Disease Of Grapevine Research Articles

Biofilm formation by the fungus Phaeomoniella chlamydospora: a causal agent of esca disease of grapevine

The present study suggests that the Esca pathogenic fungus Phaeomoniella chlamydospora can form biofilm in vitro and possibly in the grapevine host tissues. This phenomenon was revealed by the detailed examination of the development of three isolates of the fungus, showing dimorphic growth with the formation of yeast-like cells in the center, which were embedded in a polysaccharide-rich extracellular matrix, and filamentous growth at the colony margins. The colonies produced acetate, which chemical proved to be an enhancer of yeast-like growth and extracellular matrix production. The dynamic of biofilm formation was correlated with the ability of the strains to produce acetate, suggesting that it acts as a quorum sensing molecule in the process. The dimorphic growth of P. chlamydospora was also demonstrated in host tissues as a sole nutrient source, suggesting that biofilm can be produced in planta and take part in the pathogenesis of Esca. The biofilms formed by the fungus may contribute to the previously reported inhibition of sap flow in the infected plants, while its quorum sensing-mediated nature may partly explain the controversial literature data on the occurrence of the pathogen and symptom severity in the host.

Farmer’s knowledge, perception, and practices in managing insect pests and diseases of grapevine in Morocco

An evaluation of pest and disease management practices was conducted among 181 grapevine farmers across five key viticulture regions in Morocco from 2019 to 2022. The primary objectives were to assess farmers’ knowledge, perceptions, and practices and to examine their impact on grapevine productivity. A diverse range of grape varieties was noted, with over 21 varieties yielding from 10 to 30 t/ha. Disease monitoring was reported by 97.4% of the winegrowers within their vineyards, but only 12.1% actively scouted for grapevine trunk diseases. A diverse array of over 40 active ingredients was evaluated against each reported disease. For instance, gray mold (Botrytis cinerea) was mainly treated with boscalid + pyraclostrobin (72%), mancozeb + thiophanate methyl (71%), cyprodinil (69%), and fenthion (69%). As for the downy mildew (Plasmospora viticola), seven active ingredients were significantly been highlighted including cymoxanil + mancozeb (72%), hexaconazole 5% (71%), iprodione (69%), and mancozeb (72%), while maneb (69%) was the most adopted treatment for black rot (Guignardia bidwellii) disease. Some of these treatments showed positive correlations with each other in targeting multiple pests. Identification and control of pests and diseases were often based on damage symptoms rather than on recording causal agents. Respondents were aware of the most common foliar diseases and pests. Multivariate analyses showed that there is a strong relationship between farmers’ characteristics and their overall knowledge of pests and diseases. However, farmers’ knowledge of major grapevine trunk diseases was relatively low and management practices were inadequate. The study underscores the critical role of improved practices and knowledge in mitigating the high variability in grapevine productivity experienced by Moroccan farmers.

Cardamom Plant Disease Detection Approach Using EfficientNet

Cardamom is a queen of spices. It is indigenously grown in the evergreen forests of Karnataka, Kerala, Tamil Nadu, and the northeastern states of India. India is the third largest producer of cardamom. Plant diseases cause a catastrophic influence on food production safety; they reduce the eminence and quantum of agricultural products. Plant diseases may cause significantly high loss or no harvest in dreadful cases. Various diseases and pests affect the growth of cardamom plants at different stages and crop yields. This study concentrated on two diseases of cardamom plants, Colletotrichum Blight and Phyllosticta Leaf Spot of cardamom and three diseases of grape, Black Rot, ESCA, and Isariopsis Leaf Spot. Various methods have been proposed for plant disease detection, and deep learning has become the preferred method because of its spectacular accomplishment. In this study, U2 -Net was used to remove the unwanted background of an input image by selecting multiscale features. This work proposes a cardamom plant disease detection approach using the EfficientNetV2 model. A comprehensive set of experiments was carried out to ascertain the performance of the proposed approach and compare it with other models such as EfficientNet and Convolutional Neural Network (CNN). The experimental results showed that the proposed approach achieved a detection accuracy of 98.26%. Index Terms — Cardamom plant, deep learning, machine learning, neural networks, plant pathology

Virulence Comparison of a Comprehensive Panel of Xylella fastidiosa Pierce's Disease Isolates from California.

