Citrus Research Articles

Green Silver Nanoparticles and Their Activity as Antifungal Agents Against Penicillium digitatum Causing Green Mould of Citrus

AbstractThe green synthesis of silver nanoparticles (SNPs) using aqueous extracts of five plants viz., Ocimum americanum, Azadirachta indica, Allium sativum, Eucalyptus hybrida, Zingiber officinale were evaluated for their antifungal property against Penicillium digitatum, a green mould pathogen of citrus fruits. The five plant species were selected from a screening of aqueous extracts from 16 plant species. The efficacy of aqueous extracts, at 50 % concentration, ranged from 14.44–68.52 % inhibition in mycelia growth of P. digitatum. Among SNPs, O. americanum was found most efficacious, at 1000 ppm concentration, with 80.7 % mycelial inhibition followed by A. indica with 77.4 % mycelial growth inhibition of fungal pathogen. Further, physical and structural characterization of SNPs of O. americanum and A. indica was carried out. The characterization analysis executed via transmission and scanning electron microscope revealed size distribution and nanoparticles were spherical to irregularly shaped ranging from 22.8–250 nm in O. americanum and 26.5–500 nm in A. indica. In UV‐visible spectrophotometer, the absolute absorption peak was recorded at 448 nm and 442 nm for O. americanum and A. indica, respectively. FTIR analysis of SNPs of A. indica and O. americanum confirmed the presence of carboxyl, amide group and secondary amines which were the main constituent of proteins. The novelty of the present study is in the green synthesis of silver nanoparticles with potential in the management of postharvest pathogens of fruit crops. The synthesis of SNPs used in this study is simple, environmentally benign and cost‐effective using aqueous extract of native plants.

Citric acid production by Brazilian garlic Aspergillus welwitschiae strains using orange residues

The global production of citrus fruits has expressively grown resulting in large amounts of residue. Orange residues are rich in carbon and could be used as substrates for production of biomolecules such as citric acid. In this study, wild and mutant Aspergillus welwitschiae strains isolated from Brazilian garlic were used to produce citric acid from orange residues, using solid-state fermentation. The results showed that the mutant A. welwitschiae UELAs 15.262/35 produced great amount of citric acid in the fourth day of solid-state fermentation using total and reducing sugars and producing cellulases. On the other hand, there was no production of citric acid by wild A. welwitschiae UELAs 15.262. The use of total and reducing sugars and the production of cellulases by A. welwitschiae UELAs 15.262 were detected, suggesting the use of carbon sources for the production of other metabolites. The great use of reducing sugars and cellulases production by A. welwitschiae UELAs 15.262/35 indicated the consume of carbon sources from the orange residue to produce citric acid at early times of fermentation. These findings lead to the possibility of biotechnological valorization of orange residues for acid organic production by A. welwitschiae strain.

Phytochemistry, Nutritional, and Pharmacological Potential of Citrus Limonum

The current research aimed to provide an overview of the phytochemical configuration, nutritional value, and therapeutic uses of Citrous Limonum (lemon). Its fruit contains a variety of phytochemicals including citric acid, polyphenols, terpenes, limonene, flavonoids, vitamin C, sugar, pectin, citric acid, malic acid, flavonoids, carotenoids, terpineol, fellander, camhenium, citrain, calcium oxalates, and mucilages. Vitamin C is abundant in citrous fruits, as well as macronutrients (dietary fibre and simple sugar) and micronutrients (copper, magnesium, phosphorus, calcium, potassium, pantothenic acid, riboflavin, vit B6 niacin thiamin, and folate). Lemon oil is composed of 70% limonene and 20% monoterpenes, along with significant amounts of aldehydes, such as citral, alcohols (linalool), and esters (coumarin). Lemon peel contains high concentrations of flavonoids, glycosides, coumarins, steroids (beta, gamma, sitosterol), dietary fibers, carbs, and volatile oils, all of which are necessary for good health and appropriate development. However, citrus fruits are low in calories, salts, and cholesterol. They find uses in herbal remedies due to their antioxidant, antifungal, anti-cholesterol, anticancer, antiulcer, antidiabetic, antibacterial, and anti-inflammatory characteristics. It is also important to mention that the excessive use of lemon may also be associated with some risks, such as the lowering of sperm count.

Biocontrol of citrus fungal pathogens by lipopeptides produced by Bacillus velezensis TZ01.

