A review of the most common and economically important diseases that undermine the cultivation of tomato crop in the mediterranean basin

Tomato (Solanum lycopersicum L.), family Solanaceae, has become in the past fifty years one of the most important and extensively grown horticultural crops in the Mediterranean region and throughout the world. In 2019, more than 180 million tonnes of tomato have been produced worldwide, out of which around 42 million tonnes in Mediterranean countries. Due to its genetic properties, tomato is afflicted by numerous plant diseases induced by fungal, bacterial, phytoplasma, virus, and viroid pathogens. Not only is its genetic inheritance of great importance to the management of the numerous tomato pathogens, but equally as important are also the present climate changes, the recently revised phytopathological control measures, and the globalization of the seed industry. Thus, the recognition of symptoms and the knowledge of the distribution and spread of the disease and of the methods for early detection of the pathogens are the major prerequisites for a successful management of the disease. In this review, we will describe the main tomato pathogens in the Mediterranean area that impact mostly the tomato yield and provide the current and perspective measures necessary for their successful management

Characterization of \u3ci\u3eBotrytis cinerea\u3c/i\u3e from Commercial Cut Flower Roses and Evaluation of Current Crop Management Practices

Botrytis cinerea Pers. is a necrotrophic fungal pathogen that infects over 235 different plant species around the world. In cut flower roses, B. cinerea causes gray mold disease which leads to large economic losses during greenhouse production and in the post-harvest environment. Disease symptoms are often not visible during the production stage but are observed after storage and/or transportation. Fungicide applications are the primary strategy for gray mold management. However, fungicide resistance has been observed in several crops around the world, resulting in lack fungicide efficacy. Cultural practices such as plant nutrient management, cultivar selection, and crop sanitation are also important aspects of the disease management program. Despite the extensive efforts to control this pathogen, gray mold disease remains a persistent threat for cut rose production. In the first part of this research project, Botrytis cinerea Pers. sensu stricto was confirmed as the unique causal agent of gray mold in cut roses from Colombia. Other pathogenic fungi were identified, e.g., Alternaria alternata, Cladosporium cladosporoides, Epicoccum nigrum, Penicillium citrinum, Aspergillus brasiliensis and Diplodia sp. These fungi may become problematic in the future. Gray mold incidence and severity were evaluated in different rose tissue from the Botrytis susceptible cultivar ‘Orange Crush’. Six commercial shipments from two different greenhouses at the same farm in Colombia were evaluated. The petals showed the highest disease incidence and severity. A total of 49 B. cinerea isolates were collected during the severity and incidence evaluation. Fungicide resistance profiling was performed using ten fungicides. The isolates showed high occurrence of resistance to boscalid, cyprodinil, iprodione and thiophanate-methyl; moderate frequency of resistance to isofetamid, fenhexamid, fluopyram, and penthiopyrad, low resistance to fludioxonil, and no resistance to pidiflumetophen. Variation in the fungicide resistance profiles were observed between greenhouses and shipments. Isolates with simultaneous resistance to different chemical classes were also observed. In the second part of this research project, B. cinerea spore count was recorded using two spore collectors installed in commercial cut flower greenhouses. The relationship between different production activities and conidia count was also evaluated via hierarchical cluster analysis. From the total 26 activities evaluated, 14 of them were related with a high spore count. A higher spore count was observed during the week days compared to the weekend, which coincided with the days with 50.5% more activities in the greenhouse. Possible relationships between spore count and disease incidence were also evaluated; however, no correlation was observed. The results of this research suggest: 1) fungicide resistance management practices should be implemented to improve the effective life of different fungicides and their efficacy against B. cinerea infection, 2) timely removal of plant debris from the production greenhouses may reduce inoculum proliferation, and 3) avoidance of free water in the greenhouse may reduce inoculum dispersal and germination

Molecular fingerprinting of Botrytis cinerea population structure from different hosts

