Strawberry Disease Research Articles

Monitoring of harmful objects of strawberry in the conditions of Central Yakutia

This article provides monitoring of pests and diseases of strawberries in the conditions of Central Yakutia for the period since 2010. The research results were obtained on the basis of the Yakut Scientific Research Institute of Agriculture named after M.G. Safronov. The studies of harmful objects are based on standard methods for their determination. During the research since 2010, it has been established that strawberry leaf beetle, weevil, dead beetle, wireworm, slugs and leafhoppers are classified as less dangerous pests, the damage to which is not significant and depends on weather conditions. In recent years, due to the anthropogenic nature of the territories, birds of the thrush family have been identified as malicious pests of strawberries, which cause irreparable damage to the crop. For bird control, we recommend using mosquito nets, which can largely save the crop. In view of the use of strawberries for the nutrition of the population, over a long period of research (2010-2020), we have identified a biologically proven method of combating diseases and pests using timely treatments with onion peel infusion throughout the growing season, which are effective in combating pests and allows you not to use toxic chemicals, keeping strawberry plantings in an environmentally safe state. An effective way to prevent damage to strawberry leaves by spotting has been revealed - regular treatments with phytosporin. These developments in the culture of strawberries in the conditions of Yakutia make it possible to grow environmentally friendly products for the population.

Identification of Silencing Suppressor Protein Encoded by Strawberry Mottle Virus.

Strawberry mottle virus (SMoV) is associated with strawberry decline disease, causing losses to fruit yield and quality. In this study, using a screening system that enables detection of both local and systemic plant host (RNA silencing) defense responses, we found that Pro2Glu and P28, encoded by SMoV RNA2 genome, functioned to suppress local and systemic RNA silencing triggered by single- but not double-stranded GFP RNA. Subcellular localization assay revealed that both Pro2Glu and P28 were localized to nucleus and cytoplasm. The deletion of 11 amino acid residues at the C-terminus destabilized Pro2Glu protein, and the disruption of two conserved GW motifs deprived Pro2Glu of ability to suppress RNA silencing. Additionally, SMoV Pro2Glu and P28 enhanced the accumulation of potato virus X (PVX) in Nicotiana benthamiana 22 days post-infiltration, and P28 exacerbated significantly the symptoms of PVX. Collectively, these data indicate that the genome of SMoV RNA2 encodes two suppressors of RNA silencing. This is the first identification of a stramovirus suppressor of RNA silencing.

Genetic Diversity and Population Structure of Fusarium commune Causing Strawberry Root Rot in Southcentral China

Strawberry plants and fruits are vulnerable to infections by a broad range of pathogens and pests. However, knowledge about the epidemiology of pathogens causing strawberry diseases is limited. In this study, we analyzed Fusarium commune, a major fungal pathogen causing strawberry root rot, from diseased strawberry root tissues in southcentral China. A total of 354 isolates were obtained from 11 locations that spanned about 700 km from both south to north and east to west. Multilocus genotypes of all isolates were obtained using seven polymorphic simple sequence repeat markers developed in this study. Our analyses revealed significant genetic diversity within each of the 11 local populations of F. commune. STRUCTURE analysis revealed that the optimal number of genetic populations for the 354 strains was two, with most local geographic populations containing isolates in both genetic clusters. Interestingly, many isolates showed allelic ancestry to both genetic clusters, consistent with recent hybridization between the two genetic clusters. In addition, though alleles and genotypes were frequently shared among local populations, statistically significant genetic differentiations were found among the local populations. However, the observed F. commune population genetic distances were not correlated with geographic distances. Together, our analyses suggest that populations of F. commune causing strawberry root rot are likely endemic to southcentral China, with each local population containing shared and unique genetic elements. Though the observed gene flow among geographic regions was relatively low, human activities will likely accelerate pathogen dispersals, resulting in the generation of new genotypes through mating and recombination.

Phenotypic Variability and Genetic Diversity of the Pathogenic Fungus Macrophomina phaseolina from Several Hosts and Host Specialization in Strawberry.

