Fungicides Mancozeb Research Articles

Influence of Plant Density and Fungicides on Downy Mildew (<i>Peronospora Destructor</i>) and Bulb Yield of Onion in Ethiopia

Onion is a popular vegetable crop, which has been produced for its daily uses and economic benefits. Downey mildew caused by the fungus <i>Peronospora</i> <i>destructor</i> is among the most important yield-reducing factor in onion production. The effect of three different levels of plant population and fungicide frequency with two different fungicides was studied on downy mildew severity and yield of onion. Nineteen treatment of this Experiment included two fungicides mancozeb + metalaxyl and copper hydrox-ide, three different spraying interval with (10 days, 15 days and 21 days) and three level of plant population (0.71, 0.95 and 1.2 million plants/ha). The experiment was laid out in a randomized block design with three replications for two year at Fogera and for one year at Dera districts of South Gondar zone Ethiopia. Data on disease severity, bulb yield, bulb number and bulb size were recorded during the time of harvest. The price of bulb yield was assessed from the local market and the total price of the yield obtained from each treatment was computed on hectare basis. Input costs like seed, fungicides and labor were converted into hectare basis according to their frequencies used. Fungicides cost was estimated based on the price of the local market. Cost of the labor was in Birr per man-days; cost of spray and spray equipment to spray per hectare were also calculated. Based on the obtained data from the above mentioned parameters economic analysis was performed. The lowest disease severity was recorded in treatment were lowest level of plant population (0.71 million plant/hectare) spraying with fungicide mancozeb + metalaxyl within 15days interval. In this treatment bulb yield and bulb weight were the highest. The economic evaluation showed that the highest net benefit with acceptable marginal rate of return was obtained from T3 (0.71million plants/ha spraying with fungicide mancozeb + metalaxyl within 15days interval).

Fungicides and Bioagents Are Used to Manage Downy Mildew on Pearl Millet

Pennisetum glaucum (L.), pearl millet Known by most as bajra, it is a significant warm-season grain that is mostly farmed in India under rainfed circumstances. In India, downy mildew caused by Sclerospora graminicola (Sacc.) Schroet is the most common and deadly disease affecting pearl millet. Two weeks after seeding, the illness was visible as chlorotic stripes on the leaf surface advanced from the base to the top. Most infected plants were unable to develop typical, healthy earheads. The bioagents that were examined as seed dressers were Trichoderma harzianum (6 g/kg seed), Pseudomonas fluorescens (8 g/kg seed), Trichoderma viride (6 g/kg seed), and neem oil and water. The downy mildew disease incidence was significantly reduced (2.83%) by the fungicides Mancozeb at 0.2%, Neem oil, Metalaxyl at 0.25%, and Carbendazim at 0.25%, as compared to the control, which had a documented disease incidence of 40.33%. Neem oil considerably outperformed all evaluated bioagent seed dressings for downy mildew prevention, including the seed dressing containing Pseudomonas fluorescens seed treatment at 8 g/kg seed was statistically comparable to Trichoderma harzianum seed treatment at 6 g/kg seed and Metalaxyl application at 0.25%. The downy mildew was also greatly reduced by foliar application of Mancozeb at 0.2 % and seed treatment with Metalaxyl (6 g/kg seed) + spray of Propiconazole at 25% EC at 0.25%; these two methods outperformed the seed dressing with all evaluated bioagents. The positive outcome of using neem oil topically suggests that, when it comes to managing downy mildew in pearl millet in an environmentally benign manner, it might replace fungicides.

Hepatotoxicity induced by subacute exposure of Mancozeb and Arsenic in Wistar rats: Mitigating effect of quercetin and catechin

