Contact Fungicides Research Articles

In vitro evaluation of new molecules of fungicides against Colletotrichum capsici (Syd.) Butler and Bisby causing anthracnose of chilli

Chilli (Capsicum annuum L.) is the fourth major vegetable cultivated globally. The major fungal foliar pathogen causing havoc in production, export and marketing is fruit rot or anthracnose of chilli caused by Colletotrichum capsici (Syd.) Butler and Bisby which has emerged in impairing production in both tropical and subtropical regions. In the present study, new molecules of contact, systemic and combi product fungicides were tested against Colletotrichum capsici by poison food technique at different concentrations. The contact fungicides were tested at three concentrations (0.1, 0.2 and 0.3%) where, mancozeb 75% WP recorded 100 percent mycelial inhibition at all three concentrations. Among the systemic fungicides, propiconazole 25% EC and difenoconazole 25% EC showed 100 per cent mycelial inhibition at 0.025, 0.05 and 0.10 per cent. Among the combi product fungicides evaluated, metalaxyl 8% + mancozeb 64% WP showed 100 per cent inhibition which was on par with tricyclazole 18% + mancozeb 62% (99.54 %). Whereas, lowest mycelial inhibition was in zineb 75% WP (30.14 %), hexaconazole 5% EC (66.11 %) and tebuconazole 50% + trifloxystrobin 25% (72.36 %) in contact, systemic and combi fungicides respectively. The overall results suggest that the systemic fungicides of triazole group are highly effective in inhibiting mycelial growth.

Bio-efficacy of new fungicide, Tebuconazole- 430SC against coffee leaf rust disease, Hemileia vastatrix Berk and Broome

Coffee is an important plantation crop cultivated worldwide and used as stimulating drink. Coffee leaf rust (CLR) disease is one of the devastating disease affecting foliage of Coffee, limiting Coffee production worldwide. It is caused by an obligate parasite Hemileia vastatrix, which reduce photosynthetic area in turn results in heavy defoliation and die-back of branches. In India CLR management is accomplished with one contact fungicide spray (Bordeaux mixture @ 0.5%) and effective systemic fungicide spray during pre and post monsoon periods respectively. However, to find an alternative to the recommended fungicide the studies were conducted to know the efficacy of new fungicide Tebuconazole 430 SC against CLR. The results revealed that, in the laboratory conditions, complete inhibition of the uredospore germination was observed in Tebuconazole 430 SC @ 0.5 ml/L and 0.75 ml/L and Hexaconazole 5 EC @ 2 ml/L. However, in lower concentration Tebuconazole 430 SC @0.25 ml/L there was 98.97 per cent inhibition and in Copper Oxychloride 50 WP @ 5.5 g/L 87.49 per cent inhibition was observed over control. Field trials indicated that, at all the locations, Tebuconazole 430SC @ 0.75ml/L was found very effective which recorded maximum disease reduction followed by Tebuconazole 430SC @ 0.5ml/L which was found on-par with the currently recommended fungicide Hexaconazole 5 EC @ 2 ml/L and minimum disease reduction was observed in Copper oxychloride 50 WP @ 5.5g/L.

Zinc-dithiocarbimates for the control of Hemileia vastatrix: a versatile alternative.

The purpose of this work was to investigate the potential use of zinc-dithiocarbimate salts to control Hemileia vastatrix, the causal agent of the coffee leaf rust disease, and to evaluate their toxicity towards Apis mellifera, one of the most important coffee plant pollinators. Zinc-dithiocarbimate salts were prepared and fully characterized by infrared, proton (1 H) and carbon-13 (13 C) nuclear magnetic resonance and elemental analyses of carbon (C), hydrogen (H), nitrogen (N) and zinc (Zn). X-ray diffraction technique studies confirmed the proposed structures. The salts inhibited the germination of H. vastatrix spores in vitro, with a 50% inhibitory concentration (IC50 ) from 12 to 18 μmol.L-1 and a 90% inhibitory concentration (IC90 ) from 23 to 26 μmol.L-1 . Zinc-dithiocarbimate salts with the best in vitro results were selected for in vivo experiments with Coffea arabica var Caturra and with the pollinator A. mellifera. The results were similar to those of Mancozeb, a broad-spectrum contact fungicide, with a good control of the disease and low toxicity to the honeybee. The zinc-dithiocarbimate complex salts have potential to control coffee leaf rust, with low toxicity to the pollinator insect. © 2022 Society of Chemical Industry.