Xylella fastidiosa, the causal agent of Pierce's disease of grapevine, has been found in all major grape-growing regions in California, U.S.A. Large collections of X. fastidiosa isolates are available from these areas, which enable comparative studies of pathogen genetic traits and virulence. Owing to the significant resource requirements for experiments with X. fastidiosa in grapevine, however, most studies use only a single isolate to evaluate disease, and it is not clear how much variability between isolates impacts disease development in experimental or natural settings. In this study, a comprehensive panel of X. fastidiosa isolates from all California grape-growing regions was tested for virulence in susceptible grapevine and in the model host plant, tobacco. Seventy-one isolates were tested, 29 in both grapevine and tobacco. The results of this study highlight the inherent variability of inoculation experiments with X. fastidiosa, including variation in disease severity in plants inoculated with a single isolate, and variability between experimental replicates. There were limited differences in virulence between isolates that were consistent across experimental replicates, or across different host plants. This suggests that choice of isolate within the X. fastidiosa subsp. fastidiosa Pierce's disease group may not make any practical difference when testing in susceptible grape varieties, and that pathogen evolution has not significantly changed virulence of Pierce's disease isolates within California. The location of isolation also did not dictate relative disease severity. This information will inform experimental design for future studies of X. fastidiosa in grapevine and provide important context for genomic research.

Bioprotective effects of different Plant Extracts and Essential Oils against Rhizopus stolonifer and Aspergillus niger causing Post Harvest decay in Grapes

The grapes (Vitis vinifera) are one of the largely consumed fruits in the world. Grape production in Pakistan has increased in the recent years. These are mainly consumed fresh or as dried raisins. Grapes are highly perishable, which makes them liable to rot during transport, storage, and marketing. The perishable nature of grapes leads to a considerable amount of post-harvest loss. The production and quality of grapes are adversely affected by several abiotic and biotic factors. Two different cities Pishin (Balochistan) and Faisalabad (Punjab) fruit market and stores were selected to collect rotten grapes. The fungal pathogens isolated were identified as A. niger and R. stolonifers. The pathogenicity of isolated pathogens was assessed at different temperatures (5, 20, and 30 °C) on the Thompson seedless grape variety. Infection and proliferation of fungi were found conducive at 30°C. As antifungal agents, three organic origin oils, neem, cinnamon, and clove oils with levels i.e., 500, 1000, 2000 ppm as well as marigold and neem extracts with diverse concentrations of like 12.5, 25, and 50% were employed. Among these organic compounds, cinnamon and clove oils at 2000 ppm exhibited 6.54% and 15.3% decay against A. niger, respectively. Meanwhile, against R. stolonifer, cinnamon and clove oils at 2000 ppm exhibited 12.22% and 6.74% decay, respectively. This study's findings focus on the effectiveness of both essential oils and plant extract in significantly delaying the decay process caused by fungal pathogens. The present study underscores the protective ability of the plant extracts and natural oils which could be a way forward for eco-safe management of post-harvest diseases of grapes before they reach the market.

The plant germplasm and herbarium (WIR) collections maintained at VIR as contributors to grape genetic diversity conservation, expansion and utilization

Improving the standards of collecting and maintaining valuable genetic resources accessions and information about them is currently of crucial importance for the successful development of the world viticulture in the light of the challenges caused by the spread of grape diseases and climate change. This review briefly characterizes the global grapevine gene pool, approaches to its conservation, including base and duplicate conservation techniques, and the current status and prospects of the progress in in vitro and cryogenic preservation methods. The genetic potential of grape wild relatives is assessed focusing on particular species as sources of resistance genes to biotic and abiotic stressors. Achievements in the application of gene editing technologies to increase grape resistance to diseases are discussed. It is noted that a common practice at this stage is to knock out the genes responsible for grapevine susceptibility to diseases, whereas a more advantageous approach in the future will be to make targeted changes in the grape genome based on the knowledge of resistance genes in its wild relatives. Therefore, grape wild relatives need to be studied thoroughly using modern methods of forward and reverse genetics. Regarding the issues of grape genetic diversity conservation and expansion at the current technological stage, the status and significance of the plant germplasm and herbarium (WIR) collections held by VIR are scrutinized in detail. Authentication of grape germplasm accessions is marked as important, along with the role of the WIR herbarium, a unique collection incorporating physical carriers of reference genetic information on the national grapevine gene pool. Promising trends in the development of the WIR herbarium are outlined in connection with the establishment and preservation of nomenclature standards for domestic grape cultivars.

First Report of Neofabraea actinidiae causing a Cranberry Fruit Rot in Oregon.