BackgroundWidespread use of Mancozeb (MZ) fungicide in endemic areas having high levels of arsenic (As+3) in the groundwater is likely to cause toxicosis in humans and animals. Therefore, the present study aimed to determine the hepatotoxic effect of MZ and As+3 interaction in Wistar rats and mitigating potential of quercetin and catechin on such toxicity. MethodsSixty adult rats were randomly divided into 10 groups of 6 animals each. Group I served as control and group II was exposed to MZ (800 mg kg-1, PO). Groups III, IV, and V were provided drinking water containing As+3 at the rate of 10, 50 and 100 µg L-1, respectively. Groups VI, VII, and VIII were given drinking water containing As+3 at 10, 50 and 100 µg L-1, respectively, along with MZ. Groups IX and X received drinking water contaminated with 100 µg L-1, As+3 and MZ along with quercetin or catechin (50 mg kg-1 each), respectively. ResultsSignificant (p <0.05) alterations in hepatic biomarkers in blood, liver antioxidant status and hepatic histoarchitecture were observed in animals treated with individual toxicants in a dose-dependent manner, however, such toxicity-induced changes were more severe in co-exposed rats. The administration of quercetin or catechin significantly mitigated the dual toxicant administration-driven changes in biochemical markers of hepatic damage, hepatic antioxidant profile and liver histomorphology. ConclusionsBoth quercetin and catechin proved beneficial in reducing toxicant-induced oxidation-mediated hepatic damage as demonstrated by alleviation in altered levels of determinants of hepatic biochemical and oxidative stress parameters in addition to restoration of toxicant-induced histological alterations of hepatic tissue.

Novel Fungicide from Waste Oil Palm Fruit Bunch for Sustainable Management of Tomato Wilt Disease Caused by Fusarium oxysporum - experimental and in silico studies

Tomato wilt, a widespread and persistent disease caused by the fungus Fusarium oxysporum, can be effectively controlled through biological approaches, promoting ecosystem sustainability and enhancing agricultural productivity and quality. This study explored the use of empty oil palm fruit bunch (EOPFB) waste as a natural fungicide to control tomato Fusarium wilt disease through in vitro, pilot scale, and molecular docking experiments. EOPFB aqueous extract showed the highest mycelium growth inhibition of 68.3 %, with the commercial fungicide Mancozeb exhibiting a moderate 42.30 % inhibition, and sterile distilled water having a negligible effect of 0.24 %. The inhibition rate varied with concentration, peaking at 72.63 % at 0.15 g/mL and dropping to 54.80 % at 0.01 g/mL. In terms of wilt disease incidence and severity, EOPFB performed best, recording the lowest incidence of 47.20 % and severity of 15.58 %. Mancozeb followed closely, with an incidence of 46.30 % and severity of 26.23 %. Sterile distilled water, on the other hand, showed the highest incidence of 76.28 % and severity of 56.17 %. Molecular docking simulations corroborated the experimental results, validating the potency of EOPFB as an inhibitor of trypsin from F. oxysporum, and identifying 2-amino-5,6-dimethyl-3 H-pyrimidine-4-one as the primary active compound responsible for the fungicidal activity. This phytochemical, abundant in the crude ethanolic extract of EOPFB, was found to have a higher binding affinity (6.1 kcal/mol) than Mancozeb (4.8 kcal/mol), at the trypsin target. These findings demonstrate the potential of EOPFB, an agricultural waste product, as a sustainable and eco-friendly solution for managing tomato Fusarium wilt disease, contributing to increased tomato production. It also highlights the potential of 2-amino-5,6-dimethyl-3 H-pyrimidine-4-one as a lead compound for the development of novel, natural fungicides, and underscores the value of EOPFB as a rich source of bioactive compounds with agricultural and biotechnological applications.

Discrimination of Fungicide-Contaminated Lettuces Based on Maximum Residue Limits Using Spectroscopy and Chemometrics

The fast and effective monitoring of agrochemical residues is essential for assuring food safety, since many agricultural products are sprayed with pesticides and commercialised without waiting for the pre-harvest interval. In this study, we investigated the use of spectral reflectance combined with principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) to evaluate the discrimination of fungicide-contaminated lettuces, considering three maximum residue limits (MRLs) [3.5, 5, and 7 mg carbon disulphide (CS2) kg−1]. The non-systemic Mancozeb fungicide (dithiocarbamate) was adopted in this research. Spectral reflectance (Vis/NIR) was measured by a hand-held spectrometer connected to a clip probe with an integrating sphere. The lettuce spectra were pre-treated (centring, standard normal variate, and first derivative) before data processing. Our findings suggest that PCA recognised inherent similarities in the fungicide-contaminated lettuce spectra, categorising them into two distinct groups. The PLS-DA models for all MRLs resulted in high accuracy levels, with correct discriminations ranging from 94.5 to 100% for the external validation dataset. Overall, our study demonstrates that spectroscopy combined with discriminating methods is a promising tool for non-destructive and fast discrimination of fungicide-contaminated lettuces. This methodology can be used in industrial food processing, enabling large-scale individual analysis and real-time decision making.