Citrus diseases caused by fungal pathogens drastically decreased the yield and quality of citrus fruits, leading to huge economic losses. Given the threats of chemical pesticides on the environment and human health, biocontrol agents have received considerable attention worldwide as ecofriendly and sustainable alternative to chemical fungicides. In the present study, we isolated a Bacillus velezensis strain TZ01 with potent antagonistic effect against three citrus pathogenic fungi: Diaporthe citri, Colletotrichum gloeosporioides and Alternaria alternata. The culture supernatant of this strain exhibited remarkable antifungal activity on potato dextrose agar plates and detached leaves of five citrus varieties. Treatment with TZ01 culture supernatant obviously affected the hyphal morphology and caused nucleic acid leakage. The crude lipopeptides (LPs) extracted from the culture supernatant were found as the major active ingredients, and could maintain the activity under a wide range of temperature and pH and ultraviolet radiation. Furthermore, the type of LPs, produced in vitro, were explored. Whole-genome sequencing of TZ01 revealed secondary metabolite gene clusters encoding synthetases for non-ribosomal peptides and polyketide production, and gene clusters responsible for the synthesis of three important LPs (surfactin, iturin, and fengycin) were identified in the genome. The liquid chromatography-mass spectrometry analysis confirmed the presence of various homologs of surfactin A, bacillomycin D, and fengycin A in the extracted LPs. Taken together, these results contribute to the possible biocontrol mechanisms of B. velezensis strain TZ01, as well as providing a promising new candidate strain as a biological control agent for controlling citrus fungal pathogens.

Mobile genetic elements of Xylella fastidiosa and their contribution to pathogenicity

AbstractXylella fastidiosa is a destructive bacterial plant pathogen affecting hundreds of plant families, including important crops such as olive and citrus trees and vines. The pathogenicity of this bacterium rests in a group of genes that encode toxins, enzymes, fimbrial/afimbrial adhesins, cell–cell aggregation proteins and other virulence factors. We investigated the contribution of mobile genetic elements (MGEs) to the pathogenicity of X. fastidiosa. Using computational tools, we analysed 94 X. fastidiosa genomes corresponding to the three most important subspecies to identify insertion sequences (ISs) and prophages. Results indicate that the distribution and diversity of ISs are modest, with a few families widespread throughout the subspecies of X. fastidiosa. The prophages are abundant, and play a more significant role in the pathogenicity of X. fastidiosa. Prophages are common in the subspecies of X. fastidiosa and contribute to numerous genes related to pathogenicity. The phylogenetic analyses suggest that prophages are recently acquired and that the rearranging of pathogenicity genes triggered by them could generate strains with new pathogenic capacities. Finally, the contribution of MGEs to the pathogenesis of X. fastidiosa was evidenced by determining their association with virulence genes using a Bayesian framework for phylogenetic analysis of character evolution.

Leaf Nitrogen and Phosphorus Variation and Estimation of Citrus Tree under Two Labor-Saving Cultivation Modes Using Hyperspectral Data

Understanding canopy nitrogen (N) and phosphorus (P) differences is crucial for optimizing plant nutrient distribution and management. This study evaluated leaf N and P content in citrus trees across three cultivation modes: traditional mode (TM), wide-row and narrow-plant mode (WRNPM), and fenced mode (FM). We used hyperspectral data for non-destructive quantification and compared 1080 leaf samples from upper, middle, and lower canopy layers. Four models—Random Forest (RF), Backpropagation Neural Network (BPNN), Partial Least Squares (PLS), and Support Vector Machine (SVM)—were employed for leaf N and P estimation. Results showed that the TM had significantly lower N content compared to the WRNPM and FM, while the WRNPM exhibited higher P content. The canopy layer had minimal impact on N and P in the FM, and leaves in the upper layer had higher nutrient content in the WRNPM and TM. RF provided the best estimation accuracy, with R2 values of 0.66 for N and 0.72 for P. The cultivation mode and canopy layer significantly influenced the estimation accuracy, with the TM yielding the highest R2, followed by the WRNPM and FM obtaining the lowest accuracy. The labor-saving cultivation mode had different nutrient utilization efficiency compared to the TM. The cultivation mode and canopy layer should be considered when hyperspectral data were used for estimating the leaf N and P content. The study can offer new insights for precise fertilization strategies in fruit trees.

Nano-Rutin: A Promising Solution for Alleviating Various Disorders.