Macrophomina phaseolina, is a pathogenic soil-borne fungus that affects more than 500 plant species, causing various types of disease to several crops, among which is the crown and root rot disease in strawberry. Its wide variability has been characterized reiteratively in the literature, but little is known about its virulence mechanisms. Morphological, physiological, genetic and phytopathogenic parameters were evaluated among 32 isolates of Macrophomina from different hosts occurring in Argentina and Spain. Colony characteristics, average size of microsclerotia, chlorate phenotype and mycelial growth at different temperatures (5º-40°C), and pH (3.0-8.0) were recorded. The morphological and physiological traits were heterogeneous and did not show any association with the genetic structure nor with their pathogenicity. Most of the isolates (71.9%) exhibited chlorate-sensitive phenotype. The optimal growth temperature range was between 25°C and 35°C, and the optimal pH varied between 4.0 and 6.0. The genetic structure analyzed with four DNA markers (EF-1α, ITS, CAL and TUB) showed little diversity among isolates of M. phaseolina, with no clear association with the country of origin, but a significant association with the host. Based on their phylogenetic affinity, one isolate was reclassified as M. pseudophaseolina and another one as M. tecta. It is the first report of M. pseudophaseolina causing charcoal rot on beans, in Argentina, and the first report of M. tecta outside Australia. Pathogenicity tests on strawberry plants revealed marked host specialization, being the isolates obtained from strawberry more virulent than those from other hosts.

Antifungal effects of volatile compounds produced by Tetrapisispora sp. strain 111A-NL1 as a new biocontrol agent on the strawberry grey mold disease.

An antagonistic yeast strain was isolated from the strawberry fruit cv. Paros, and its antifungal properties against Botrytis cinerea causal agent of strawberry grey mold disease were evaluated under in vitro and in vivo experiments. The isolate was tentatively identified as Tetrapisispora sp. strain 111A-NL1 based on phenotypic characteristics and sequence analysis of D1/D2 domains of the 26S rRNA gene. Volatile organic compounds (VOCs) produced by the 111A-NL1 strain inhibited the mycelial growth of fungal pathogen (75.19%) and conidial germination (63.34%); however, inhibition percentage of mycelial growth of pathogen by dual culture test was less (19.49%). Also, the strain produced pectinase, siderophore, chitinase, IAA, as well as gibberellin, and could solubilize phosphate. Additionally, the disease severity of strawberry grey mold was decreased by employing living cells and volatile metabolites methods by 47.61% and 74.05%, respectively, in comparison with untreated control seven days after inoculation. Therefore, its mode of action might consist of antibiosis and VOCs production by yeast strain 111A-NL1 against B. cinerea. The VOCs released by strain 111A-NL1 were analyzed, and thirty-three chemical compounds were determined by gas chromatography-mass spectroscopy (GC-MS). Out of them, Decane (12.79%), Squalene (9.60%), Undecane (7.98%), Benzene, 1,2,3-trimethyl- (7.67%), Nonane, 2,6-dimethyl- (5.69%), Benzene, 1-ethyl-3-methyl- (5.55%), Mesitylene (4.17%), and Phenylethyl Alcohol (3.33%) were the major components. In addition, the selected strain reduced natural decay incidence and weight loss of fruit, and preserved quality parameters of strawberry fruit including firmness, soluble solids content, and titratable acidity. This research averred, for the first time, that the creation of VOCs by Tetrapisispora sp. strain 111A-NL1 could play an essential role as a biofumigant in the antifungal activity against strawberry grey mold.

Native bacteria for field biocontrol of black root rot in Egyptian strawberry

BackgroundIncreasing cultivation of strawberry in Egypt has boosted efforts to increase its yield. Biocontrol agents (BCAs) may avoid side effects and health risks caused by chemical fungicides used to control black root rot disease in strawberry. Some BCAs control the disease and augment strawberry yield, but additional research is needed to fit BCAs into emerging control strategies. The impact of six bacterial isolates of Paenibacillus polymyxa and Bacillus brevis on this disease and on berry yield is reported and compared to a common chemical fungicide.ResultsThe bacterial isolates reduced the growth of the black root rot causal agents Fusarium solani, Rhizoctonia solani, and Macrophomina phaseolina, in dual culture bioassays. The greatest fungal inhibition was caused by P. polymyxa isolates 1 and 2 and B. brevis isolate 2. They suppressed the growth of F. solani, R. solani, and M. phaseolina by more than 74, 76, and 79%, respectively. Disease severity and incidence were significantly reduced on naturally infected strawberry plants in the field by the six isolates. The best results were obtained by the superior bioassay isolates which suppressed the disease incidence by 73, 77, and 71%, and its severity by 72, 78, and 70%, respectively. Disease suppression by bacteria was comparable to that by fungicide Actamyl. Bacteria surpassed Actamyl with regard to strawberry yield and enhancement of peroxidase and chitinase activities in the leaves.ConclusionsThese isolates are potential benign alternatives to fungicides used against black root rot in strawberry in Egypt. More studies are needed to examine their economic use on a wider scale.

