Chemical Fungicides Research Articles

Management of Stemphylium Blight Disease Caused by Stemphylium vesicarium in Onion through Different Methodology

A field experiments was conducted at NHRDF, Regional Research Station, Nashik in two consecutive years during rabi 2022-23 and 2023-24 on onion for the management of stemphylium blight disease through different methodology like alteration in transplanting dates, chemical and bio-pesticides management as well as screening of stemphylium tolerant variety. In case of alteration in transplanting dates that the lowest intensity (9.83%) of stemphylium blight and highest yield (391.83 q/ha) was recorded on 3rd week of December. In case of chemical fungicides with bio pesticides the lowest stemphylium blight disease intensity (7.27%) as well as highest yield (399.17 q/ha) was recorded in treatment T4 (Tebuconazole50% + Trifloxystrobin 25% WG @ 0.15% at 45, 60 and 75 DAT while, in case of varietal screening the lowest intensity (10.93%) of stemphylium blight as well as highest gross yield (397.00 q/ha) with marketable (383.83 q/ha) was recorded in variety NHRDF Red-4.

Droplet Digital PCR: A New Molecular Method to Detect G1105S/V Mutations in Plasmopara viticola CesA3 Gene

Plasmopara viticola is the causal agent of Grapevine Downy Mildew (GDM), which is a devastating disease of grapevines in humid temperate regions. The most employed method for protecting grapevines against GDM is the application of chemical fungicides. In Spain, Carboxylic Acid Amides (CAAs) are a fungicide group currently utilized in GDM control. In P. viticola, resistance to CAAs is conferred by G1105S and G1105V mutations in the CesA3 gene. Droplet digital polymerase chain reaction (ddPCR) is an innovative technique that combines PCR and droplet microfluidics to disperse the sample into thousands of water-in-oil droplets in which an amplification reaction is individually performed. In this study, we set up a ddPCR protocol to quantify S1105 and V1105 mutations conferring resistance to CAAs in P. viticola. The optimal PCR conditions were established, and the sensitivity and precision of the protocol were assessed. Four P. viticola populations coming from commercial vineyards in northern Spain were analyzed, and different allele frequencies were found in the analyzed samples corresponding to the different fungicide management strategies, ranging from 7.72% to 100%. Knowing the level of mutated alleles allows for designing resistance management strategies suited for each location. This suggests that similar ddPCR assays could be developed for studying mutations implicated in fungicide resistance in other fungicide groups and plant pathogens.

Reduction of oxidative damage caused by Fusarium falciforme and Fusarium foetens in schefflera plants using chitosan nanoparticles loaded with l-proline or indole butyric acid

Abstract Background Root rot, wilt diseases, and rooting processes have been the major factors that constrain schefflera production. This study focuses on the impact of innovative applications of eco-friendly materials like chitosan nanoparticles loaded with l-proline or indole butyric acid to replace traditional chemical fungicides in controlling root rot and wilt diseases, as well as the vegetative propagation success of leafy stem schefflera cuttings. Results Fusarium foeten (strain 1) and Fusarium falciforme (strains 2 and 4) were first identified as root rot and wilt pathogens of schefflera in Egypt based on morphological features and confirmed with molecular analyses. Fusarium foetens (strain 1) and F. falciforme (strain 2) have the most aggressive action, as the infection percentages significantly increased in the pathogenicity test. The disease incidence reached 38.88 and 44.44%, respectively, whereas the disease severity was 18.51 and 26.84%, respectively. Chitosan nanoparticles at a concentration of 25 mg/L were the most effective dose, leading to a significant reduction in disease incidence to 25.00%, disease severity to 4.17%, and playing a vital role in activating plant defense, which correlates well with improved growth characteristics. The novel strategy of L-proline loaded on chitosan nanoparticles (LP-CSNPs) application occupied the first rank at protective influence against root rot and wilt disease-induced oxidative stress, signaling a defensive function that was freelance verified. L-proline loaded on chitosan nanoparticles (LP-CSNPs) at 0.125–0.25 g/L had a significant impact on reducing the incidence and severity of root rot and wilt diseases, as well as improving photosynthetic pigments and free radical scavenging activities, which included strengthening plant defense and further validating the findings from the biochemical trait analysis. The TT biplot graph was an influential statistical tool to study the impacts of treatments on schefflera production and its attributes and to discover the interrelationships among them. Conclusions Applying LP-CSNPs is one of the best techniques to manage schefflera root rot and wilt diseases, since it can be utilized as a growth stimulator and defense activator with sustainable increased efficiency. Graphical Abstract

Identification and Application of Streptomyces rapamycinicus CQUSh011 against Potato Late Blight.