Rutin, often known as vitamin P, is a natural flavonoid compound, which offers a broad spectrum of therapeutic potentials. Rutin is metabolised to different compounds by the gut bacteria after consumption, therefore, very little is absorbed. Higher plants contribute to rutin synthesis in large quantities, and it may also be found in many fruits and fruity rinds, particularly citrus fruits and berries. The present paper highlights several studies conducted on rutin along with its nanoformulations regarding its broad spectrum of therapeutic potentials. Numerous electronic databases, including Springer, PubMed, Science Direct, Pubchem, etc. were searched to extract relevant published literature demonstrating rutin effectiveness in various ailments. The reviewed literature showed that rutin and related flavonoids possess a variety of physiological properties that protects human beings, plants and animals. Antioxidant, anti-inflammatory, anti-allergic, cytoprotective, vasoprotective, anticarcinogenic, neuroprotective, cardioprotective, antibacterial, antiviral, antiprotozoal, antitumor, anti-hypertensive antiplatelet, antispasmodic and hypolipidemic, activities. Nanotechnology has been implemented for the improvement of the bioavailability of rutin using novel drug-delivery carriers. The study concludes that the development of rutin nanoformulations for multiple therapeutic approaches contributes towards enhanced aqueous solubility as well as tailored pharmacokinetics compared to conventional delivery of rutin. However, more investigations should be conducted to confirm the improved bioavailability of the rutin nanoformulations.

Innovative Technology of Continuous-Steam Distillation with Packed Column to Obtain Essential Oil-Differentiated Fractions from Mexican Lime (Citrus aurantifolia)

Continuous distillation (CD) by steam is a patented emerging technology that allows us to obtain essential-oil fractions from citrus juices. It presents benefits such as reducing steam consumption by 50%, lowering environmental impact, and, by its design, obtaining fractions enriched in terpenic and oxygenated compounds that can be further processed. The CD of essential oils from Mexican lime juice (Citrus aurantifolia) was studied and the results were compared with conventional steam distillation (batch) in terms of steam consumption, extraction yield, chemical composition, and quality of the essential oils. Different steam flows were used: distillation without a packed column (sc); with packed column (cc); and steam flows of 10, 15, and 20 mL/min with a reflux ratio of 0.5, 1, and 2, respectively. CD was superior in terms of composition, extraction energy savings (0.63 kg steam/kg juice with 1.39 kg steam/kg juice in the conventional), and the extraction yield recovery efficiency was >90%. Gas chromatography-mass spectrometry analysis of the extracted essential oils indicated that the use of CD with a column increases the fractionation of volatile compounds. The result of this study demonstrates that CD can be used as an alternative method to extract the essential oil from lime or any citrus fruit, obtaining differentiated fractions in aroma and composition.

Elemental tracer determination and modeling for geographical origin designation of sweet oranges

Sweet oranges have long been an integral part of global health and culinary practices, offering a wealth of nutrients and bioactive compounds. Ensuring the authenticity of these citrus fruits is essential for maintaining consumer confidence, promoting transparency in sourcing, and protecting producers' reputations in the marketplace. In this study, we explored the feasibility of using multi-element profiling combined with pattern recognition algorithms to trace the origin of sweet orange samples. To achieve this, we employed an optimized microwave plasma atomic emission spectroscopy (MP-AES) method to analyze the elemental composition (Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, and Zn) of 183 orange samples from four production regions in northeastern Argentina. Support vector machine (SVM), random forest (RF), and gradient boosting tree (GBT) models were then built using the collected data to identify elemental tracer's indicative of origin. Based on a comprehensive evaluation of overall accuracy, receiver operating characteristic (ROC) curves, and area under the curve (AUC), the GBT model demonstrated the best classification performance, achieving a 96.5 % correct prediction rate on test samples, as confirmed by the ROC curve (AUC = 0.973). Consequently, this approach provides compelling evidence for the potential utility of MP-AES combined with supervised modeling to determine the geographic origin of sweet oranges produced in Argentina, thereby contributing to consumer protection against fraud.