Oomycetes associated with strawberry diseases in Corrientes, Argentina

Oomycetes species are widely distributed and represent a significant threat to horticulture, forestry and agriculture. Several factors, such as initial health condition of the plants, date of transplant, environmental conditions and crop management practices contribute to the incidence of these pathogens, leading to important economic losses. Despite the importance of the diseases caused by Oomycetes in vegetable crops in Corrientes (Argentina), there is a serious lack of information about host-pathogen interaction, which makes it difficult to establish efficient control strategies. The objective of this work was to characterize and identify pathogenic oomycetes of strawberry crown and roots in Corrientes. A total of 7 isolates were obtained after field sampling. Morphological and molecular characterization was carried out as well as pathogenicity tests. Five different species of oomycetes were identified: Pythium irregulare, Pythium spinosum, Phytophthora cactorum, Phytopythium vexans and Phytopythium mercuriale. To our knowledge, this is the first record of Pythium irregulare, Phytopythium mercuriale and P. vexans in strawberry in Argentina.

First Report of Botrytis cinerea Causing Leaf Spot on Strawberry in Florida.

During the 2020-2021 Florida strawberry season (October to April), strawberry (Fragaria × ananassa) plants showing leaf spots were observed on samples submitted to the Diagnostic Clinic at the University of Florida's Gulf Coast Research and Education Center. Disease incidence was up to 5% and observed on four different farms in Plant City, FL on cultivars SensationTM Florida127 and Florida Brilliance. All the samples were submitted early in the season (November) and shared the same nursery source in California. Symptoms consisted of circular or irregular lesions with purple or brown halos, eventually developing leaf blight with sporulation at the center on advanced lesions. Diseased tissues (0.5 mm2) were surface disinfested with 10% bleach solution for 90 s, rinsed twice in sterile deionized water, and plated on general isolation medium (Amiri et al. 2018). Plates were incubated at 25°C and a 12-h photoperiod. A fungus producing white mycelia with sparse sporulation of Botrytis-like spores was consistently isolated. Isolates were single-spored and grown on HA medium to induce sporulation (Leroch et al. 2013). Three isolates (20-291, 20-293, and 20-295) were selected for identification and pathogenicity assays. Resulting cultures on HA had profuse sporulation resembling gray mold. Conidia (n=50) were round to ellipsoid ranging from 9 to 14.6 μm long (Avg=10.8, SD=1.3) and 6.3 to 9.5 μm wide (Avg=7.7, Sd=0.7). No sclerotia formation was observed on GI and HA medium. Based on morphology, the pathogen was tentatively identified as Botrytis cinerea (Hong et al. 2001; Jarvis 1977). DNA was extracted from the same three isolates using the FastDNA kit (MP Biomedicals, Solon, OH), and the heat shock protein (HSP60), RNA polymerase II-binding (RPB2), and glyceraldehyde 3-phosphate dehydrogenase (G3PDH) genes were amplified (Staats et al. 2004). Sequences were deposited in GenBank (accession nos. MZ288746 - MZ288754). BLASTn searches revealed that isolates were 100% identical to B. cinerea reported causing leaf spot on strawberry in California; accession numbers MK919494 (HSP60, 996/996 bp), MK919495 (RPB2, 1131/1131 bp), and MK919496 (G3PDH, 877/877 bp). To test for pathogenicity, four one-month-old plants of 'Florida Brilliance' were used per isolate and control treatment. Spores were harvested from two-week-old cultures grown on HA medium, and the suspension adjusted to 106 spores/mL in a solution of 0.1% of Tween 20. Plants were spray inoculated until run-off and kept inside clear plastic boxes for 48 h. Control plants were sprayed with sterile deionized water. Afterward, plants were kept in a misting table in the greenhouse with a water regime of 3 s every 10 min during the day. Disease incidence was evaluated weekly, and the experiment repeated once. Two weeks after inoculation, leaf spots were observed in all inoculated plants, while controls remained healthy. Fungi morphologically identical to the original isolates were re-isolated from the diseased tissues. To our knowledge, this is the first report of B. cinerea causing leaf spot on strawberry in Florida. This disease was recently reported in California (Mansouripour and Holmes 2020), which is where the transplants originated from. Considering the disease was observed early in the Florida season, it is likely that it was introduced with transplants from the nursery. This pathogen is also the causal agent of Botrytis fruit rot, which is considered a major disease of strawberry, and a previous study has shown that populations resistant to multiple fungicides are introduced with transplants (Mertely et al. 2018, Oliveira et al. 2018). While Botrytis leaf spot is currently considered rare and of minor significance (Mansouripour and Holmes 2020), it could contribute to the spread of fungicide resistance to from nursery to strawberry fruit production fields. Efforts should be implemented to monitor its occurrence and spread considering the high variability and fungicide resistance profile of this pathogen.