Using chemical fungicides is the main strategy for controlling potato late blight (PLB), a devastating pre- and postharvest disease caused by Phytophthora infestans, resulting in environmental pollution and health risks. It is of great importance to develop a biofungicide from microorganisms. Through isolating potato rhizosphere microorganisms, CQUSh011 was found to have antioomycete activity with strong inhibition on vegetative growth and virulence of P. infestans. Morphological and molecular identification indicated that CQUSh011 belongs to Streptomyces rapamycinicus. Based on genome, metabolome, and HPLC quantification, rapamycin and salicylic acid were found to be the two active metabolites against P. infestans. Continuous field trials showed that CQUSh011 has sustainable control efficiency against PLB, and the efficiency was better when combined with Infinito, along with an increased endophytic microbial community and biodiversity in potato roots. The results demonstrated the potential of CQUSh011 as a biofungicide against PLB and provided an alternative strategy for reducing the application of chemical fungicides.

Proteome Profiling of Cucurbita pepo Phyllosphere After Infection by Podosphaera xanthii and Application of Reynoutria sachalinensis Extract

Podosphaera xanthii is the main causal agent of powdery mildew (PM) disease for Cucurbita pepo. Disease control is attained principally by applications of chemical fungicides, along with parallel use of tolerant crop varieties and alternate application of elicitors to control development of disease resistance. To get insight into C. pepo molecular responses to P. xanthii infection and elicitor treatment we studied the proteomic profile differences at the phyllosphere of a zucchini cultivar susceptible to PM, at the onset of P. xanthii (PX) infection and after application of Reynoutria sachalinensis (RS) plant extract, respectively, using a nano-LC-HRMS/MS, Q-Exactive-Orbitrap approach. Analysis of peptide sequences regarding four treatment groups (Control; PX; RS; and RSPX (PX-infected priorly treated with RS)) resulted in 2070 CuGenDB annotations. Three comparisons (treatments vs. Control) encompassed most of the Differentially Expressed Proteins (DEPs). In these three comparisons, KEGG and Gene Ontology functional analyses highlighted unique differentially enriched pathways—some of which included highly expressed proteins—in PX-related (proteasome, pentose phosphate pathway, and carbon fixation), RS-related (biosynthesis of secondary metabolites, flavonoids, and starch and sucrose metabolism), and RSPX-related (pyruvate metabolism and polycomb repressive complex) comparisons, respectively, suggesting distinct mechanisms of early plant responses modulated by PX and RS. Furthermore, in four out of six comparisons the thiamine metabolism pathway was found to be enriched, suggesting a pivotal role in PX-induced responses.

Chitosan Based Edible Coatings: Enhancing Shelf Life and Quality in Fruits and Vegetables

Chitosan-based edible coatings have gained considerable attention as a sustainable solution for harvested fruits and vegetables which are highly prone to post harvest decay and quality deterioration during storage. Chitosan, derived from chitin exhibits biocompatibility, biodegradability and antimicrobial properties making it an ideal material for edible coatings. Edible coating act as effective barriers to moisture loss, gas exchange and microbial contamination thereby enhancing the quality and extending the shelf life of produce. Research has shown that chitosan coatings can significantly reduce respiration rates, inhibit enzymatic browning and preserve the sensory qualities of fruits and vegetables, contributing to a reduction in food waste and improved food security. The effectiveness of chitosan based coating is influenced by factors such as chitosan concentration, the addition of other natural additives and the methods of application. Studies have demonstrated that chitosan coatings alone or in combination with essential oils or plant extracts effectively reduce weight loss, maintain firmness and prevent spoilage in horticultural perishables. Additionally, nano-encapsulated chitosan formulations have been explored for their enhanced protective effects offering more uniform coatings with superior barrier properties. The application of chitosan coatings is expected to evolve with the integration of nanotechnology, the development of functionalized chitosan molecules and the use of biocompatible additives. Chitosan coatings have been successfully applied commercially, such as in the preservation of perishables illustrating their potential as a sustainable solution with practical benefits for both scientific advancement and industrial application These innovations will further improve the efficacy of coatings by enhancing their moisture and gas barrier properties along with antimicrobial and antioxidant properties. Additionally, sustainability concerns are driving research into eco-friendly sources of edible coating and chitosan is a promising alternative to synthetic or chemical ingredients or fungicides. As the technology advances, chitosan based edible coatings are likely to have increased commercial adoption due to its sustainable and biodegradable nature. However, Chitosan-based coatings face challenges with solubility, application consistency, scalability, cost, allergen concerns, and varying regulatory standards.