Post-Harvest Handling through Processing Oranges into Wine to Increase the Added Value of Oranges when Fruit is Abundant and the Skills of the Women Farming Group "Widya Pertiwi" in Belantih Village, Kintamani District, Bangli Regency

The community service activity on aimed at post-harvest handling through processing citrus fruits into wine to increase the added value of citrus fruits when the fruit is abundant. And the skills of the farmer women's group "Widya Pertiwi" in Belantih Village, Kintamani District, Bangli Regency. This service activity is carried out through stages, namely providing material and demonstrations on processing oranges into wine and final evaluation (post-test) through distributing questionnaires. The results of counseling and training showed that through training and hands-on practice, they could easily understand how to process citrus fruit into wine, which could be done when the fruit was excessive in the harvest season, to increase added value and income. The results of this activity showed an overall increase in knowledge where 85% of respondents stated that they understood very well, and the remaining 15% indicated that they understood the extension materials and methods provided, which means that there were no respondents who stated that they did not understand or did not understand. Of the 15 respondents who participated in the counseling, 80% indicated they were very satisfied, and the remaining 20% stated they were satisfied participating in the counseling activities. 95% of the respondents indicated they were very interested, and the remaining 5% stated they were interested in practicing turning citrus fruits into wine in their homes. This means that 100% of the participants from the farmer women's group are interested in improving their skills and applying the technology of processing citrus fruits into wine to reduce the occurrence of fruit spoilage when the fruits are abundant in the harvest season.

Distinctive acidity in citrus fruit is linked to loss of proanthocyanidin biosynthesis

The distinctive acidity of citrus fruit is determined by a regulatory complex of MYB and bHLH transcription factors together with a WDR protein (MBW complex) which operates in the unique juice vesicles of the fruit. We describe a mutation affecting the MYB protein, named Nicole, in sweet orange and identify its target genes that determine hyperacidification, specifically. We propose that the acidity, typical of citrus fruits, was the result of a loss of the ability of Nicole to activate the gene encoding anthocyanidin reductase, an enzyme essential for the synthesis of proanthocyanidins, which are absent in citrus fruit.

Association of Quantity and Diversity of Different Types of Fruit Intake with New-Onset Kidney Stones.

This study aims to assess the association between intake of different types of fruit (citrus, pomes, tropical fruits, berries, gourds, drupes, dried fruits, and other fruits), the intake diversity of fruit types, and risk of new-onset kidney stones in general population. A total of 205896 participants with at least one completed 24-h dietary recall from the UK Biobank are included. During a median follow-up of 11.6 years, 2074 cases of kidney stones are documented. Compared with nonconsumers, participants with higher intake of citrus (50-<100gday-1; hazards ratio [HR] = 0.78; 95% confidence interval [CI], 0.66-0.91; ≥100gday-1; HR = 0.75; 95%CI, 0.63-0.89), pomes (≥100gday-1; HR = 0.86; 95%CI, 0.77-0.96), or tropical fruits (50-<100gday-1; HR = 0.86; 95%CI, 0.75-0.99; ≥100gday-1; HR = 0.88; 95%CI, 0.79-0.99) have a lower risk of new-onset kidney stones. However, there is no significant association of intake of berries, gourds, drupes, dried fruits, and other fruits with kidney stones. A higher fruit variety score is significantly associated with a lower risk of new-onset kidney stones (per 1-score increment, HR = 0.86; 95%CI, 0.81-0.91). Higher intake of citruses (≥50gday-1), pomes (≥100gday-1), and tropical fruits (≥50gday-1), as well as increasing diversity of intake of these three fruits, are associated with a lower risk of new-onset kidney stones.

Comparative Nutritional Analysis of Zest and Pulp in Red and Yellow Grapefruit Varieties

The global cultivation and considerable demand for citrus fruits has given them a prominent place among fruit crops. With them being known for their virtues, health benefits, and characteristic aroma and taste, grapefruits have been accepted as an important food in our diets. Indeed, they play a key role in providing the nutrients to support good health. In this context, we sought to identify the nutritional characteristics of two varieties of grapefruit (citrus paradisi), namely yellow and red. We therefore investigated the water, protein, fiber, total sugar, and fat contents in the zest and pulp of these two species based on international food standards. We also quantified the various saturated and unsaturated fatty acids through gas chromatography. Our results revealed an interesting richness in these grapefruit varieties in terms of factors like total sugar, proteins, and fat, particularly in the peel, as well as a high-water content and energy value. Several fatty acids were also identified, mainly palmitic, oleic, and linoleic acids, which are highly sought after for their therapeutic benefits. This nutrient density highlights the value of these fruits and demonstrates that promoting its consumption can help improve human health and quality of life. This assortment of nutrients found in our samples, as well as the abundance of phenolic compounds already noted in other research studies, highlight this fruit and show the importance of its various parts - peel and pulp - in improving quality of life and human mental and physical health.