A Hyperspectral Data 3D Convolutional Neural Network Classification Model for Diagnosis of Gray Mold Disease in Strawberry Leaves.

Gray mold disease is one of the most frequently occurring diseases in strawberries. Given that it spreads rapidly, rapid countermeasures are necessary through the development of early diagnosis technology. In this study, hyperspectral images of strawberry leaves that were inoculated with gray mold fungus to cause disease were taken; these images were classified into healthy and infected areas as seen by the naked eye. The areas where the infection spread after time elapsed were classified as the asymptomatic class. Square regions of interest (ROIs) with a dimensionality of 16 × 16 × 150 were acquired as training data, including infected, asymptomatic, and healthy areas. Then, 2D and 3D data were used in the development of a convolutional neural network (CNN) classification model. An effective wavelength analysis was performed before the development of the CNN model. Further, the classification model that was developed with 2D training data showed a classification accuracy of 0.74, while the model that used 3D data acquired an accuracy of 0.84; this indicated that the 3D data produced slightly better performance. When performing classification between healthy and asymptomatic areas for developing early diagnosis technology, the two CNN models showed a classification accuracy of 0.73 with regards to the asymptomatic ones. To increase accuracy in classifying asymptomatic areas, a model was developed by smoothing the spectrum data and expanding the first and second derivatives; the results showed that it was possible to increase the asymptomatic classification accuracy to 0.77 and reduce the misclassification of asymptomatic areas as healthy areas. Based on these results, it is concluded that the proposed 3D CNN classification model can be used as an early diagnosis sensor of gray mold diseases since it produces immediate on-site analysis results of hyperspectral images of leaves.

Molecular screening of the VIR strawberry varieties collection for the presence of a marker for the anthracnose black rot resistance gene <i>Rca2</i>

Background. Anthracnose black rot caused by the phytopathogenic fungus Colletotrichum acutatum Simmonds became an extremely harmful disease of strawberries in Southern Russia. The disease is widespread throughout the world, and relatively recently it appeared in Russia. Yield losses due to the disease reach up to 80%; besides, the pathogen causes significant plant losses in mother plantations. The most reliable protection against the pathogen is the cultivation of resistant varieties. In strawberries, resistance is controlled by different genes, including Rca2. To identify this gene, molecular markers STS_Rca2_240 and STS-Rca2_417 have been developed. The purpose of this study was to use the markers for screening the VIR collection of strawberry varieties at the VIR Maikop Experiment Station (Maikop ES VIR). Material and methods. The present work studied 135 varieties of Fragaria × ananassa (Duchesne ex Weston) Duchesne ex Rozier, 83 domestic and 52 foreign ones. The domestic varieties included 17 created at the Maikop ES. Plants were evaluated for anthracnose field resistance in the Republic of Adygea from 2018 to 2021. Molecular screening was performed using STS_Rca2_240 and STS-Rca2_417, the molecular markers closely linked to the Rca2 gene. Microsatellite primers EMFv020 were used to control the PCR. The cultivar ‘Sudarushka’, in which the presence of STS_Rca2_240 marker was described in the literature, served as a positive control. Results and discussion. The marker Rca2_240 was detected in 22 cultivars from 135 studied. Among domestic varieties, the frequency of the marker was 18.1%, while among the foreign varieties it was slightly lower and amounted to 13.0%. Among the 17 varieties created at the Maykop SE, the marker was found in three: ‘Majkopskaya rannyaya’, ‘Peryt’, and ‘Shapsugskaya’. The association of the diagnostic fragment with resistance was 73.0%. The marker efficiency was not very high due to the significant number of resistant varieties which do not generate the diagnostic fragments. The resistance in such varieties can be provided by other genes, for example, FaRCa1. The STS-Rca2_417 marker was not effective during screening. Conclusion. Twenty-two varieties with the STS_Rca2_240 marker were identified in the VIR collection, maintained at the Maykop ES VIR, 16 of which were resistant to C. acutatum. These varieties represent a valuable breeding material. The STS-Rca2_240 marker can be used as an important diagnostic trait for the certification of varieties.