Biocontrol potential of Bevibacillus brevis HK544 for fungal plant diseases

Chemical fungicides have been widely used to control plant diseases caused by fungal pathogens. Still, the overuse of these fungicides has led to concerns about the hazards to humans, animals, and the environment and an increase in fungicide resistance. Interest in biocontrol agents with strong antimicrobial activity has significantly increased to counteract the escalating risks of chemical fungicides. Our previous study found that a soil-born microbe, Brevibacillus brevis HK544, exhibited a promising antifungal activity against a plant pathogen, Fusarium graminearum, with edeine B1 identified as the active compound. Herein, we extended our study to investigate the in vitro and in vivo antifungal spectrum of B. brevis HK544, including edeine B1, against various plant pathogenic fungi and evaluated the possibility that B. brevis HK544 could be used in combination with chemical fungicides to enhance the disease control efficacy. With an in vitro broad-spectrum antifungal activity, the B. brevis HK544 culture filtrate, culture broth, and metabolite edeine B1 exhibited a promising disease control efficacy against tomato gray mold and tomato late blight among the tested fungal diseases. Based on the in vitro antifungal activity against Botrytis cinerea, when edeine B1 was combined with various chemical fungicides, the highest average synergy score among the tested combinations was observed in the edeine B1 and benomyl combination. The co-application of the B. brevis HK544 culture filtrate and benomyl improved the disease control efficacy against gray mold disease, supporting the in vitro result. Taken together, our results show that B. brevis HK544 has potential as a biological control agent for controlling plant pathogenic fungi and also that B. brevis HK544 could be combined with chemical fungicides to enhance the efficacy of antifungal agents.

ENDOPHYTIC MICROORGANISMS AS BIOCONTROL AGENTS: AN ALTERNATIVE FOR SUSTAINABLE AGRICULTURAL PRODUCTION SYSTEM

Endophytic microorganisms emerge as a sustainable alternative, offering benefits to plants, such as increased resistance to stress and pathogens. This research aims to conduct a literature review on the potential of endophytic microorganisms in the biological control of pathogens in agricultural systems, as a sustainable alternative to traditional methods. Endophytes can act directly on insects or colonize plants, creating a natural defense against pests. They also show promise in the control of phytopathogens, helping to reduce the use of chemical fungicides and encouraging more sustainable agricultural practices, producing bioactive compounds with effective antifungal activity against pathogens. In addition, they show potential as natural herbicides, negatively affecting the germination and development of weeds. Although more research is needed on the potential of endophytes in agricultural systems, they show great promise for more sustainable management.

Suppression of Thielaviopsis ethacetica wilt and root rot, the emerging pathogen on bell pepper (Capsicum annuum), and plant growth promotion properties by the safety indigenous Streptomyces SBcT04

Thielaviopsis ethacetica is an emerging pathogen responsible for wilt and root rot in bell peppers, significantly impacting crop yield. Biological control of the fungal pathogen provides significant advantages as a safe and efficient alternative to excessive chemical fungicides for managing plant diseases. Studying the screened and selected potential actinomycete strain from the indigenous collection is a quick and efficient measure to protect the yield of local bell pepper crops. The research assessed the indigenous actinomycete's ability to inhibit plant pathogens and promote plant growth both in vitro and in vivo. The Streptomyces SBcT04 was the most effective against T. ethacetica TROC-2 pathogen in vitro. The inhibition percentage reached 89.15 ± 0.46%. SBcT04 also effectively promoted plant growth properties in vitro. This strain fixed nitrogen and produced substantial amounts of indole-3-acetic acid (IAA), siderophores, and enzymes. Furthermore, the safety characteristics of SBcT04 for both the host plant (in vivo) and animals (in vitro) were confirmed. Streptomyces SBcT04 significantly processed pathogens, resulting in a reduction of approximately 40% in disease severity. Additionally, SBcT04 significantly promoted the host plant's growth, even in the presence of T. ethacetica TROC-2 infection. The indigenous Streptomyces SBcT04 efficiently inhibited T. ethacetica and significantly enhanced bell pepper plant growth. These advantageous characteristics of SBcT04 indicate its potential to foster secure and sustainable local bell pepper agricultural output.

