing colour'; and 'berries ripe for harvesting'. The phytoalexins trans-resveratrol, trans-ε-viniferin; trans-δ-viniferin; and trans-pterostilbene were detected and assayed. Patterns of each of the phytoalexins were similar at each growth stage to those found earlier for trans-resveratrol, with an increased phytoalexin levels with increasing leaf symptom severity on the leaf blade, especially at the stages 'berries beginning to touch' and 'berries ripe for harvest'. A laboratory test was also carried out. Petioles of healthy grapevine leaves were immersed in culture filtrates of Phaeomoniella chlamydospora and then dipped in solutions of trans-resveratrol or trans-pterostilbene to assess the effects of these substances on the leaf blades. Adding these phytoalexins did not influence the effects of P. chlamydospora. These results indicated that phytoalexins increased in the leaves after GLSD symptoms appeared, and not before host response (phytoalexin synthesis) to control symptom development.

The Esca complex is one of the most destructive grapevine trunk diseases (GTDs) worldwide. Several factors, such as plant age, grapevine cultivar, or pattern of precipitation have been identified as possible driving forces of the disease. In the present study, a 4-year monitoring of grapevine leaf stripe disease (GLSD) symptoms in vineyards located in three areas in Rhineland-Palatinate was conducted. Vineyards of different age and planted with different cultivars, both traditional and new ones tolerant against Powdery and Downy Mildew, were chosen. All vineyards were equally subdivided into minimally and intensively pruned sections. The following aspects with regard to the training system were investigated: i) the occurrence of GLSD over the season; ii) the possible influence of cultivar, plant age and precipitation on symptom development; and iii) the possible impact of the training system on the incidence of GLSD. The seasonal patterns of symptom appearance in general were identical for the years 2015, 2016 and 2017. In 2018, however, the maximum peak of newly affected vines was reached about 4 weeks earlier, which is probably linked to the fast phenological development of the vines in this particular year. The training system did not affect the seasonal symptom appearance. All investigated parameters, i.e. cultivar, plant age and precipitation, were shown to have at least some influence on symptoms incidence, even though some of the results were inconsistent over the period of monitoring. Concerning the influence of the training system, in 2015 no differences between minimally pruned (1.8%) and intensively pruned (1.9%) vines were found. However, in the following year minimally pruned vines (6.9%) expressed significantly more symptoms than intensively pruned vines (4.9%). In the years 2017 and 2018 the opposite was the case. 2.6% and 2.4%, respectively, of the minimally pruned vines showed GLSD symptoms, while for the intensively pruned vines the mean values were 4.5% and 3.6%, respectively. Our study represents the first systematic GLSD related data collection in German vineyards over an extended period of time.

Grapevine leaf stripe disease (GLSD) is the most important syndrome of the esca disease complex. GLSD foliar symptoms are associated with grapevine yield losses and decline in vigour of host plants. Relationship between incidence and severity of GLSD symptoms and reductions grape quantity and quality has been demonstrated. In 2010–2012, foliar applications of mixtures of fertilizers based on calcium, magnesium and seaweed reduced symptom expression and increased yield quantity and quality. In the present study, mixture applications were carried out in 2013-2015 in different vineyards located in Abruzzo and Emilia-Romagna Regions (north-central Italy). These treatments reduced GLSD symptom incidence and severity, and applications of seaweed without calcium and magnesium was not effective. This confirmed involvement of the nutrients in the reduction of leaf symptom expression. Mechanical properties and absorbance difference measurements demonstrated increased berry quality from vines treated with the mixture. In trials carried out in 2015, the efficacy of the mixture applied in tank mix with other pest and disease control products was not reduced. We conclude that applications of calcium, magnesium and seaweed mixtures are effective for reducing the impacts of GLSD in vineyards.