Cranberry (Vaccinium macrocarpon, L.) is a commercial small fruit that is native to North America. Oregon ranks fourth in cranberry production in the U.S.A. with 1052 Ha of cranberry beds and annual production of 23,590 metric tonnes (USDA NASS 2021). Cranberry fruit rot diseases are caused by a complex of 15 fungal pathogens belonging to 10 genera (Polashock et al. 2017). In fruit rot surveys of 'Stevens' cranberry beds in Coos and Curry Counties, Oregon, berries were collected before harvest and sorted by symptoms (e.g. softening, shriveling, or discoloration). Cranberries with field rot symptoms were surface-disinfested and lesion margin tissue placed on V8 agar. Cultures were incubated at room temperature and outgrowing fungi were transferred twice onto fresh V8 agar to obtain single isolates. Storage rots that developed on asymptomatic cranberries held at 4°C for 8 weeks were processed similarly. Since 2017, we periodically isolated Neofabraea actinidiae, which is not a member of the cranberry fruit rot complex, from rotted cranberries (Polashock et al. 2017). In 2022, N. actinidiae was isolated from 22% of 45 cranberries collected from an organically managed farm and developed storage rot and from 6% of 50 storage-rot cranberries from three conventionally managed farms. Symptoms associated with N. actinidiae on 'Stevens' cranberries often include softening and brown tissue surrounded by a yellow-colored ring. On V8 agar, N. actinidiae grew as compact white circular colonies with dense aerial hyphae near the center and accompanied by a red pigment in the agar. Pink-colored mucoidal irregular conidiomata often developed on the colony after 3 weeks. Conidia were hyaline, aseptate, and ellipsoidal to fusiform ranging from 7.5 to 12.6 µm long X 3.5 to 5.6 µm wide (n=100). Genomic DNA was extracted from N. actinidiae isolates from cranberries in 2017 and 2022. β-tubulin and the ITS 5/4 region were amplified and sequenced with primers Bt-T2m-Up/Bt-LEV-Lo1 and ITS5/ITS4 using conditions of de Jong et al. (2001) and White et al. (1990), respectively. Sequences were deposited in NCBI Genbank (Accessions: OR606303, OR606305, OR606306, & OR606309 for ITS; OR610314, OR610316, OR610317, & OR610320 for β-tubulin). BlastN analysis of β-tubulin (695 bp) and ITS (489-490 bp) had a 99.6 to 99.8% and 99.8 to 100% identity, respectively, to Neofabraea actinidiae (CBS 121403) (Accession numbers: KR859285 β-tubulin and KR859079 ITS). Phylogenetic analysis of concatenated sequences using Tamura-Nei neighbor-joining (Tamura et al. 2004) confirmed identity of cranberry isolates as N. actinidiae. Koch's Postulates were confirmed with four N. actinidiae isolates from cranberry. Agar or hyphal plugs were placed in a 3 mm wound on the side of six surface-disinfested, asymptomatic berries and incubated in a moist chamber at 20°C for 15 days or 4°C for 55 days. Similar symptoms developed on each berry inoculated with N. actinidiae, but not agar alone. The fungus was recovered from symptomatic tissues and identity confirmed by colony morphology. N. actinidiae causes a ripe rot and storage rot in kiwifruit and is one of the species causing Bull's Eye Rot of pome fruits (Tyson et al. 2019). Cryptosporiopsis actinidiae (anamorph) was isolated from cranberries roots in British Columbia, CA, but considered unlikely to be the causal agent of dieback disease of cranberry vines (Sabaratnam et al. 2009). We have demonstrated that N. actinidiae causes a cranberry fruit rot in beds and in storage. Its prevalence, associated fruit rot symptoms, and disease incidence will continue to be monitored.

Enhancing Weighted Averaging for CNN Model Ensemble in Plant Diseases Image Classification

Deep learning, especially convolutional neural networks (CNN), has gained traction in the field of image classification. In the specific case of plant disease classification, improving the accuracy and reliability of image classification is paramount. This paper delves into the ensemble prediction technique using a weighted soft-voting method. Instead of assigning a generalized weight to each CNN model, our approach emphasizes giving weights to each label's prediction within every individual model. We employed three esteemed CNN architectures for our experiments: DenseNet201, InceptionV3, and Xception focusing on classifying various diseases affecting grapes. By harnessing transfer learning coupled with end-to-end fine-tuning, we achieved a streamlined and efficient training process. Notably, the f1-score for each grape disease class was used as a parameter for weight determination and as a metric for the final evaluation. In our study, the newly proposed method was tested across various datasets and ensemble scenarios, demonstrating its effectiveness by not only outperforming the conventional soft-voting and prevalent weighted soft-voting methods, which achieved best scores of 95.68% and 95.81% respectively, but also by achieving a remarkable accuracy of 96.56%. This method's efficacy is heightened when ensemble models exhibit distinct characteristics; the more varied the model characteristics, the more enhanced the ensemble results.