Resistance of Ascochyta rabiei isolates from chickpeas (Cicer arietinum L.) to fungicides

Ascochyta blight is a disease that causes significant yield losses in chickpea crops in Turkey under favorable environmental conditions. The fungal pathogen Ascochyta rabiei is the causative agent of this disease. The antifungal activity of previous fungicides against A. rabiei was not effective due to the heterothallic nature of the fungus. The aim of this study was to determine the sensitivity of A. rabiei to fungicides (25.2 g kgˉ1 boscalid + 12.8 g kgˉ1 pyraclostrobin; 50 % tebuconazole + 25 % trifloxystrobin; 62.5 g Lˉ1 propiconazole + 37.5 g Lˉ1 azoxystrobin; 80 % thiram; 80 % kükürt (sulphur); 80 % mancozeb; 80 % maneb) under in vitro and field conditions. Pure cultures of A. rabiei were isolated from infected chickpea plants collected in Boğazlayan, Sarıkaya, Sorgun, Merkez and Yerköy. A total of 14 A. rabiei isolates and 4 references were evaluated. The field test was conducted at Yozgat Bozok University, Yerköy Agricultural Application and Research Center Station. The trials began on March 14, 2021. The experimental area was divided into plots and the susceptible chickpea variety Sarı98 was used for the study. Two artificial inoculations were carried out approximately on the 40th and 80th days after sowing. Twenty-four hours after inoculation, the chickpea plants were sprayed with the fungicides Nativo® WG 75, Bellis®, Dikotan® M45 and Thiovit Jet® using a handheld sprayer. In vitro testing revealed that A. rabiei was resistant to kükürt (sulphur), thiram, maneb, and mancozeb. A field study showed that the percentage of A. rabiei isolates treated with the mancozeb fungicide was between 14 and 21 % of the control. Therefore, effective disease management strategies should include not only the use of fungicides, but also alternative approaches such as the use of resistant varieties. Moreover, the study focused on phenotypic resistance and suggests that future research should investigate the genetic and molecular mechanisms underlying A. rabiei resistance to enable better resistance management.

Unveiling the biocontrol potential of Pseudomonas syringae through seed biopriming against charcoal rot disease in maize

In Punjab, Pakistan, maize production faces a significant threat from charcoal rot disease, caused by the soil-borne fungus Macrophomina phaseolina. To mitigate this issue and ensure food safety, researchers explored the potential of Pseudomonas syringae, a harmless gram-negative bacterium against charcoal rot disease in maize. Maize seeds treated with P. syringae (PS) were planted in soil containing the charcoal rot fungus in pot experiments. The outcome was then compared with the impact of NPK fertilizers and mancozeb fungicide. The positive control, with M. phaseolina alone, exhibited high disease severity resulting in a greater reduction of 30–70 % in the plant's biophysical and biochemical traits. Mancozeb, NPK, or PS, managed 66, 41, and 55 % of diseases and improved the biophysical and biochemical traits of the plants by up to 200 %. Applying P. syringae in combination with the recommended dose of NPK was found as the most promising treatment which significantly improved plant resistance by managing 90 % of disease through improving growth and biochemical traits (up to 300 %). This research suggests effective control of M. phaseolina by combining P. syringae with NPK, enhancing plant defense mechanisms and potentially improving pathogen-induced resistance in the maize plants.