Management of Tomato Diseases in Plastic House at Lamjung

An experiment was conducted in plastic houses at three farmers’ field, each farmer as a replication, in three local levels (Sundarbazar, Gaunsahar and Besisahar) in Lamjung district during July to December 2017, to identify and manage major diseases of tomato (variety: Srijana) using chemicals and bio-pesticides. The treatments Bio-cure-B (Pseudomonas fluorescens: bio-fungicide) Bavistin Carbendazim, systemic fungicide) and Dithane M-45 (Mancozeb, contact fungicide) were applied as foliar spray. Control plot was maintained without application of any treatment. Mainly four fungal diseases, early blight (Alternaria solani), late blight (Phytopthora infestans), powdery mildew (Leveillula taurica), septoria leaf spot (Septoria lycopersici) and one bacterial disease (Xanthomonas campestris pv. Vesicatoria) were recorded. Mancozeb showed the best to control the disease incidence and severity of early blight (25%, 6.33%), late blight (18.0%, 14.34%) and septorial leaf spot (11.67%, 11.55%) repectively followed by Carbendazim, and P. fluorescens over control. However, Carbendazim was the best to control powdery mildew (6.0%, 2.0%), followed by Mancozeb and P. fluorescens over control. There were no significant effect of pesticides on bacterial leaf spot, plant height, and leaf number butconsiderable variation in fungal diseases, yield and average fruit weight.

In vitro evaluations of fungicides against Sclerotium rolfsii Sacc. Causing collar rot of chickpea

Collar rot of chickpea is caused by Sclerotium rolfsii. In vitro evaluation of fungicides for the management of collar rot was carried using contact, systemic and combi fungicides. Among contact fungicides tested Mancozeb showed cent per cent inhibition at 0.20 %. Among systemic fungicides tested Hexaconazole (0.05 %) and Propiconazole (0.15 %) showed cent per cent inhibition. Among the combi fungicides evaluated Carbendazim 12 % + Mancozeb 63 % (0.15 %) and Hexaconazole 4 % WP + Zineb 68 %, Carboxin 37.5 % + Thiram 37.5 %, Tricyclazole18 % + Mancozeb 62 % WP, Captan70 % + Hexaconazole 5 % WP at 0.05 per cent concentration showed cent per cent inhibition. Among allthe fungicides tested combi products were found to be effective (Hexaconazole 4 % + Zineb 68 % at 0.05 %) in inhibiting the pathogen.

Using a bio-economic farm model to evaluate the economic potential and pesticide load reduction of the greenRelease technology

CONTEXTPolicies and strategies at EU and national level aim at a reduced use of pesticides in agriculture, such as the Farm to Fork Strategy of the EU Commission. Technological progress can lower pesticide application and contribute to a sustainable bioeconomy. As an example, the greenRelease technology increases the attachment of the active ingredient of plant protection products to the leaf surface and slowly releases the active ingredient from a microgel container. Experiments under both controlled and field conditions have demonstrated the potential of the greenRelease technology to reduce pesticide use. As a so-called platform technology, the greenRelease concept can be applied to various crops and plant protection chemicals. OBJECTIVETo guide further development, this study analyses the greenRelease technology regarding its economic potential and its possible contribution to the reduction of environmental and health risks from pesticide use. METHODSTo do so, we use a bio-economic farm model to assess the technology potential for a typical farm and spraying sequences of various crops in northwestern Germany. RESULTS AND CONCLUSIONSThe results reveal that the economic potential of the greenRelease technology is highest for systemic fungicides in all assessed crops as well as for herbicides for potato cultivation. It is lowest for insecticides in winter barley and potato as well as for contact fungicides, due to the small doses and low product costs. The potential to lower possible environmental and health risks of pesticide use, indicated by the Danish pesticide load indicator, is highest for fungicides in potato, winter wheat, and winter barley as well as for herbicides in sugar beet cultivation. Relative to overall costs in arable farming, the cost changes induced by the greenRelease technology are minor, such that the environmental benefits will be key for promoting its application. However, the economic competitiveness of the technology increases if agri-environmental policies progressively internalize the negative externalities of pesticides use. SIGNIFICANCEThis research is the first comprehensive economic and environmental assessment of the technology greenRelease which can contribute to lower the environmental burden of pesticide use in agriculture.

Fungicides and bees: a review of exposure and risk.