Impact of Wood-Boring Larvae of Xylotrechus arvicola (Coleoptera: Cerambycidae) on Mechanical Properties of Vitis vinifera Plants

Xylotrechus arvicola represents a significant insect pest impacting Vitis vinifera within the principal wine-producing territories of the Iberian Peninsula. The larvae of this species bore into grapevine wood, resulting in significant structural and biomechanical deterioration to the plant. Compressive and flexural tests were conducted to assess the mechanical properties of wood affected by X. arvicola. Compressive and flexural strength exhibited a decline with the escalation of the Total Damaged Surface Area (TDSA) of the samples, ranging from 0.31% to 0.73% in trunks and from 0.04 to 0.76% in branches, irrespective of the wood moisture content (fresh and dry). The most significant reduction in resistance occurred in affected dry trunks and branches. Notably, the deflection at break for dry samples was lower compared to fresh samples (65.00 and 97.85 mm, respectively). Moreover, the deflection at break for affected fresh samples (164.37 mm) significantly surpassed that of unaffected fresh samples (72.58 mm) and affected dry samples (37.50 mm). It is noteworthy that a higher percentage of TDSA coincided with diminished wood resistance. The percentage of fungal growth symptoms observed in affected wood samples was 66.66% for dry trunks, 75.00% for fresh branches, and 60.00% for dry branches. The damage inflicted by larvae facilitated the spread of grapevine diseases via emergence of holes created by insects upon exiting the wood and through the larval galleries connected to them. This damage also altered the mechanical properties of grapevine plants, with fresh branches exhibiting the most pronounced effects.

Multiclass classification of diseased grape leaf identification using deep convolutional neural network(DCNN) classifier

The cultivation of grapes encounters various challenges, such as the presence of pests and diseases, which have the potential to considerably diminish agricultural productivity. Plant diseases pose a significant impediment, resulting in diminished agricultural productivity and economic setbacks, thereby affecting the quality of crop yields. Hence, the precise and timely identification of plant diseases holds significant importance. This study employs a Convolutional neural network (CNN) with and without data augmentation, in addition to a DCNN Classifier model based on VGG16, to classify grape leaf diseases. A publicly available dataset is utilized for the purpose of investigating diseases affecting grape leaves. The DCNN Classifier Model successfully utilizes the strengths of the VGG16 model and modifies it by incorporating supplementary layers to enhance its performance and ability to generalize. Systematic evaluation of metrics, such as accuracy and F1-score, is performed. With training and test accuracy rates of 99.18 and 99.06%, respectively, the DCNN Classifier model does a better job than the CNN models used in this investigation. The findings demonstrate that the DCNN Classifier model, utilizing the VGG16 architecture and incorporating three supplementary CNN layers, exhibits superior performance. Also, the fact that the DCNN Classifier model works well as a decision support system for farmers is shown by the fact that it can quickly and accurately identify grape diseases, making it easier to take steps to stop them. The results of this study provide support for the reliability of the DCNN classifier model and its potential utility in the field of agriculture.

Identification of Laccase Genes in Grapevine and Their Roles in Response to Botrytis cinerea