Exploring Natural Solutions: Botanical Approaches for Controlling Early Blight in Tomato Plants under Laboratory Conditions

Around the world, Alternaria solani is the culprit behind the deadly and devastating early blight of tomatoes. To control the mycelial growth of A. solani in this investigation, a concentration of 10% for each plant extract was examined using the poison food technique. In comparison to the control, the pathogen mycelial growth was greatly suppressed by all examined extracts. With a 90.54% inhibition at 10% concentration, garlic clove extract proved to be the most successful of the extracts. Other extracts that showed promise were neem leaf extract (87.83%), ginger (83.78%), eucalyptus (75.67%), bael (71.67%), onion bulb extract (68.67%), and ashwagandha (63.51%). On the other hand, with a mycelial growth of 35 mm and 52.70% inhibition, lantana proved to be the least successful. After seven days of incubation at 24°C, the chemical fungicide mancozeb proved to be the most effective overall, offering a 93.24% inhibition at a 0.25% dose. Chemicals pose health dangers even though farmers use them extensively to control tomato rot. This study provides useful information for farmers by highlighting appropriate plant extracts as less risky substitutes for treating tomato early blight.

Integrated Management of Stem and Root Rot of Cowpea Caused by Macrophomina phaseolina (Tassi.) Goid. using Fungicides, Bioagents and Organic Manures

Background: Cowpea crop is affected by various biotic and abiotic stresses which are responsible for its poor quality and low yield resulting in severe economic losses. Among the root diseases, stem and root rot caused by Macrophomina phaseolina is an important disease causing the yield losses ranging from 50-55 per cent. So, there is a need to formulate suitable management practices against root rot. Methods: Field experiment was laid-out in a randomized complete block design with three replications at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad during rabi 2021-22 and 2022-23 to determine the efficacy of economically viable and effective fungicides, bioagents and organic manures against stem and root rot of cowpea. The per cent disease incidence and yield per hectare were taken into consideration for statistical analysis. Result: In laboratory experiments, it was found that, the seed dressing fungicides mancozeb 50% + carbendazim 25% WP and carboxin 37.5% + thiram 37.5% DS were the most effective against M. phaseolina. Similarly, among the bioagents tested, T. harzianum was the most effective followed by T. Viride and P. fluorescens. A two-years evaluation of nine integrated treatment modules for rabi seasons revealed that, seed treatment with carboxin 37.5% + thiram 37.5 % WS resulted in the lowest disease incidence and the highest grain yield, 100 seed weight and B:C ratio. Cowpea stem and root rot incidence was increased with soil temperature and decreased with soil moisture.

Biocontrol potentials of Trichoderma species in the control of Fusarium wilt in five tomatoes (Lycopersicon esculentum L.) varieties cultivated under greenhouse conditions in Southwest Nigeria

Important pathogenic fungi such as Fusarium species are mostly associated with the wilting of tomato plant leaves and constitute a serious limiting factor for tomato production. Therefore, this study aimed to screen tomato varieties commonly cultivated in Nigeria to determine their host resistance status to Fusarium oxysporum. The treatments included Trichoderma asperellum, T. harzianum, and Mancozeb fungicide. Data recorded included the incidence and severity of the pathogen, plant height, leaf number, and fruit yield of the tomato plants. Tomato plants grown with Trichoderma sp. exhibited better performance in terms of average fruit yield count of 6.5 for T. asperellum and 6.7 for T. harzianum compared to the average yield of 1.7 fruit count for Mancozeb fungicide. The lowest disease incidence was recorded in the variety 3 (NGB00737) with a 5.81% incidence in the Mancozeb-treated plants. Conversely, T. asperellum-treated plants in variety 3 (NGB00737) had the highest disease incidence of 46.49%. For variety 4 (NGB00695), plants treated with Mancozeb had the least disease with a severity rating of 1. Similarly, variety 5 (NGB00725) plants treated with T. asperellum showed the least disease severity rating of 1. All other treated plants showed higher severity values of 4. The Trichoderma species also improved the fruit yield and some agronomic parameters of the tomato plants compared to the chemical control. Agro-business enthusiasts, commercial growers and local farmers are therefore encouraged to further exploit the potential of Trichoderma species as means of control for fungus-based diseases in tomato plants such as those caused by Fusarium.