Fungicides account for more than 35% of the global pesticide market and their use is predicted to increase in the future. While fungicides are commonly applied during bloom when bees are likely foraging on crops, whether real-world exposure to these chemicals - alone or in combination with other stressors - constitutes a threat to the health of bees is still the subject of great uncertainty. The first step in estimating the risks of exposure to fungicides for bees is to understand how and to what extent bees are exposed to these active ingredients. Here we review the current knowledge that exists about exposure to fungicides that bees experience in the field, and link quantitative data on exposure to acute and chronic risk of lethal endpoints for honey bees (Apis mellifera). From the 702 publications we screened, 76 studies contained quantitative data on residue detections in honey bee matrices, and a further 47 provided qualitative information about exposure for a range of bee taxa through various routes. We compiled data for 90 fungicides and metabolites that have been detected in honey, beebread, pollen, beeswax, and the bodies of honey bees. The risks posed to honey bees by fungicide residues was estimated through the EPA Risk Quotient (RQ) approach. Based on residue concentrations detected in honey and pollen/beebread, none of the reported fungicides exceeded the levels of concern (LOC) set by regulatory agencies for acute risk, while 3 and 12 fungicides exceeded the European Food Safety Authority (EFSA) chronic LOC for honey bees and wild bees, respectively. When considering exposure to all bees, fungicides of most concern include many broad-spectrum systemic fungicides, as well as the widely used broad-spectrum contact fungicide chlorothalonil. In addition to providing a detailed overview of the frequency and extent of fungicide residue detections in the bee environment, we identified important research gaps and suggest future directions to move towards a more comprehensive understanding and mitigation of the risks of exposure to fungicides for bees, including synergistic risks of co-exposure to fungicides and other pesticides or pathogens.

Management of Grape Powdery Mildew with an Intelligent Sprayer and Sulfur.

Wine grapes are an important agricultural commodity in the Pacific Northwest, where grape powdery mildew (GPM) is one of the main disease problems. The efficacy of various sulfur concentrations and output volumes from an air blast sprayer retrofitted with the Intelligent Spray System (ISS) were evaluated for the management of GPM. The ISS consists of a LiDAR sensor, Doppler speed sensor, embedded computer, flow controller, and individual pulse-width-modulation solenoid valves at each nozzle. GPM cluster severity ranged from 55 to 75% across all trials in the study when the ISS was used at its default spray rate of 62.5 ml/m3 with micronized sulfur at 6 g/liter, which was significantly higher than all other fungicide treatments but lower than nontreated controls. Similarly, leaf incidence values were highest on nontreated vines, followed by micronized sulfur at 6 g/liter applied at 62.5 ml/m3, with all other fungicide treatments being significantly lower in all trials. Using the ISS at the 62.5 ml/m3 rate and a rotation of locally systemic fungicides resulted in the lowest observed GPM leaf incidence and average cluster severity of 11% in both 2019 and 2020, the lowest cluster severity of all fungicide treatments tested. GPM control with the ISS and micronized sulfur was equivalent to a constant-rate air blast treatment at 6 g/liter when the spray rate of the ISS was increased to 125 ml/m3 or the concentration of sulfur was increased to 24 g/liter. In those cases, the amount of sulfur applied to vines was at or above the minimum label rate from bloom until the end of the season, or the entire season, respectively. This study has shown that sufficient disease control cannot always be expected when pesticides are mixed at the same rate as would be used for a constant-rate sprayer in a variable rate sprayer, especially when contact fungicides such as sulfur are used. With appropriate adjustments, the variable-rate ISS can be a useful tool to reduce pesticide quantities, water needed for mixing, and as a result labor, because fewer trips to refill for a given spray event are needed.

β-Glucan-Functionalized Mesoporous Silica Nanoparticles for Smart Control of Fungicide Release and Translocation in Plants.

In this work, an enzyme-responsive nanovehicle for improving captan (CAP) contact fungicide bioactivity and translocation in plant tissues was synthesized (CAP-MSNs-β-glucan) by attaching β-glucan to the outer surface of mesoporous silica nanoparticles. CAP-MSNs-β-glucan properties were tested by FTIR, ζ-potential, DLS, XRD, TGA, FE-SEM, and HR-TEM. Cargo protection ability of CAP-MSNs-β-glucan from photolysis and hydrolysis was examined in comparison to CAP commercial formulation (CAP-CF). CAP-MSNs-β-glucan distribution in plant tissues, bioactivity against Fusarium graminearum, and biotoxicity toward zebrafish (Danio rerio) were tested and compared with that of CAP-CF. CAP-MSNs-β-glucan results showed good loading efficacy reaching 18.39% and enzymatic-release dependency up to 83.8% of the total cargo after 20 days of β-glucan unsealing. CAP-MSNs-β-glucan showed significant release protection under pH changes. MSNs-β-glucan showed excellent CAP protection from UV. CAP-MSNs-β-glucan showed better distribution in corn tissues and 1.28 more inhibiting potency to Fusarium graminearum than CAP-CF. CAP-MSNs-β-glucan showed 1.88 times lower toxicity than CAP-CF to zebrafish after 96 h of treatment. We recommend using such formulations to overcome shortcomings of contact fungicides and achieve better and sustainable farming.