Laccases are the key enzymes responsible for plant lignin biosynthesis and responses to environment stress. However, the roles of LAC genes in plant disease resistance are still largely unknown, especially in grapevine, one of the most important horticultural crops in the world. Its quality and yield are very vulnerable to gray mold disease caused by Botrytis cinerea. In total, 30 VvLAC genes were identified and found to be unevenly distributed on seven chromosomes; they were classified into seven groups based on phylogenetic analysis according to the criteria applied in Arabidopsis thaliana. Collinearity and synteny analyses identified some orthologous gene pairs in Vitis vinifera and a few paralogous gene pairs among grape and peach. The VvLAC gene family has diverse gene structures and a highly conserved motif composition. The prominent presence of the MYB cis-elements in each VvLAC promoter highlighted MYB transcriptional factors as the main regulators of VvLAC genes. Furthermore, twenty-five VvLAC genes with functional redundancy are probably implicated in grape lignin biosynthesis. The expression patterns of the LAC genes in grape leaves of Chinese wild V. amurensis ‘Shuangyou’ (SY), a germplasm highly resistant to B. cinerea, were investigated through transcriptomic data and qRT-PCR verification. Combined with the phylogenetic analysis, with AtLACs participating in lignin metabolism, and the cis-element analysis, VaLAC14, VaLAC19, VaLAC24 and VaLAC30 were identified as key candidate genes for lignin biosynthesis in the grape response to B. cinerea. This study supplies a comprehensive understanding of the classification, evolution, structure and responses of the grape LAC genes against B. cinerea. It also provides valuable genetic resources for functional characterization towards enhancing grapevine disease resistance.

Present Status of Viral Diseases of Grapevine (<i>Vitis Vinifera</i> L.) and their Management Strategies in India

Grapevine is an important fruit crop cultivated in temperate, subtropical and tropical conditions in India. The maximum share in area, production, and productivity of grapes is governed by four states viz. Maharashtra, Karnataka, Tamil Nadu and Andhra Pradesh. The sudden and drastic changes in climatic conditions and the emergence of diseases have made grapevine cultivation more challenging. Fungal and bacterial diseases are the major constraints in the grapevine production. Besides, some viral diseases like Grapevine Leafroll Disease (GLD) and Rupestris Stem Pitting Associated Diseases (RSPD) are reported in Indian vineyards. Although the presence of Grapevine Leafroll-Associated Viruses (GLRaVs) viz., GLRaV-1, GLRaV-3, and GLRaV-4 are known the impact on yield and quality of the grapes is not yet studied. Similarly, the Rupestris Stem Pitting Associated Virus (RSPaV) is known to infect the Indian vineyards of different locations but a complete understanding of their overall impact on vineyards is lacking. Therefore, it is presumed that fewer or no losses occur due to GLD and RSPD diseases. There is a strong need for hours to study the impact of known viruses on physiological and yield contributing parameters. In addition to this, robust, rapid and reliable diagnostic techniques are required for the detection of known and unknown viruses. The presence of new and emerging viruses in the Indian vineyards cannot be overlooked. Further, for the management of the viruses and avoiding their spread, the availability of Disease-Free Quality Planting Material (DFQPM) is a prerequisite. To produce DFQPM, various tissue culture techniques need to be standardized for the elimination of the virus/es from the diseased vines. The Tissue Culture-Raised Quality Planting Material (TCQPM) needs to be further tested for genetic purity (true-to-type) and virus indexing to confirm DFQPM. By considering the importance of DFQPM, recently, the National Horticulture Board (NHB), Govt. of India in association with the Asian Development Bank (ADB) has initiated a National Mission on Clean Plant Programme. The implementation of this initiative is more challenging and expected to open different avenues of research and development in the production of DFQPM for the growers. This is an important and timely beginning of the production of DFQPM.

Breeding new seedless table grapevines for a more sustainable viticulture in Mediterranean climate.

The growing demand for sustainable and environmentally friendly viticulture is leading to a multiplication of breeding programs aimed at obtaining vines that are resistant to powdery mildew (PM) and downy mildew (DM), the two most damaging vine diseases. In Puglia, the most important Italian region for the production of table grapes, an extensive crossing program was launched in 2015 with 113 crosses, including elite table varieties, seedless varieties, and resistant varieties. The main seedling production parameters were measured for each cross. In particular, berries harvested as well as the number of seeds and seedlings obtained were considered. Approximately 103,119 seedlings were obtained and subjected to marker-assisted selection for seedlessness using the marker VvAGL11 and for resistance to PM and DM with appropriate markers. Approximately one third (32,638) of the progenies were selected as putative seedless and seventeen thousand five hundred-nine (17,509) were transferred to the field for phenotypic evaluation, including 527 seedless individuals putatively resistant, of which 208 confirmed to be resistant to DM, 22 resistant to PM, and 20 individuals that combined resistance and seedlessness traits. The work discusses the effects of parental combinations and other variables in obtaining surviving progeny and pyramiding genes in table grapes and provides useful information for selecting genotypes and increasing the efficiency of breeding programs for seedless disease-resistant grapes.