Potential Use of Algae and Seaweed Extracts as Protection Against Peach Leaf Curl

Abstract Plant pathogenic fungi are a major cause of plant diseases, contributing significantly to the global decline in food production. Their proliferation results in substantial crop losses, fruit and vegetable deterioration, reduced food accessibility, and billions of dollars in economic losses annually. While synthetic chemical fungicides are commonly used to combat fungal diseases, their environmental impact is concerning. Marine algae provide a sustainable alternative, offering diverse compounds with industrial applications and presenting an eco-friendly solution. Taphrina deformans is responsible for peach leaf curl, a widespread disease in peach trees that can severely impact crop productivity and tree lifespan. Seaweeds and algae, encountering various biological interactions and extreme abiotic conditions, have evolved defense mechanisms, including the production of biologically active substances. In our study, we investigated the efficacy of water extracts from six algae (Nannochloropsis sp., Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira weissflogii, Tisochrysis lutea, Chlorella vulgaris), four seaweeds (Palmaria palmata, Chondrus crispus, Ascophyllum nodosum), and one cyanobacterium (Arthrospira platensis) at two different concentrations (1% and 3%) in suppressing the outbreak of peach leaf curl disease in vivo on peach trees. The spray was applied twice in spring just before budbreak. Algae and seaweed extracts showed significant suppression of peach leaf curl outbreaks on peach trees compared to controls. Following the application of water extract of Chlorella vulgaris at both concentrations, the lowest incidences of symptomatic disease expression were observed (1.00 ±0.00% and 0.25 ±0.50%). Algae and seaweed extracts demonstrate potential in controlling leaf curl disease in peach trees.

Financial Determinants of Adoption of Agricultural Technologies in Irish Potato Production in Ol Kalou Sub County, Kenya: Application of Multinomial Logistic Regression

Irish potato is a significant source of food and income for many households worldwide. The demand for the crop has steadily increased around the globe. Kenyan Irish potato farmers have the potential to produce about 30 tonnes per Ha. However, small-scale Irish farmers in the country realize low output ranging from 4-8 tonnes per Ha due to limited uptake of agricultural technologies. This study aimed to analyze the financial factors influencing the uptake of agricultural technologies in Irish potato production in Ol Kalou Sub County. The agricultural technologies under investigation were chemical fertilizer, certified seeds, fungicides, and farm machinery. Production and innovation diffusion theories guided the study. Descriptive cross-sectional research design was used to obtain data from a study population of 21,942 smallholder Irish potato farmers in Ol Kalou Sub County. A multiple-stage sampling technique was employed to give a sample size of 385 respondents small scale Irish potato farmers, where data was collected through a semi-structured questionnaire. Data collected was analyzed using multinomial logistic regression through SPSS version 28 and STATA version 17. The model indicated that off-farm income, access to credit, and production risk had a positive and significant influence on adopting agricultural technologies. Conversely, production cost had a negative and significant influence on the adoption of agricultural technologies, while the availability of subsidies had no significant influence. The Marginal effect analysis showed that the availability of off-farm income increased adoption by 22.00%, the increase in credit increased adoption by 2.00%, the availability of mitigation measures of production risk increased adoption by 19.00%, while the increase in production cost decreased adoption by 7.00%. The study concluded that off-farm income, credit facilities, production risk and cost of production influence the adoption of agricultural technologies. The study recommended that the government should develop policy regulations such as diversification of income, grants that reduce production costs, credit incentives, and crop insurance.

Antifungal activity of citral against Fusarium wilt in tomatoes and induction of the upregulation of glucanase, chitinase, and thaumatin-like protein plant defense genes

Fusarium wilt of tomatoes, caused by the soil-borne fungus Fusarium oxysporum f. sp lycopersici (FOL), is one of the devastating diseases of tomatoes, causing substantial economic losses worldwide. It is primarily controlled with chemical fungicides. The present study assessed the antifungal activity of citral against FOL under greenhouse conditions and investigated its effects on three plant defense genes: glucanase, chitinase, and thaumatin-like protein (TLP) using Real-time- quantitative PCR (RT-qPCR). Greenhouse experiments demonstrated that citral oil at 1024 and 512 µg/mL significantly reduced wilt severity from 61.7 % to 28.3 and 33.3 %, respectively. RT-qPCR results revealed that citral upregulates the expression of the three defense genes to varying extents, highlighting their role in resistance induction in tomatoes against FOL. Chitinase showed the highest differential expression with a 9.54-fold increase at 12 hours post-treatment (hpt), followed by TLP with a 6.96-fold increase at 12hpt, and glucanase with a 3.68-fold increase at 24hpt. These findings suggest citral is a promising biocontrol agent against fusarium wilt in tomatoes. However, field trials are recommended to validate these results under open field conditions.