Botrytis cinerea (teleomorph: Botryotinia fuckeliana) causes gray mold disease on vegetable crops in greenhouses. Profound knowledge on pathogen diversity is necessary for efficiently disease management. In this study, forty-two B. cinerea isolates collected from 36 different greenhouses in Antalya province of Turkey were investigated. Twelve SRAP (sequence-related amplified polymorphism) and 18 ISSR (inter simple sequence repeat) primers producing high polymorphic fragments were used to genetic diversity of B. cinerea isolates infecting dill, basil, lettuce, bean, cucumber, tomato, pepper and eggplant. The unweighted pair-group method with arithmetic average analysis (UPGMA) was used to evaluate of combined ISSR and SRAP data showing a similarity range 0.15-0.90 among the isolates. Cophenetic correlation of the tree was high level (r=0.93). Interestingly, cluster analysis showed a divergent group consisting of lettuce isolates which were genetically different from the other isolates. On the other hand, transposable elements (Flipper and Boty) were detected among isolates from all the hosts. Isolates containing only the Fliper element were detected. The results showed that genetically characterized B. cinerea populations by a high level of genetic diversity were associated with genotype flow and the evolutionary potential of B. cinerea. In further studies, the newly tested molecular markers are useful and can be suggested for analyzing of genetic diversity and population structure of this pathogen on different hosts

Integrated and Ecological Crop Protection (I/ECP)

Manual on integrated and ecological crop protectio

Biocontrol of Botrytis cinerea and promotion of tomato growth by local soil-borne Bacillus isolates

Grey mould, which is caused by Botrytis cinerea Pers., is among the most damaging diseases of cultivated plants worldwide. The use of fungicides dominates in the protection of tomatoes against grey mould. Due to the emergence of resistance of pathogens to the active ingredients of fungicides, the possibility of using bacteria of the genus Bacillus was studied. A total of 666 isolates were isolated from different agricultural soils, and a preliminary screening dual culture test with Alternaria dauci was done. A total of 77 isolates were dual culture tested against Fusarium tricinctum and F. proliferatum. Based on preliminary dual culture testing, eight Bacillus isolates were selected for testing their biological potential against two isolates of B. cinerea. The effect of Bacillus spp. isolates was studied for seed germination and plant growth promotion (PGP) on the seedlings of tomato (Solanum lycopersicum L.). Using molecular identification (16S rDNA), five bacterial isolates were identified as Bacillus subtilis, two isolates as B. amyloliquefaciens, and one isolate as B. pumilus. Using the Internal transcribed spacer (ITS) region, two fungal isolates from an infected leaf and a tomato fruit were identified as B. cinerea. The results of the dual culture test showed that eight bacterial isolates could significantly inhibit the growth of B. cinerea mycelia from 50% to 80%. Two isolates B. amyloliquefaciens 28.3 and B. amyloliquefaciens 21/IV increased seed germination by 85.66% and 86.16%, respectively, compared to the control (82.66%). All bacterial isolates positively affected the morphological parameters of the seedlings. In the greenhouse experiment, three isolates B. subtillis 20.10, B. amyloliquefaciens 28.3, and B. amyloliquefaciens 21/IV and their mixture increased all measured PGP parameters. Isolates Bac 20.10 and Bac 28.3 reduced the severity of grey mould disease by 27.47% and 30.36%, respectively. These results show that Bacillus isolates have the potential for biological control of grey mould; also, that they have a positive effect on the growth of tomato plants

Unveiling the Potential of Calcium and Natamycin for Botrytis Blight Management on Cut Roses

Botrytis blight caused by the fungus Botritys cinerea is the most devastating disease of cut roses. The extensive use of fungicides used for Botrytis blight management during cut rose production and postharvest represents a severe threat in terms of fungicide resistance development as has been previously reported. Additionally, health concerns for growers and the environment are growing in recent years making consumers more aware of the fungicides in the products that they consume including ornamentals. This scenario highlights the importance of searching for alternative products to synthetic fungicides. During this research, the use of calcium as an alternative management strategy was evaluated when used as a flower spray during greenhouse production (0, 500, 1000, and 1500 mg.L-1) or as a postharvest treatment (0, 1000, and 2000 mg.L-1, with and without coadjuvant). Additionally, natamycin postharvest dips alone and in combination with coadjuvant and calcium were assessed. Our results show that calcium sprays during production reduced Botrytis blight severity when applied at 500 and 1000 mg.L-1, but these spray applications did not result in an increase in the calcium concentration in the petal tissue. Postharvest calcium dip treatments at 2000 mg.L-1 were effective to decrease botrytis blight severity, increase calcium concentration in the petal tissue, increase the petal tissue to rupture, and were involved in the regulation of metabolic pathways involved in the activation of disease resistance mechanisms. Natamycin dips appear to be effective for several cultivars when applied at 500 mg.L-1.However, the best response was obtained when applied in mixtures with calcium. These two products used alone or in combination can provide an additional tool for an integrated disease management program which at the same time helps implementing effective fungicide resistance management strategies to reduce fungicide resistance development by potentially decreasing the amount of fungicide applications required in the greenhouses and during the postharvest of cut-roses