Building a physics-based virtual refrigerated container filled with fruit in ventilated packaging

We build a validated physics-based model of a refrigerated container filled with fruit in ventilated packaging. This model of a virtual container is the basis for simulations in an accompanying paper on citrus fruit shipped overseas from South Africa to Europe. The model is used to understand better how the cargo cools and when and where food quality is lost in these supply chains. We build a computational fluid dynamics model with a two-phase porous media approach that simulates the airflow in the container and the cooling process of every fruit. This container can be considered aerodynamically to be a slot-ventilated enclosure. We also model the fruit's thermally-driven quality loss. Using a two-phase porous media approach for the ventilated cargo and modeling temperature-driven fruit quality evolution are two steps forward compared to most existing physics-based refrigerated container models. We validate the porous media model implementation. We define and apply actionable metrics for every fruit inside the cargo, such as remaining shelf life upon arrival and seven-eighths cooling time.• This model can help reduce food loss and increase supply-chain resilience• This model is an essential building block of a refrigerated container's digital twin• This model can support stakeholders in improving cargo temperature control and resulting fruit quality preservation.

Systems Approach to Investigate the Role of Fruit and Vegetable Types on Vascular Function in Pre-Hypertensive Participants: Protocol and Baseline Characteristics of a Randomised Crossover Dietary Intervention.

The evidence on the impact of fruits and vegetable types on cardiovascular risk factors remains limited. Specifically, the utilisation of biomarkers to objectively measure dietary compliance and metabolic responses is emerging. This protocol and baseline characteristics of a pilot randomised controlled, crossover, dietary intervention study aimed to examine the effects of citrus fruits, cruciferous vegetables, or common fruits and vegetables on cardiovascular risk factors. A total of 39 volunteers with untreated prehypertension was recruited and consumed a standardised, provided diet with eight daily portions of citrus fruits and cruciferous vegetables, common fruits and vegetables, or a low fruit and vegetable diet (two portions/d, control diet) in a random order for 2 weeks each, separated by a wash-out week. A targeted cohort-based recruitment strategy was utilised and resulted in 74% of participants recruited by re-contacting preselected individuals from two cohort studies with a 15% average enrolment rate. Participants had an average age of 54.4 years (±6.1 years), BMI of 27.9 kg/m2, and BP of 135/81 mmHg and were mainly male (67%). The primary outcome was office blood pressure; secondary outcomes included arterial stiffness, lipid profiles, inflammation, cognitive function, and subjective mood. Biofluids, i.e., 24 h urine, stool, and blood samples, were collected for biomarker measurements with multiple metabolomic platforms and the gut microbial composition, together with traditional dietary biomarkers.

Effect of Different Forms of Microelements Foliar Application on Vegetative Growth of " Sukkari" Orange Citrus Trees

Effect of Different Forms of Microelements Foliar Application on Vegetative Growth of " Sukkari" Orange Citrus Trees

Penerapan prosedur operasional standar budi daya tanaman jeruk ramah lingkungan untuk menekan infestasi kutu perisai merah Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae)

Jeruk merupakan tanaman hortikultura yang sudah dikembangkan diberbagai daerah di Indonesia. Setiap tahun permintaan buah jeruk selalu meningkat, namun tidak terpenuhi karena produksi rendah. Permasalahan ini disebabkan oleh adanya serangan organisme penggangu tanaman, yaitu hama kutu perisai merah Aonidiella aurantii (Maskel). Upaya yang dilakukan untuk menekan infestasi A. aurantii, yaitu dengan penerapan prosedur operasional standar (SOP) pada budi daya tanaman jeruk ramah lingkungan. Tujuan penelitian ini adalah untuk mengetahui efektifitas penerapan SOP dalam menekan populasi dan intensitas serangan hama kutu perisai merah A. aurantii pada tanaman jeruk. Penelitian dilaksanakan bulan Januari sampai Agutus 2020 di kebun jeruk milik petani di Kota Batu. Penelitian eksperimen ini menggunakan metode teori research design. Perlakuan terdiri atas petak penerapan SOP berupa pemangkasan pemeliharaan, sanitasi kebun, dan aplikasi pupuk organik; dan petak konvensional kebiasaan petani yang tidak melakukan pemangkasan, membersihkan gulma di seluruh kebun, penggunaan pupuk anorganik NKP Mutiara 16-16-16. Luas setiap petak perlakuan adalah 1.500 m2. Pada setiap pelakuan diambil 10 tanaman sampel secara sistematik. Pengamatan setaiap tanaman dilakukan pada ranting atau cabang yang tersebar pada 4 arah mata angin. Pengamatan meliputi jumlah buah terserang, kelimpahan musuh alami, populasi, dan intensitas serangan A. aurantii. Hasil penelitian menunjukkan bahwa perlakuan penerapan SOP budi daya jeruk mampu menurunkan kepadatan populasi dan intensitas serangan hama A. aurantii secara nyata serta mampu meningkatkan kelimpahan musuh alami dan kualitas buah jeruk apabila dibandingkan dengan cara budi daya jeruk pada perlakuan konvensional.