Morphological, molecular biology and pathological characterization of fungi causes root rot on grapevine

Background Grapevine is subjected to attack by several of soilborne fungi causing root-rot diseases that lead to limit the production of grapevine. Objective This study aimed to investigate the morphological, molecular identification, and pathogenic potential of fungi that causes root-rot disease of grapevine in Egypt. Materials and methods Isolation of fungi causing root rot of grapevine plants from the samples of diseased roots of different cultivars, i.e., crimson, superior, and flame seedless. Identification according to characterizations of morphological, cultural, and molecular biology based on internal-transcribed spacer 1 (ITS1). Pathogenicity tests of fungal isolates on grapevine plants under greenhouse conditions. Root-rot incidence, disease severity, and plant growth characteristics were determined. Results and conclusion Isolation traits from affected grapevine trees with different grape varieties in Egypt’s El-Nobaria Province, El-Behira Governorate, yielded eighteen isolates of four fungal genera. Fusarium spp. was the most fungal genus highly frequent on all cultivars tested and colonization (100%) on root-rot tissue of superior and flame-seedless cultivars, then (75%) on Crimson cultivar. While Lasiodiplodia spp. was recorded with moderate frequency and high colonization (100%) on rotten tissue of Crimson cultivar followed by (75%) in both flame-seedless and superior cultivars. As opposed to that, fungi of Macrophomina phaseolina followed by Rhizoctonia solani had the least frequency and colonization percentage. Isolates of fungi were identified according to morphological characteristics, cultural, and molecular biology based on internal-transcribed spacer-1 (ITS1) sequencing and conserved in GenBank with accession numbers from (ON037457.1 to ON037474.1). Fungal isolates were varied for causes of root rot on grapevine plants and their reduction effect on the characteristics of growth of flame-seedless cultivar. Fusarium solani isolate (ON037462.1) was the most pathogenic isolate that caused (100%) of root rot, high disease severity, and highly significant reduced grapevine plant growth characteristics followed by isolates of Lasiodiplodia theobromae (ON037474.1). In this respect, a new isolate of fungal species was hosting grapevine plants, i.e., two isolates each of F. chlamydosporum, F. brachygibbosum, one isolate of F. ipomoeae, and one isolate of L. exigua are the new causal pathogens of root-rot disease on grapevine as the first report in Egypt.

First Report of Cucurbit Yellow Vine Disease Caused by Serratia marcescens on Cucurbit Crops in Iowa

Cucurbit yellow vine disease (CYVD) is caused by Serratia marcescens, vectored by squash bugs (Anasa tristis), and is an emerging disease in many parts of the U.S. CYVD can cause 100% yield losses in cucurbits (Bruton et al., 2003). In the summer of 2021, at the Iowa State University Horticultural Research Station (HRS) in Gilbert, Iowa, we observed leaf yellowing, vine decline, and honey-brown discoloration of the phloem of acorn squash (Cucurbita pepo cv. Table Ace) plants in research fields that were infested with squash bugs. In 2022, we observed similar symptoms on pumpkin (Cucurbita maxima cv. Howden) and muskmelon (Cucumis melo cv. Athena) in different fields at the HRS and on giant pumpkins (Cucurbita maxima cv. Prizewinner) in Jones and Ringgold counties. For up to 3 symptomatic plants of each cucurbit species per location, a 20-cm-long stem section immediately above the soil line was excised, surface sterilized by immersion in 10% sodium hypochlorite and 70% ethanol for 2 min each, then triple rinsed in sterile water. The interior of the cross-section tissue was blotted on Luria agar amended with cycloheximide (100 μg/ml) and tetracycline (20 μg/ml) (Stock et al. 2003). Whitish translucent colonies developed after incubation at 28°C for 48 h. The genomic DNA of three isolates from symptomatic plants of muskmelon (MK01), pumpkin (HFP01), and giant pumpkin (AP01), was extracted using the DNeasy Blood and Tissue Kit (Qiagen, Germantown, MD). S. marcescens species-specific primers YV1 (5’-GGGACTTGCTCCCCGG-3’) and YV4 (5’-AACGTCAATTGATGAACGTATTAAGT-3’) (Bruton et al. 2003) were used to amplify part of the 16S rDNA gene, and the primers specific to S. marcescens CYVD strains A79F/A79R (Zhang et al., 2005) were used to amplify part of a major facilitatory superfamily (MFS) transporter gene strain. The sequences of the 16S rRNA PCR product for the three isolates were identical and were deposited in NCBI under Accession OR963533. They shared 100% (395/395 nt) identity with other CYVD strains (Rascoe et al. 2003) and those of other S. marcescens strains in NCBI. The sequences of the amplified region of the MFS transporter gene of the three isolates (NCBI Accession OR962261) were identical and showed a 98.8% (319/323 nt) identity to that of non-CYVD-causing S. marcescens strains, such as N10A28 (Accession CP033623.1). Koch’s postulates were fulfilled by inoculating C. pepo cv. Zephyr plants with either strain HFP01 or phosphate buffer saline (PBS) (10 plants per treatment) 1 wk after seeding by injecting 300 µl of bacteria (~108 CFU/ml) or PBS using a syringe needle. Plants were incubated at 28°C in a growth room for 4 wks. CYVD symptoms similar to those observed in the field developed on 7 out of 10 plants inoculated with strain HFP01 in one study, and 9 out 10 plants in a replicate study, with none of the PBS-inoculated plants showing CYVD symptoms. Bacteria were isolated from the symptomatic plants with selection on tetracycline. The PCR fragments amplified with YV1/YV4 and A79F/A79R were the same size as those of the pre-inoculation strain HFP01. To our knowledge this is the first report of CYVD in Iowa and in the Upper Midwest of the U.S. CYVD is a devastating disease that poses a significant threat to cucurbit production. This report can serve as an alert for the region’s growers and for the development of effective management practices.