Research on Strawberry Disease Diagnosis Based on Improved Residual Network Recognition Model

Considering the problems of high cost, inefficiency, and time consumption of manual diagnosis of strawberry diseases, G-ResNet50 is proposed based on transfer learning and deep residual network for strawberry disease identification and classification. The G-ResNet50 is based on the ResNet50, and the focal loss function is introduced in G-ResNet50 to make the model devote itself to disease images that are difficult to classify. During the training process of the G-ResNet50 model, its convolutional layer and pooling layer inherit the pre-trained weight parameters from the ResNet50 model on the PlantVillage dataset, while adding dropout regularization and batch regularization methods to optimize the network model. The strawberry disease dataset includes four sample images of healthy plants, powdery mildew, strawberry anthracnose, and leaf spot disease. The dataset is enhanced and expanded by operations including angle rotation, adjusting contrast and brightness, and adding Gaussian noise. Compared with existing models such as VGG16, ResNet50, InceptionV3, and MobileNetV2, the results of model training and testing on 7,525 four-category leaf datasets show that the G-ResNet50 model has faster convergence speed and better classification effect, and its average recognition accuracy rate reached 98.67%, which is significantly higher than other models. Through the three evaluation indicators of precision rate, recall rate, and confusion matrix, it is concluded that the G-ResNet50 has good robustness, high stability, and high recognition accuracy and can provide a feasible solution for strawberry disease detection in practical applications.

First Report of Neopestalotiopsis mesopotamica Causing Root and Crown Rot on Strawberry in Ecuador.