Compatibility study of Trichoderma sp. with Chemical Fungicides Commonly Used by Nepalese Farmers, Under In-Vitro Condition

The excessive use of synthetic fungicides has led to the emergence offungicide-resistant strains of pathogens, raising concerns about human health andenvironmental impact. Trichoderma spp., an endophytic and versatileopportunistic plant symbiont, has recently gained popularity as a biocontrolagent. Integrated use of Trichoderma with compatible fungicides gives betterdisease management and causes less harm to the environment in the long run.This study aimed to evaluate the compatibility of six fungicides commonly used byNepalese farmers at concentrations of 250, 500, and 1000 ppm with Trichodermasp. using the poisoned food technique in-vitro. The experiment was conducted ina completely randomized design with four replications for each treatment, anddata were taken at 24, 36, 48, 60, and 72 hours after incubation. Among thefungicides tested, Mancozeb was compatible at all concentrations from the startand exhibited the highest compatibility at 72 hours, with a growth inhibitionpercent of 0.39%. Metalaxyl+Mancozeb at 250 and 500 ppm, and Copperoxychloride at 250 ppm showed good compatibility. However, Carbendazim,Hexaconazole, and Carbendazim+Mancozeb resulted in 100% growth inhibition ofTrichoderma sp. throughout the experiment. While all treatments significantlyreduced mycelial diameter, Mancozeb and Metalaxyl+Mancozeb showed agradual decrease in growth inhibition percent over time, indicating increasedcompatibility. In contrast, Copper oxychloride demonstrated variable growthinhibition percent over time. So, the fungicides Mancozeb, Metalaxyl+Mancozeband Copper oxychloride at compatible concentrations can be used withTrichoderma sp. in integrated disease management to control soil and seed-bornepathogens.

Antioxidant and Antifungal Properties of Cinnamon, Cloves, Melia azedarach L. and Ocimum gratissimum L. Extracts against Fusarium oxysporum Isolated from Infected Vegetables in Mauritius.

Fusarium species, a group of economically destructive phytopathogens, are poorly studied in Mauritius where agriculture holds much significance. Furthermore, the increasing popularity of organic farming has prompted interest in alternatives to chemical fungicides. After gaining an overview of Fusarium prevalence in Mauritius fields through a survey, the pathogen was isolated from infected crops and identified based on morphological and molecular characteristics. Methanol and water extracts were then prepared from Melia azedarach, Ocimum gratissimum, cinnamon and cloves before determining their phytochemical profiles. Additionally, the antioxidant and antifungal effects of different concentrations of aqueous extracts were assessed. The isolate was confirmed as Fusarium oxysporum, and cloves inhibited its growth by up to 100%, especially at 60 and 90 g/L, with the results being significantly higher than those of the synthetic fungicide mancozeb. Over 50% inhibition was also noted for cinnamon and Ocimum gratissimum, and these effects could be linked to the flavonoids, phenols and terpenoids in the extracts. This study presented the aqueous extracts of cloves, cinnamon and Ocimum gratissimum as potential alternatives to chemical fungicides. It also confirmed the prevalence of Fusarium infection in Mauritius fields, thereby highlighting the need for additional studies on the pathogen.

Phytomediated zinc oxide and sulfur nanoparticles for management of soft-rot causing pathogenic fungi in ginger

Diseases management has been the greatest challenge to agriculture leading to huge crop failure, represented in low-profit production. Phytopathogenic fungi are among pathogens causing a variety of agricultural diseases. Various nanoparticles (NPs) have previously been employed to combat phytopathogenic fungi. Post-harvest deterioration due to fungal invasion is the most imperative cause of loss of ginger (Zingiber officinale) production. In the present study, four fungal pathogens isolated from soft-rot infected ginger were identified as Pythium spp. (isolate I and II), one Fusarium sp. (isolate III) and one Aspergillus sp. (isolate IV). Moringa oleifera mediated zinc oxide (ZnONPs) and sulfur nanoparticles (SNPs) were characterized by UV–Visible spectrophotometry and showed absorption maxima at 356 nm and 295 nm. Average size of NPs under Nanoparticle Tracking Analyzer was 78 nm and 26 nm respectively, confirmed by FESEM. Stable NPs with zeta potential of −14.1 mV (Standard deviation = 4.51 mV) and −21.1 mV (Standard deviation = 9.56 mV) were synthesized. FTIR detected the presence of various functional groups in NPs. In vitro antifungal activity was assessed by Kirby-Bauer disc diffusion assay and MIC values compared to antibiotic ketoconazole and fungicide mancozeb. Time kill assay represented the minimum time required by selected NPs to inhibit the growth of test pathogenic fungi. ZnONPs and SNPs can be used for further antifungal studies in the field as novel nanofungicides. Extrapolated and uncontrolled use can lead to the inhibition of germination, reduction in photosynthesis rate, and disruption of the plant roots. Thorough small-scale experimentation is necessary before commercialization.