Identification of he-ne laser based mutation induced bacteria against grape disease

In the present study six bacterial strains from the soil of grape orchard were isolated and identified. Their antagonistic ability against Uncinula necator and Plasmopara viticola which cause downy mildew and powdery mildew of grapes, respectively were studied. Through phenotypic, physiological and biochemical studies, SF6 strain was identified as Bacillus subtilis which can effectively inhibit the growth of Uncinula necator and Plasmopara viticola of grapes. In order to enhance the antagonistic ability of the SF6 strain, mutation was induced by He-Ne laser radiation and, six mutant strains were obtained. Among the six mutant strains, SF66 showed the strongest antagonistic activity to Uncinula necator and Plasmopara viticola of grapes with its genetic stability. The finding of this research provides important impetus for the development of beneficial antagonistic microorganisms through He-Ne laser radiation breeding. Bangladesh J. Bot. 53(1): 33-40, 2024 (March)

基于改进YOLOv8s的实时葡萄病害检测模型

This research is dedicated to enhancing the accuracy and processing speed of grape disease recognition. As a result, a real-time grape disease detection model named MSCI-YOLOv8s, based on an improved YOLOv8s framework is proposed. The primary innovation of this model lies in replacing the backbone network of the original YOLOv8s with the more efficient MobileNetV3. This alteration not only strengthens the ability of the model to capture features of various disease manifestations in grape leaf images but also improves its generalization capabilities and stability. Additionally, the model incorporates the SPPFCSPC pyramid pooling structure, which maintains the stability of the receptive field while significantly enhancing processing speed. The integration of the CBAM attention mechanism further accentuates the ability of the model to identify key features, substantially increasing the accuracy of disease detection. Moreover, the model employs Inner-SIoU as the loss function, optimizing the precision of bounding box regression and accelerating model convergence, thereby further enhancing detection efficiency. Rigorous testing has shown that the MSCI-YOLOv8s model achieves an impressive average precision (mAP) of 97.7%, with an inference time of just 37.2 milliseconds and a memory footprint of 39.3 MB. These advancements render the MSCI-YOLOv8s not only highly efficient but also extremely practical for real-time grape disease detection, meeting the actual demands of grape orchard disease identification and demonstrating significant potential for application.

Occurrence of grapevine yellow speckle viroid 2 and Australian grapevine viroid in Idaho grapevines.