Citrus bliss: potassium, sodium, and calcium silicates secrets for post-harvest diseases of fruit defense

Biotic stress significantly challenges the global citrus industry. Major post-harvest issues include diseases caused by Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, Alternaria alternata, and Phytophthora citrophthora. The negative impact of chemical fungicides on the environment and health necessitates eco-friendly alternatives. This study examines the effectiveness of sodium, potassium, and calcium silicates against common citrus diseases. In vitro tests evaluated mycelial growth inhibition using silicate concentrations from 0 to 10,000 ppm after 7 days at 25°C. Sodium silicate showed the highest efficacy, completely inhibiting P. digitatum and P. italicum at 2000 ppm. Potassium and calcium silicates achieved 100% inhibition against Penicillium spp. at a concentration of 1%. In vivo tests on Sidi Aissa clementines assessed the preventive and curative effects of 1, 2, and 6% silicate salt solutions. Sodium silicate prevented 41% of brown rot, 72% of sour rot, and 100% of green mold at 6%. Calcium silicate at 6% significantly reduced blue mold and black rot by 32% and 74%, respectively. Sodium silicate was most effective in curative treatments, suggesting its potential as a pre- or post-harvest spray to control P. digitatum, P. italicum, and G. citri-aurantii.

Study on antifungal properties of modified chitosan combined with essential oil and its application in preserving fruits

The presence of chemical pesticides has an impact on human health and there is an urgent need for the development of green antifungal alternatives. This study investigated the freshness application of dehydroabietic acid-modified chitosan product (CSDA) mixed with three essential oil (litsea cubeba oil (LCO), wintergreen essential oil (WEO), cinnamon essential oil (CEO)). The antifungal activity of modified chitosan/essential oils was tested by the punching method and the antifungal mechanism was investigated by the transmission electron microscope (TEM). The results showed that fungal inhibition rate of CSDA-WEO on Penicillium digitatum reached 100% at a concentration of 0.05 μL/mL and on Penicillium italicum reached 100% at a concentration of 1 μL/mL. Both molds were not well inhibited by CSDA-LCO and CSDA-CEO. CSDA-WEO was able to affect the cell walls and energy metabolism of the molds, resulting in nutrient loss and death. Fruits were preserved with 0.1 mg/g CSDA and 1 μL/mL WEO. CSDA-WEO maintained the antioxidant activity of citrus, inhibited respiration and water loss, and extended shelf life up to 24 days. CSDA-WEO extended the shelf life of longan to 18 days and kiwi slices to 6 days. CSDA-WEO is expected to serve as an alternative to chemical fungicides and shows promise as a broad-spectrum fruit and vegetable preservative.

Production of chitinase in elicited tomato cell suspensions and its application as a biopesticide and fungicide against soil-borne pests and fungi

Soil-borne fungi and pests present significant challenges to crop production, causing diseases and reducing yields. This study explores the potential of producing chitinase from tomato cell suspension cultures and its application in controlling soil-borne fungi and pests. Tomato cell suspension cultures were established from seeds, and different elicitors—including chitin, fungal debris, and fungal metabolites—were used to optimize chitinase production. The enzyme was purified, and its physicochemical properties were characterized. Its antifungal activity was tested against various soil-borne fungi, while termiticidal activity was evaluated using four bioassay methods. Additionally, the nematicidal activity of chitinase was assessed against different stages of root-knot nematodes. Results indicated that chitin media induced the highest chitinase production and cell growth compared to other elicitors. The purified chitinase had a molecular weight of 34 kDa, with a maximum velocity (Vmax) of 0.940 μg NAG/min and a Michaelis constant of 1.236 mg colloidal chitin/mL. The turnover number (Kcat) was 1.598 μg NAG/min/mol chitinase. The enzyme exhibited a broad range of activity and stability across varying pH levels and temperatures, as well as remarkable stability under different storage times and in the presence of metal ions. Tomato-derived chitinase demonstrated superior antifungal, nematicidal, and termiticidal activities compared to common chemical fungicides and pesticides. Chitinase was successfully produced from tomato cell suspension culture in this study, highlighting its potential as a biocontrol agent for sustainable pest and disease management in agriculture.