Antifungal, antioxidant, and photocatalytic activities of greenly synthesized iron oxide nanoparticles

Abstract The build-up of synthetic dyes in the environment and aquatic ecology is a significant environmental issue due to their inability to break down naturally. The overuse of chemical fungicides also poses a threat to the environment due to their accumulation and fostering of fungal resistance. Hence, the study was conducted to detect the antifungal properties and photocatalytic activity of greenly synthesized iron oxide nanoparticles (IONPs) prepared using the Hibiscus sabdariffa flower extract. The biogenic IONPs showed the highest photocatalytic activity against rhodamine B dye at a concentration of 4.0 mg/ml. The biogenic IONPs also demonstrated effective antifungal properties against Penicillium digitatum and Aspergillus niger strains, with relative inhibition percentages of mycelial growth being higher than those with the metalaxyl + mancozeb fungicide at 800 ppm concentration. The efficient photocatalytic activity of the biogenic IONPs against rhodamine B dye and their effective antifungal properties suggest their potential use as safe substitutes for commercial fungicides.

Comparative efficacy of oxathiapiprolin-based fungicides in controlling late blight in field-grown potatoes induced by mixed mefenoxam-sensitive and resistant genotypes of Phytophthorainfestans

Potatoes are grown in Israel twice a year, in autumn and spring, contributing over $300 million to the state's economy in 2022. In both seasons late blight caused by the oomycete Phytophthora infestans is a major threat to yields. Fungicides are the most important means to control P. infestans. The classical fungicides mancozeb and chlorothalonil were banned by the regulator while mefenoxam, cymoxanil and infinito, suffer of reduced field efficacy. The new OSBPI fungicide oxathiapiprolin solo provides excellent control of the disease by foliar or soil applications but its proneness to resistance development enforces its application in mixtures with fungicides with a different mode of action. In three field trials done in Israel during 2021–2023, oxathiapiprolin solo and seven oxathiapiprolin-premixed fungicides were applied to potato crops Sifra or VR808 at early season. Plants were thereafter inoculated with mixed genotypes of P. infestans, sensitive and resistant to mefenoxam, and disease progress was monitored along 35 days after inoculation. All oxathiapiprolin products provided excellent control of the disease all along the season, significantly better than the fungicides mancozeb, mefenoxam, cymoxanil, ranman or infinito. Disease control was dependent on the dose applied, the proportion of oxathiapiprolin in the mixture, the partner fungicide, and the experiment. At the recommended dose of 0.1 % (50 g/ha in 500 L), the mixtures with mefenoxam or mandipropamid were more effective than the mixtures with chlorothalonil or azoxystrobin. At 0.2 %, all seven mixtures were highly effective all along the season. Tuber yields were significantly higher in plots treated with oxathiapiprolin mixtures as compared with control fungicide-free plots. Monitoring assays done along the season failed to detect oxathiapiprolin-insensitive mutants of P. infestans in all three trials, including plots treated with 0.2 % oxathiapiprolin solo (MIC = 0.3 ppm ai). We conclude that a single preventive application of oxathiapiprolin-based fungicides to potato crops at early season can provide effective control of late blight under heavy pressure of P.infestans for as long as 5 weeks without selecting for insensitive mutants.

Potential Test of Trichoderma harzianum and Trichoderma viridae Fungi as Agents for Degrading Fungicide Residues with Active Ingredient Mancozeb In Vitro