Grapevine yellow speckle viroid 2 (GYSVd-2; Pospiviroidae, Apscaviroid) causes yellow speckle disease in grapevine (Koltunow et al. 1989) and was found in Australia, Iran, Italy, China, and Nigeria (Koltunow et al. 1989; Habili 2017; Zongoma et al. 2018). In the U.S., GYSVd-2 was found in the State of Washington (Vitis vinifera L. cv. Merlot; Alabi et al., 2012). Australian grapevine viroid (AGVd; Pospiviroidae, Apscaviroid) was reported in Australia, Italy, China, Tunisia, Iran, and in the U.S. wine grapes (V. vinifera) (Habili 2017). In the U.S., AGVd was reported from California (Al Rwahnih et al. 2009), from Washington State (V. vinifera cv. Syrah; GU327604), and from the State of New York (an unknown cv. of V. vinifera; KY081960). In Idaho, two other viroids, hop stunt viroid (HSVd; Pospiviroidae, Hostuviroid) and grapevine yellow speckle viroid 1 (GYSVd-1; Pospiviroidae, Apscaviroid), common in grapevines were previously found in wine grapes (Thompson et al. 2019) but neither GYSVd-2 nor AGVd were identified in the same high-throughput sequencing (HTS) outputs. In September 2020, 16 leaf and petiole samples were collected from six vineyards in Canyon and Nez Perce counties of Idaho, representing six different wine grape cultivars and an unknown table grape cultivar, and subjected to HTS analysis. One of the samples was from a table grape plant at the edge of a declining 'Chardonnay' wine grape block that was grown next to a wine tasting room deck for aesthetic, ornamental purposes; the table grape and 'Chardonnay' plants were own-rooted and planted in 1981. Ribodepleted total RNAs prepared from these samples, as described previously, were subjected to a HTS analysis on a NovaSeq platform (Dahan et al. 2023), producing 15,095,042 to 31,500,611 250-bp paired-end reads per sample. Raw reads were adapter and quality cleaned and mapped against the V. vinifera, reference genome. Unmapped paired-end reads were assembled, and contigs were analyzed using BLASTn and DIAMOND (Buchfink et al. 2021) programs. Fifteen samples were found infected with HSVd and with GYSVd-1, while one was infected with GYSVd-2 and AGVd; in particular, the table grape plant (arbitrarily designated RBTG) was found infected with all four viroid species. The HTS-derived, 490-nt GYSVd-2-specific contig from the table grape sample represented ∼1.35 genome of the Idaho isolate of GYSVd-2 (GYSVd-2-RBTG) and was 100% identical to the GYSVd-2 sequence JQ686716 from Iran. The HTS-derived, 488-nt AGVd-specific contig represented ∼1.32 genome of the Idaho isolate of AGVd (AGVd-RBTG) and was 100% identical to the AGVd sequence KF876037 from Iran. To validate the HTS data and confirm the presence of the four viroids in the original 16 samples, all of them were subjected to RT-PCR using the viroid-specific primers described by Gambino et al. (2014); all 16 samples were found positive for HSVd and GYSVd-1, and one found positive for AGVd. The RBTG sample was confirmed to be infected with HSVd, GYSVd-1, and AGVd by RT-PCR. GYSVd-2 sequence was not amplified, although primers designed by Gambino et al. (2014) matched the HTS-derived GYSVd-2-RBTG sequence; this may be related to a lower concentration of this viroid in the sample and to properties of the primers. The sampled table grape plant was asymptomatic; all four viroids were apparently not associated with any visible abnormalities in this table grape plant, consistent with the findings that viroids found in grapevines typically do not seem to be associated with visible diseases (Habili 2017).

Advancements in deep learning for accurate classification of grape leaves and diagnosis of grape diseases

AbstractPlant diseases cause significant agricultural losses, demanding accurate detection methods. Traditional approaches relying on expert knowledge may be biased, but advancements in computing, particularly deep learning, offer non-experts effective tools. This study focuses on fine-tuning cutting-edge pre-trained CNN and vision transformer models to classify grape leaves and diagnose grape leaf diseases through digital images. Our research examined a PlantVillage dataset, which comprises 4062 leaf images distributed across four categories. Additionally, we utilized the Grapevine dataset, consisting of 500 leaf images. This dataset is organized into five distinct groups, with each group containing 100 images corresponding to one of the five grape types. The PlantVillage dataset focuses on four classes related to grape diseases, namely Black Rot, Leaf Blight, Healthy, and Esca leaves. On the other hand, the Grapevine dataset includes five classes for leaf recognition, specifically Ak, Alaidris, Buzgulu, Dimnit, and Nazli. In experiments with 14 CNN and 17 vision transformer models, deep learning demonstrated high accuracy in distinguishing grape diseases and recognizing leaves. Notably, four models achieved 100% accuracy on PlantVillage and Grapevine datasets, with Swinv2-Base standing out. This approach holds promise for enhancing crop productivity through early disease detection and providing insights into grape variety characterization in agriculture.

Fungal diseases of Betel vine (Piper betle L.) in India and their management : An overview

Fungal diseases of Betel vine (Piper betle L.) in India and their management : An overview