Reexamining the Mycovirome of Botrytis spp.

Botrytis species cause gray mold disease in more than 200 crops worldwide. To control this disease, chemical fungicides are usually applied. However, more sustainable control alternatives should be explored, such as the use of hypovirulent mycovirus-infected fungal strains. To determine the mycovirome of two Botrytis species, B. cinerea and B. prunorum, we reanalyzed RNA-Seq and small RNA-Seq data using different assembly programs and an updated viral database, aiming to identify new mycoviruses that were previously not described in the same dataset. New mycoviruses were identified, including those previously reported to infect or be associated with B. cinerea and Plasmopara viticola, such as Botrytis cinerea alpha-like virus 1 and Plasmopara viticola lesion-associated ourmia-like virus 80. Additionally, two novel narnaviruses, not previously identified infecting Botrytis species, have been characterized, tentatively named Botrytis cinerea narnavirus 1 and Botrytis narnavirus 1. The analysis of small RNAs suggested that all identified mycoviruses were targeted by the antiviral fungal mechanism, regardless of the viral genome type. In conclusion, the enlarged list of newly found viruses and the application of different bioinformatics approaches have enabled the identification of novel mycoviruses not previously described in Botrytis species, expanding the already extensive list.

Comparative efficacy of different chemical fungicides against Sclerotium rolfsii (sacc.) causing collar rot of chickpea (Cicer arietinum L.)

Present investigation was undertaken for efficacy of fungicides like i.e., carboxin 37.5% + thiram 37.5% WS (vitavax), pyraclostrobin 100 g/L CS, propiconazole 25% EC, hexaconazole 5% EC, thiophanate methyl 70% WP, carbendazim 50% WP, mancozeb 75% WP, chlorothalonil 75% WP and captan 70% + hexaconazole 5% WP were evaluated in-vitro at three concentrations viz., 100, 125 and 200 ppm concentration against S. rolfsii on PDA by poisoned food technique. The result revealed that increase in concentration of the fungicides caused increased inhibition of mycelial growth of pathogen. Among these, carboxin 37.5% + thiram 37.5% WS (vitavax) was completely inhibited mycelial growth of pathogen at 100 ppm, 125 ppm & 200 ppm. Followed by hexaconazole 5% EC in mycelial growth inhibition of 95.44, 97.22 and 100% at 100, 125 and 200 ppm, respectively. At 200 ppm both hexaconazole 5% EC and carboxin 37.5% + thiram 37.5% WS (vitavax) is statistically at par in growth inhibition. While, mancozeb 75% WP was found least effective at all concentrations against S. rolfsii. Most effective in-vitro evaluate fungicides tested for their efficacy against disease under pot experiment along with treatment application methods viz., pre-emergence drenching, seed treatment and integration of both seed treatment and post emergence seedling drenching at 7 days after germination (7 DAG) against collar rot disease of chickpea in pot experiment. All the treatments proved significantly superior when compared with inoculated control. Maximum percent reduction in PESR (100.00%) was recorded in vitavax power applied through seed treatment followed by hexaconazole recorded (90.91%) reduction in PESR. Maximum percent reduction in PESM (62.50%) was recorded in hexaconazole applied through integration of seed treatment & post emergence seedling drenching at 7 DAG. Which, was followed by vitavax power observed (50.00%) reduction in PESM. Seed treatment alone reduced PESR while, integration of seed treatment and post emergence seedling drenching at 7 DAG also reduced PESM. Among treated pots highest grain yield recorded (45.90 g/pot) in hexaconazole applied through integration of integration of seed treatment and post emergence seedling drenching at 7 DAG followed by vitavax power (43.33 g/pot).