In Ecuador, strawberry production is located in the Andean region with an area of 1000 ha. Albion is the most popular cultivar due to its conical fruit shape, fruit size, bright red color, and sweetness. Since June 2014, farmers reported a reduction in the production cycle from 24 months to 6-8 months and a decreased yield of around 50% due to an unknown soil pathogen. Plant symptoms presented a reddish discoloration on new leaves, coming through the leaf apex to the petiole until turning wholly brown in old leaves leading to plant death. Additionaly, a brown-reddish spot inside the strawberry crown and root rot were reported (Fig. S1). In 2020, in Ecuador's most extensive production area, called Yaruqui (Pichincha province), 25 diseased plants were collected for pathogen isolation. The pathogen was isolated on water agar medium from the crowns internal tissue using 0.5 cm diseased plant fragments, previously disinfected with 2% sodium hypochlorite, and rinsed with sterile water. After two days, single hyphal tip was reisolated on potato dextro agar (PDA). A total of 18 pure isolates were grown at 25°C for 12 days, then 3-7 days of blacklight treatment was applied to induce sporulation. All the isolates presented a cottony beige mycelium with undulate edges. The conidia were ellipsoidal (range between 20.73 to 29 µm in length and 6.2 to 8.77 µm in width; n=60), multiseptated (4 segments) showing hyaline apical (3.8 to 5 µm) and basal (4.87 to 8 µm) cells, and three brown median cells, the second and third were darker than the fourth one, with one basal and 2 to 4 apical appendages (26.09 to 38.7 µm; Fig. S1). According to colony and conidia morphology, the isolates were identified as Neopestalotiopsis sp. (Dung et al. 2016; Essa et al. 2018; Maharachchikumbura et al. 2011). Five isolates were select randomly for DNA extraction and sequencing of the internal transcribed spacer (ITS) region (ITS4/ITS5), β-tubulin (Bt2b/ T1), and translation elongation factor 1-alpha (TEF-1a) region (EF1-728/ EF1-986) (Maharachchikumbura et al. 2014). DNA sequences obtained from each marker were identical for all isolates. Consensus sequences and alignment were built using ClustalX in MEGA X (Kumar et al. 2018). The consensus sequences were deposited in GenBank with the following accession numbers: ITS, MZ047602; β-tubulin, MZ054301; and TEF-1a, MZ054302. A multilocus Bayesian inference phylogenetic tree was constructed using the concatenated sequences in the Beast software (version 1.8.4)(Drummond et al. 2012; Maharachchikumbura et al. 2014). The isolate in our study clustered with isolates of Neopestalotiopsis mesopotamica with a posterior probability of 1, confirming its identity (Fig. S2). For Koch's postulates, healthy plants were grown in sterile soil for four months. Conidia of the pathogen were suspended in potato dextro broth (PDB) (1 x 104 conidia/ml), and it was sprayed on 15 healthy plants that previously had their crowns wounded with a sterile needle (0.6 cm deep) at the four cardinal points. The control treatment (15 plants) was wounded and sprayed with PDB alone. The plants were maintained at 25°C and more than 85% relative humidity (Sigillo et al. 2020). Twelve days after inoculation, plants showed reddish discoloration on new leaves, and old leaves presented low-level wilt, rusty color, and necrotic petioles. Forty-one days later, 75% of the treated plants had severe wilt or were dead, showing root and crown rot. Control plants presented no symptoms of the disease. Reisolation of the pathogen from the disease crown tissues was done on water agar and PDA as previously described. The isolates presented the exact morphology of pure cultures obtained from field diseased strawberry crowns. The pathogenicity test was performed twice. To our knowledge, this is the first report of Neopestalotiopsis mesopotamica being the causal agent of root and crown rot on strawberries in Ecuador. N. iranensis and N. mesopotamica have been reported as causal agents of strawberries fruit rot and leaf lesions in Iran (Ayoubi and Soleimani, 2016), and N. clavispora was reported to be causing root and crown rot on strawberry plants in Argentina (Obregon et al. 2018). Disease diagnosis contributes to providing strategies against this new disease. Further investigations are needed to find biological/chemical techniques or cultivar resistance to control this pathogen in strawberries in Ecuador.

Control of Fungal Diseases and Fruit Yield Improvement of Strawberry Using Bacillus velezensis CE 100.

Due to the increasing health and environmental risks associated with the use of fungicides in agriculture, alternatives—such as using plant growth-promoting bacteria (PGPB) to suppress phytopathogens—that simultaneously improve plant yield, are important. This study evaluated the biocontrol efficiency of Bacillus velezensis CE100 against Macrophomina phaseolina and Fusarium oxysporum f. sp. fragariae, the respective causal agents for charcoal rot and fusarium wilt diseases in strawberry, and its potential to enhance strawberry growth and fruit production. B. velezensis CE 100 produced fungal cell wall-degrading enzymes, chitinases, and β-1,3-glucanases; and inhibited the mycelial growth of M. phaseolina and F. oxysporum f. sp. fragariae by 64.7% and 55.2%, respectively. The mycelia of both phytopathogenic fungi showed severe swelling and rupturing of the hyphae compared to the smooth, normal growth in the control group. Moreover, B. velezensis CE100 produced up to 2.8 units/mL of indole-3-acetic acid (IAA) during incubation and enhanced root biomass in strawberries. Consequently, B. velezensis CE 100 not only increased the fruit yield of strawberries by controlling the fungal diseases but also through enhancing plant growth. The findings of this study indicate that B. velezensis CE100 could be a safe, ecofriendly biocontrol alternative to chemical fungicides in strawberry production.