This study investigated the potential of the fungi Trichoderma viridae and Trichoderma harzianum in degrading the fungicide mancozeb. The research was conducted from May to October 2021 at the Plant Diseases Laboratory and Toxicology Laboratory, Department of Pests and Plant Diseases, Faculty of Agriculture, Universitas Brawijaya. The study comprised three stages. The first stage involved a preliminary test to assess the ability of T. viridae and T. harzianum to grow in media containing mancozeb-based fungicides. The second stage focused on evaluating the degradation of mancozeb using a bioassay, with the primary observation parameter being the biomass of T. viridae and T. harzianum. In the third stage, the mancozeb degradation process was assessed in vitro, with the observation parameters including the diameter of the pathogenic fungus Fusarium sp. and the percentage change in its diameter. Results demonstrated that T. viridae and T. harzianum could grow in media contaminated with mancozeb up to a concentration of 2 grams per liter. Furthermore, both fungi showed potential in degrading mancozeb, as evidenced by the increased growth of Fusarium sp. in treated media. It indicates that the application of T. viridae and T. harzianum reduces the toxicity of mancozeb. A t-test revealed that while there were differences between T. viridae and T. harzianum in their ability to degrade mancozeb, these differences were not statistically significant.

Removal of ethylene bisdithiocarbamate fungicides in wastewater and agricultural runoff by zinc oxide nanoparticles before analysis by HPLC and UV-Vis spectroscopy

This study developed an applied method based on the degradation to remove ethylene bisdithiocarbamate (EBDC) fungicides from wastewater and agricultural runoff by zinc oxide nanoparticles (ZnONPs). The synthesized ZnONPs were characterized using XRD for material crystallinity, scanning electron microscope (SEM) and particle size analysis (PSA) for surface structure, morphology and particle size (nm), respectively. The energy-dispersive X-ray spectroscopy (EDX) spectra confirmed the presence of zinc and showed that the synthesized zinc oxide nanoparticles were pure. Determination of the adsorption and photocatalytic degradation of Mancozeb (MCZ) fungicides based on ZnONPs was performed. Different amounts of ZnONPs were loaded into an MCZ fungicide solution in different concentrations. High-performance liquid chromatography (HPLC) and UV-Vis spectroscopy were used to determine the dithiocarbamate residue and the degradation efficiency of the synthesized particles. The particle size distribution of the synthesized ZnONPs was found to be in the range of 50-95 nm. At optimum conditions, with a ZnONPs dosage of 10 mg, (MCZ) fungicide concentration of 9.37 mg L-1, and a duration of 60 minutes, the degradation efficiency was surpassed at more than 95%. Additionally, the nanoparticles demonstrated excellent reusability and maintained efficient activity for up to three cycles.

Selected Leaf Diseases of Rubber: Symptoms and Control – A Review

This paper is a review article with the objective of providing valuable, recent and solid information and critical understanding of symptoms and control of selected leaf diseases of rubber tree (Hevea brasiliensis Muell. Arg) using secondary information and data harvested from previously published studies found online. Data gathered showed that H. brasiliensis is subject to a plethora of economically important diseases mainly of fungal origin, classified as leaf, stem and branch, panel and root disease. Some fundamental causal organisms of leaf diseases in H. brasiliensis includes Pseudocercospora ulei, Oidium heveae, Colletotrichum gloeosporioides and Corynespora cassiicola. Corynespora leaf fall caused by Corynespora cassiicola is currently accepted as the leaf disease which causes about 45% of yield loss to rubber in mostly Asian and African continents. The symptoms of South American Leaf Blight (SALB) range from discoloration of lamina to death of tree when untreated. Leaf disease symptoms range from white powdery patches to shriveling and falling off of tender leaves and translucent brownish yellow spots in semi-matured leaves in Oidium leaf disease. Colletotrichum leaf disease symptoms range from necrosis of tender leaves of young plants to defoliation and death of entire plant. Disease control is achieved by the use of chemicals and planting of disease-resistant varieties. Some phylloplane fungi are prospective biological control agents. The best treatment to manage Corynespora leaf fall disease (CLFD) in nurseries is the introduction of overhead shading coupled with application of the fungicide mancozeb. Diseases affecting the leaves of H. brasiliensis can be devastating and can lead to loss of multiple rubber trees and reduction in the latex production of the trees. Therefore, adequate preventive, curative and control measures against the diseases should be taking to ensure maintenance of a healthy rubber tree plantation.