Biocontrol potential of Burkholderia gladioli STPT16 on postharvest decay of litchi fruit caused by Peronophythora litchii and Colletotrichum fructicola

Litchi downy blight (LDB) caused by Peronophythora litchii and anthracnose (AD) caused by Colletotrichum species are major pre- and postharvest disease of litchi fruit. Biocontrol agents such as Burkholderia has been applied for controlling postharvest fruit decay. In this work, an endophytic strain SZPT16 isolated from health litchi branch was identified as Burkholderia gladioli and exhibited strong antagonistic activity against mycelial growth and conidia/sporangia germination of two postharvest pathogens. Dual incubation of pathogen and biocontrol agents caused alterations in hyphal and conidial/sporangial structures and severe cell morphology changes such as mycelia deformation, cell wall collapse and cellular disorganization. Cell-free culture filtrates (CF, diluted at 25-fold) of B. gladioli SZPT16 showed an efficient inhibition on postharvest litchi decay by preharvest application (74.77 % protection) and postharvest application (64.68 % and 71.14 % protection for LDB and AD, respectively). Furthermore, UPLC-MS/MS metabolomic analysis identified 41 up-regulated differential metabolites, which mainly included nucleosides, nucleotides, and analogues, organic acids and derivatives, organic oxygen compounds, and organoheterocyclic compounds. This study firstly reported the efficacy of CF of B. gladioli SZPT16 in protecting postharvest litchi fruit against natural and inoculated pathogen infections. The overall results provide a promising alternative to chemical fungicides to control litchi postharvest decay.

Economic impact, pathogen identification and management of blossom and peduncle blight in tuberose: A review

In the global floriculture industry, tuberose [Agave amica (Medik.) Thiede & Govaerts syn. Polianthes tuberosa L.] holds significant economic and cultural value, particularly in regions like Tamil Nadu, India. However, the cultivation of this valuable flower is increasingly threatened by diseases such as blossom blight and peduncle blight. This review examines the economic importance of tuberose and the severe impact of these blights, caused by Fusarium equiseti and Lasiodiplodia theobromae respectively, which canresult in crop losses of up to 43 %. The identification and morphological characteristics of these pathogens are discussed, emphasizing the need for accurate detection and diagnosis to manage these diseases effectively. This article also reviews current management strategies, including chemical fungicides, biocontrol agents and cultural practices, highlighting the efficacy of carbendazim and tebuconazole against L. theobromae and the potential of Aimcozim and organic amendments against F. equiseti . Climate change exacerbates the impact of these diseases, necessitating adaptive management practices. Despite progress, research gaps remain in developing integrated disease management strategies and understanding the long-term effects of climate change on disease epidemiology. This review aims to provide a comprehensive overview of the current knowledge and to encourage further research, with the goal of enhancing the sustainability of tuberose cultivation in the face of these increasing challenges.

Bacillus velezensis B105-8, a potential and efficient biocontrol agent in control of maize stalk rot caused by Fusarium graminearum.

Maize stalk rot (MSR), caused by Fusarium graminearum, is the most serious soil borne disease in maize production, seriously affecting maize yield and quality worldwide. Microbial biocontrol agents are the best means of controlling MSR and reducing the use of chemical fungicides, such as Bacillus spp. In the study, a soil-isolated strain B105-8 was identified as B. velezensis (accession No. PP325775.1 and No. PP869695.1), demonstrated a broad spectrum against various pathogens causing maize diseases, which effectively controlled MSR, exhibited a high control efficacy of more than 60% and growth-promoting effect in the pot plant. B105-8 could effectively improve soil urease (S-UE), invertase (S-SC), and catalase (S-CAT) activities. S-NP activity showed an initial increase with a peak of 20,337 nmol/h/g, followed by a decrease, but activity remained significantly better than control treatment with chemical fungicides. The application of B105-8 repaired the damage caused by F. graminearum on soil activity. The antifungal compound B-1, extracted from B105-8, was purified using a protein purifier, revealing inhibitory effects against F. graminearum. Mass spectrometry analysis indicated the potential presence of C14 Bacillomycin, C15 Iturin, C15 Mycosubtilin, C17, and C15 fengycin in B-1. In pot experiments, a 5 μL/mL concentration of B-1 exhibited 69% control on MSR, enhancing maize root elongation, elevation, and fresh weight. At 10 μL/mL, B-1 showed 89.0 and 82.1% inhibition on spore production and mycelial growth, causing hyphal deformities. This study presents the innovative use of B. velezensis, isolated from maize rhizosphere in cold conditions to effectively control MSR caused by F. graminearum. The findings highlight the remarkable regional and adaptive characteristics of this strain, making it an excellent candidate to fight MSR in diverse environments. In conclusion, B. velezensis B105-8 demonstrated potential as a biocontrol agent for MSR.