Nanocapsules of ZnO Nanorods and Geraniol as a Novel Mean for the Effective Control of Botrytis cinerea in Tomato and Cucumber Plants

Inorganic-based nanoparticle formulations of bioactive compounds are a promising nanoscale application that allow agrochemicals to be entrapped and/or encapsulated, enabling gradual and targeted delivery of their active ingredients. In this context, hydrophobic ZnO@OAm nanorods (NRs) were firstly synthesized and characterized via physicochemical techniques and then encapsulated within the biodegradable and biocompatible sodium dodecyl sulfate (SDS), either separately (ZnO NCs) or in combination with geraniol in the effective ratios of 1:1 (ZnOGer1 NCs), 1:2 (ZnOGer2 NCs), and 1:3 (ZnOGer2 NCs), respectively. The mean hydrodynamic size, polydispersity index (PDI), and ζ-potential of the nanocapsules were determined at different pH values. The efficiency of encapsulation (EE, %) and loading capacity (LC, %) of NCs were also determined. Pharmacokinetics of ZnOGer1 NCs and ZnOGer2 NCs showed a sustainable release profile of geraniol over 96 h and a higher stability at 25 ± 0.5 °C rather than at 35 ± 0.5 °C. ZnOGer1 NCs, ZnOGer2 NCs and ZnO NCs were evaluated in vitro against B. cinerea, and EC50 values were calculated at 176 μg/mL, 150 μg/mL, and > 500 μg/mL, respectively. Subsequently, ZnOGer1 NCs and ZnOGer2 NCs were tested by foliar application on B. cinerea-inoculated tomato and cucumber plants, showing a significant reduction of disease severity. The foliar application of both NCs resulted in more effective inhibition of the pathogen in the infected cucumber plants as compared to the treatment with the chemical fungicide Luna Sensation SC. In contrast, tomato plants treated with ZnOGer2 NCs demonstrated a better inhibition of the disease as compared to the treatment with ZnOGer1 NCs and Luna. None of the treatments caused phytotoxic effects. These results support the potential for the use of the specific NCs as plant protection agents against B. cinerea in agriculture as an effective alternative to synthetic fungicides

Biocontrol of fusarium crown and root rot of fresh market tomato with trichoderma harzianum strains under greenhouse conditions

2003 Spring.Covers not scanned.Includes bibliographical references.Greenhouse tomato growers in the United States have few products available for chemical control of plant pathogens. Biological control of soilborne plant pathogens by antagonistic microorganisms is a potential alternative to the use of chemical pesticides during greenhouse production. Biological control experiments were conducted to test the effects of commercial and noncommercial strains of Trichoderma harzianum against Fusarium oxysporum f. sp. radicis-lycopersici on tomato plants grown in two different hydroponic media, coir and rockwool. This study also investigated effects of strains on growth of tomato seedlings under greenhouse conditions. Trichoderma harzianum is a fungus that attacks a range of economically important phytopathogenic fungi. Tomato (Lycopersicon esculentum Mill., cultivar Caruso) plants were inoculated with T. harzianum strains (PlantShield™, T22 and T95) prior to challenge with the pathogen. They were applied to growing media prior to sowing and to roots at transplanting at two inocula densities, 106 or 107 conidia/ml. The results of this study demonstrated that T. harzianum strains, especially applied at transplanting, decreased Fusarium crown and root rot incidence 79% for coir and 73% for rockwool, decreased disease severity 45% for coir and 48% for rockwool, and increased fruit yield 37% for coir and 25% for rockwool on tomato for control. The results also demonstrated that Trichoderma harzianum strains improved tomato seedling growth