Strawberry crinkle virus (crinkle disease of strawberry)

Strawberry crinkle virus (crinkle disease of strawberry)

Strawberry crinkle virus (crinkle disease of strawberry)

This datasheet on Strawberry crinkle virus covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Vectors & Intermediate Hosts, Diagnosis, Biology & Ecology, Impacts, Prevention/Control, Further Information.

A rapid, low-cost deep learning system to classify strawberry disease based on cloud service

Accurate and timely classification of diseases during strawberry planting can help growers deal with them in timely manner, thereby reducing losses. However, the classification of strawberry diseases in real planting environments is facing severe challenges, including complex planting environments, multiple disease categories with small differences, and so on. Although recent mobile vision technology based deep learning has achieved some success in overcoming the above problems, a key problem is how to construct a non-destructive, fast and convenient method to improve the efficiency of strawberry disease identification for the multi-region, multi-space and multi-time classification requirements. We develop and evaluate a rapid, low-cost system for classifying diseases in strawberry cultivation. This involves designing an easy-to-use cloud-based strawberry disease identification system, combined with our novel self-supervised multi-network fusion classification model, which consists of a Location network, a Feedback network and a Classification network to identify the categories of common strawberry diseases. With the help of a novel self-supervision mechanism, the model can effectively identify diseased regions of strawberry disease images without the need for annotations such as bounding boxes. Using accuracy, precision, recall and F1 to evaluate the classification effect, the results of the test set are 92.48, 90.68, 86.32 and 88.45%, respectively. Compared with popular Convolutional Neural Networks (CNN) and five other methods, our network achieves better disease classification effect. Currently, the client (mini program) has been released on the WeChat platform. The mini program has perfect classification effect in the actual test, which verifies the feasibility and effectiveness of the system, and can provide a reference for the intelligent research and application of strawberry disease identification.

Integrating management of powdery mildew with Botrytis in protected strawberries in the UK

Powdery mildew, caused by Podosphaera aphanis, is an important disease of strawberries under protection. Botrytis fruit rot is an important cause of losses in strawberries particularly under open-field conditions. Current control of both these diseases in the UK is dependent on conventional fungicides. Recently, research in the UK demonstrated that integrating biopesticides and biostimulants with a decision-based management programme could achieve reductions in conventional fungicide use without loss in yield or fruit quality. Further field studies were conducted to extend the decision-based management programme to include control of Botrytis fruit rot on everbearer crops. In 2018, three management programmes were compared to a routine fungicide-based programme and an untreated control. In two management programmes, treatments for Botrytis and powdery mildew were either applied routinely or managed. In the third programme, treatments for both diseases were managed. Disease risks were estimated with a simple lookup table based on past and forecast weather. The results showed that the integrated management for both diseases resulted in a nearly 45% reduction in conventional fungicide use and a cost saving of £699/ha compared to a routine programme with no penalties in yield, fruit quality or disease control. There were no significant effects of treatments on Botrytis rot incidence compared to the untreated control, suggesting that the fungicides applied for controlling Botrytis gave no benefit. In 2019, two treatments based on the decision-based management system for powdery mildew and Botrytis, one of which excluded specific fungicide treatment for Botrytis, were compared to an untreated control and a routine fungicide programme. Cool chain management of the fruit post-harvest was also included to extend post-harvest fruit shelf life. The results showed that the simple decision-based system for determining treatments for mildew and Botrytis based on biopesticides and omitting Botrytis-specific fungicides resulted in a 93% reduction in fungicide use and a cost saving of £924/ha compared to a routine programme with no penalties in yield, fruit quality or disease control. Cool chain management delayed the development of both Botrytis and soft rots. In both years, detectable fungicide residues were considerably reduced in the fruit from the managed programmes.