Exploring Alternative Products for Tomato Septoria lycopersici Control

The septoriose (Septoria lycopersici) is an important disease in tomato production and can lead to significant losses. Although there are active ingredients registered for the control of this disease, there is little study about products with alternatives for the control of the fungus S. lycopersici. Thus, the objective of this work was to study the effect of alternative products in controlling the septoriose. The rationale for the study was to find efficient products that are less harmful to the environment. The study was conducted at the experimental station of EPAGRI in the state of Santa Catarina, Brazil. Twelve products were tested to control Septoria: Bacillus subtilis QST 713 (274 mg/L a.i.), Bacillus subtilis QST 713 autoclaved (274 mg/L a.i.), lime sulfur (10,000 mg/L c.p.), benzalkonium chloride (250 mg/L a.i.), mixed mineral fertilizer ( 2,000 mg/L c.p.), sodium hypochlorite (320 mg/L a.i.), peracetic acid (5,440 mg/L a.i.), Bordeaux mixture (3,000 mg/L c.p.), Viçosa mixture (3,000 mg/L c.p.), Trichoderma harzianum Rifai ESALQ-1306 (600 mg/L a.i.), acibenzolar-S-methyl (25 mg/L a.i.), potassium phosphite (2,000 mg/L a.i. with 1,340 mg/L phosphorous acid) and biostimulant (200 mg/L c.p.). The doses used were based on label, previous tests in vitro and in phytotoxicity events in tomato plants. In the in vitro experiments, the products that were not able to promote the formation of an inhibition halo were: biostimulant, potassium phosphite, acibenzolar-S-methyl, Trichoderma harzianum, Viçosa mixture and Bordeaux mixture. The products B. subtilis, lime sulfur, benzalkonium chloride, mixed mineral fertilizer, peracetic acid, sodium hypochlorite and autoclaved B. subtilis were able to inhibit fungal growth in vitro, forming a halo of inhibition. The chemical fungicides mancozeb + pyraclostrobin + fluxapyroxad were used as a positive control. In vivo, the positive control was able to control 100% of the incidence and severity of Septoria and no symptoms were observed in the plants. For incidence, the products that controlled at least 80% of the disease were lime sulfur and mixed mineral fertilizer. When considering the disease severity, the products that controlled at least 80% of the disease were: lime sulfur, mixed mineral fertilizer, Bacillus subtilis QST713 and benzalkonium chloride. The products Bordeaux mixture, Viçosa mixture, sodium hypochlorite and peracetic acid caused phytotoxicity when applied to tomato plants. Although lime sulfur has shown promise, its successive application can lead to a decrease in the photosynthetic rate.

Mancozeb associated with water deficit: Physiological and biochemical responses of soybean plants

Can oxidative stress from xenobiotics be intensified under water deficit conditions? Based on the hypothesis that the exposure to a xenobiotic aggravates the oxidative damages induced by water deficit, soybean plants were cultivated in pots eqquipped with soil water potential sensors to continuously monitor soil moisture levels. The experiment was conducted in 2020, in a protected environment, using a randomized block design with three replications. To comprehensively evaluate physiological and biochemical responses of plants, we conducted a range of analyses, including measurements of stomatal conductance, leaf temperature, chlorophyll, chlorophyll fluorescence, relative water content, membrane damage, electrical conductivity, lipid peroxidation, concentration of reactive oxygen species – hydrogen peroxide and superoxide, activity of antioxidative enzymes – ascorbate peroxidase, superoxide dismutase, catalase, non-enzymatic compounds – non protein thiols, nitric oxide and proline. Plants that received the application of the fungicide mancozeb showed 1 °C higher temperature compared to the control plants. Irrigated soybean plants had higher nitric oxide content when treated with mancozeb, but under water deficit the higher content was observed in control plants. No deleterious effects of mancozeb as a xenobiotic were observed when applied at the recommended dose for soybean cultivation, even under water deficit conditions. The plants exhibited deleterious effects caused by water deficit, particularly in relation to oxidative stress induced by water shortage. The combination of two stresses (water deficit and xenobiotics) did not result in the maximization of negative effects caused by water stress. By refuting the working hypothesis, it becomes evident that the application of mancozeb to plants under water deficit conditions did not exacerbate the damage induced by this stress. Responses to this combination are contingent upon various factors, including the stress duration, its severity, the plant species involved, and, in the case of xenobiotics, their inherent properties and mode of action within the plant.