Lemon Juice and Peel Constituents Potently Stabilize Rat Peritoneal Mast Cells.

Lemons (Citrus limon ) contain various nutrients and are among the most popular citrus fruit. Besides their antioxidant, anticancer, antibacterial, and anti-inflammatory properties, clinical studies have indicated their anti-allergic properties. Using the differential-interference contrast (DIC) microscopy, we examined the effects of lemon juice and peel constituents, such as citric acid, ascorbic acid, hesperetin and eriodictyol, on the degranulation from rat peritoneal mast cells. Using fluorescence imaging with a water-soluble dye, Lucifer Yellow, we also examined their effects on the deformation of the plasma membrane. Lemon juice dose-dependently decreased the number of degranulated mast cells. At concentrations equal to or higher than 0.25 mM, citric acid, hesperetin, and eriodictyol significantly reduced the number of degranulating mast cells in a dose-dependent manner, while ascorbic acid required much higher doses to exert significant effects. At 1 mM, citric acid, hesperetin, and eriodictyol almost completely inhibited exocytosis and washed out the Lucifer Yellow trapped on the mast cell surface, while ascorbic acid did not. This study provides in vitro evidence for the first time that lemon constituents, such as citric acid, hesperetin, and eriodictyol, potently exert mast cell-stabilizing properties. These properties are attributable to their inhibitory effects on plasma membrane deformation in degranulating mast cells.

Biocontrol of citrus melanose Diaporthe citri by Bacillus subtilis M23

Citrus melanose, caused by Diaporthe citri, is one of the most prevalent and important fungal diseases of citrus crops globally. However, the overuse of chemical fungicides for disease control has an adverse impact on citrus production. In contrast, biological control agents (BCAs) are environmentally friendly and have become essential tools for plant disease control. In the present study, Bacillus subtilis M23, a strain isolated from healthy citrus leaves, significantly suppressed the mycelial growth of D. citri, the causal agent of citrus melanose, in vitro. The fermentation broth of B. subtilis M23 also exhibited good antifungal activity against D. citri on citrus plants in greenhouse and field experiments. Lipopeptides (LPs) produced by M23 exhibited excellent antifungal activity against D. citri, with a 50 % effective concentration (EC50) of approximately 1.00 and 0.28 μg/mL for inhibition of mycelial growth and conidial germination, respectively. LP biosynthesis genes were identified in the M23 genome using a PCR assay. Notably, LP extracts significantly reduced the formation of pycnidia and ATP biosynthesis in D. citri. Comparative transcriptome analysis revealed significant differences in the expression of genes associated with fungal vacuole, oxidoreductase activity and endopeptidase activity in D. citri treated with B. subtilis M23. Both RNA-seq and RT-qPCR analysis provided similar results on the expression of selected genes. Collectively, our data provided convincing data supporting the biocontrol potential of B. subtilis M23 for the management of citrus melanose.

Optimal management of citrus disease and extreme climatic factors

This study develops a dynamic bioeconomic model using the Bellman equation to derive the optimal management strategy for Witches’ Broom Disease of Lime (WBDL) and the optimal replanting age of citrus trees after the first attack under multiple scenarios of disease management options and climate conditions. In addition, the study investigates different scenarios of disease presence and spread given different climatic conditions of arid, semi-arid and tropical zones in Oman. Factors such as disease incidence, severity, spread, and specific climatic conditions of three growing regions are considered. The farmers' optimal disease mitigation decision is determined by the disease density and insect vector level on the farm, and adverse climate conditions have a significant negative impact on the economic value of citrus cultivation. Results indicate that management measures by citrus growers and policymakers should be based on the climatic conditions of the growing region with a high level of treatment frequency and intensity in the arid region, and lime production should be concentrated in the tropical and semi-arid regions of the country.