Efficacy of botanicals against Pestalotia leaf spots in Strawberry

Pestalotia leaf spot is a serious disease of strawberry in temperate and subtropical areas. In the present study, out of thirteen aqueous botanicals evaluated under in vitro conditions, neem (Azadirachta indica) and Darek (Melia azedarach) were found most effective with 38.26 and 38.10 per cent of mycelial inhibition of Pestalotia followed by Roylea elegans (34.56%) and Ocimum sanctum (33.82%). The mycelial growth inhibition increased with the increase in concentration of plant extract. Among botanicals-based bio-formulations, Neemazal was found most effective with 75.78 per cent mycelial inhibition followed by botanical field formulation-2 (BFF-2) (57.05%) and botanical field formulation-1 (BFF-1) (26.16%). Among botanicals-based bio-formulations, Neemazal and BFF-2 were found most effective with disease incidence of 10.38 and 12.06 per cent and disease index of 4.24 and 6.54 per cent respectively. The yield recorded was 137.45, 141.34 and 138.00 q/ha and number of runners was 36.0, 37.6 and 35.8 in BFF-1, BFF-2 and Nemazal treatments respectively which were higher than control (53.68 q/ha and 13.8 respectively) but there were no differences among BFF-1, BFF-2 and Nemazal for these traits. Highest average plant height of 39.34 cm was recorded in the treatment BFF-2 followed by BFF-1 and Neemazal with plant height of 37.86 and 36.72 cm respectively, the latter two being at par. Thus foliar sprays of cow urine-based botanical field formulation (BFF-2) at 10 days interval starting from first week of July were found effective and may be recommended for management of disease under field conditions.

Quantitative assessment of white spot (Ramularia tulasnei) disease severity of strawberry based on hyperspectral imaging

This study examined strawberry white spot disease severity using different hyperspectral imaging analyzing methods. The plant leaf images were classified by spectral angle mapper (SAM), by vegetation indices (RENDVI, GNDVI, MCARI) thresholds and by principal component analysis (PCA) method. The SAM method showed the overall accuracy 84% when classifying three types of visual symptoms of the disease.

Management of strawberry gray mold disease using some essential oils and molecular identification of pathogen fungus

Background Evaluation of preharvest application with some essential oils (EOs) for controlling gray mold disease of strawberry plants was studied.Objective In vitro trails, five EOs, that is, thyme, nerol, citral, methyl anthranilate, and clove oils, were evaluated for their capability to suppress fungal growth of Botrytis cinerea. At the National Center for Biotechnology Information, alignment showed the percentage of identity (100%) of B. cinerea between our isolates and Gene bank isolate.Materials and methods Five EOs were evaluated for their capability to suppress fungal linear growth of B. cinerea. Certain volume of each oil was added to autoclaved potato dextrose agar medium flasks to obtain the proposed concentrations of 00.0, 0.25, 0.5, and 1.0% with 0.1% Tween-80. Molecular identification using the internal transcribed spacer (ITS) region of rRNA Trimmed sequences (ITS 573 bp) was conducted.Results and conclusion B. cinerea isolate no. 3 was identified molecular using the ITS region of rRNA Trimmed sequences (ITS 573 bp) compared with different isolates of B. cinerea. All tested oils significantly reduced linear growth of B. cinerea fungus. Complete inhibition was obtained with concentration of 1.0% with all tested EOs and at 0.5% with thyme, citral, and methyl anthranilate, whereas concentration 0.25% showed moderate effect. Moreover, in vivo trails all tested EOs treatments at concentration of 0.5% significantly reduced disease incidence under natural infection. The most effective treatments are citral, methyl anthranilate, and thyme that reduced the disease incidence by 64.3%, 67.9%, and 67.9% on average at 5°C and 75.8%, 82.3%, and77.4% on average at 20°C, respectively, whereas other treatments showed moderate effect. The same trend was observed with disease severity. Meanwhile, under artificial infection, the highest reduction was obtained with citral, methyl anthranilate, and thyme that reduced the disease incidence by 68.2%, 75.0%, and 68.0% at 5°C and 76.0%, 77.0%, and 78.0% on average at 20°C, respectively. However, other treatments showed moderate effect. The same trend was observed with disease severity. As for fruit quality, all tested treatment had no negative effect on all tested characters of fruit quality. The most effective treatments are citral, methyl anthranilate, and thyme that reduced the decay incidence by 71.0%, 71.0%, and 69.3% and weight loss percentage by 79.4%, 78.2%, and 78.8%, respectively. Also, other treatments showed moderate effect, whereas methyl anthranilate, followed by thyme and clove increased the total soluble solid by 56.9%, 41.4%, and 36.2%, respectively. As for total soluble phenol, the highest increase was obtained with all tested oils. As for, titratable acidity, there are no significant differences between all tested treatments as compared with control fruits.