The Influence of Wetting Agent and Type of Nozzle on Copper Hydroxide Deposit on Sugar Beet Leaves (Beta vulgaris L.)

Protective fungicides are sensitive to environmental conditions such as rainfall and solar radiation. Therefore, it is important to prolong the biological activity and fungicide resistance to the above-mentioned factors that can be achieved by adding a wetting agent to the working solution. Additionally, the quality and efficiency of preventive contact fungicides significantly depend on the application technique. Thus, it is important to make the right choice of the nozzles and adjust the working parameters of the treatment. The aim of this work is to determine the influence of a wetting agent and type of nozzle on copper hydroxide (2 L ha−2) deposits on sugar beet leaves. Experiments are set up under laboratory and field conditions. A pinole-based wetting agent is applied at three rates (0.3, 0.6, and 1.0 L ha−1) and two types of nozzles are used (standard with flat jet and modern turbo-drop twin-jet). A brilliant blue tracer is added to a working solution to enable the measurement of copper hydroxide deposits. The deposit amount is recorded before and after the rain simulation (15 L m−2) with a spectrophotometer light beam. In order to ensure the timeliness of the application of fungicides, remote sensing of vegetative indices is used as an indicator of disease occurrence. The results indicated an increase in copper hydroxide deposits with the increase in wetting agent rates for both types of nozzles and in both laboratory and field experiments. Moreover, when applying the copper hydroxide mixtures with modern turbo drop nozzles, the increase in copper hydroxide deposit is significant, compared to the standard nozzles.

Human Health and Ecosystem Quality Benefits with Life Cycle Assessment Due to Fungicides Elimination in Agriculture

Industrial agriculture results in environmental burdens due to the overuse of fertilizers and pesticides. Fungicides is a class of pesticides whose application contributes (among others) to human toxicity and ecotoxicity. The European Union aims to increase organic agriculture. For this reason, this work aims to analyze climate change, freshwater ecotoxicity, terrestrial ecotoxicity, human toxicity, (terrestrial) acidification, and freshwater eutrophication impacts of fungicides and calculate expected benefits to human health (per European citizen) and ecosystem quality (terrestrial) with life cycle assessment (LCA) during crop production. The Scopus database was searched for LCA studies that considered the application of fungicides to specific crops. The analysis shows how many systemic and contact fungicides were considered by LCA studies and what was the applied dosage. Furthermore, it shows that fungicides highly contribute to freshwater ecotoxicity, terrestrial ecotoxicity, human toxicity, and freshwater eutrophication for fruits and vegetables, but to a low extent compared to all considered environmental impacts in the case of cereals and rapeseed. Expected benefits to human health and ecosystem quality after fungicides elimination are greater for fruits and vegetables, ranging between 0 to 47 min per European citizen in a year and 0 to 90 species per year, respectively.

Evaluation of fungicides and bacterial antagonists for management of Corynespora leaf spot on mungbean (Vigna radiata L. Wilczek)

To minimize losses likely to occur due to Corynespora leaf spot, systemic and contact fungicides and formulation of bacterial antagonists like Bacillus subtilis DTBS-5, B. amyloliquefaciens DSBA-11, and Pseudomonas fluorescens DTPF-3 talc-based formulations were evaluated to manage the disease. Though mancozeb has the lowest EC50 value of 1250.54 ppm it was not efficient in the field experiment. In addition, dual culture assay to determine the efficacy of bacterial antagonists against C. cassiicola, B. amyloliquefaciens DSBA-11 effectiovely reduced growth of C. cassiicola. In the field experiments conducted during Kharif 2019 and 2020, two sprays with Azoxystrobin 23 SC@ 0.5 ml lit−1 were found most effective in reducing disease severity by 57.7% and 67.7% respectively during Kharif 2019 and 2020. Azoxystrobin 23 SC treatment resulted in a maximum increase of 281.5 kg in grain yield followed by Pseudomonas fluorescens DTPF-3 264.7 kg and Bacillus subtilis DTBS-5 248.9 kg yield.

Strategy of potato chemical protection from diseases

During 2019-2021, the effectiveness of pre-planting treatment of potato tubers of the Sante variety against rhizoctonia disease and two schemes for the use of combined and contact fungicides in the conditions of the Moscow region was evaluated. The biological efficacy of the Idikum preparation for pre-planting treatment of tubers against rhizoctonia disease was 83.5%. All tested potato protection schemes during the growing season showed high efficiency in reducing the prevalence and degree of late blight and alternaria leaf spot. Depending on the prevailing weather conditions of the growing season, the scheme, where the contact-systemic preparation Metaxyl was used for the first treatment, provided an increase in yield by 36.3-47.5%, the second scheme – with the first treatment with the contact preparation Kumir – 25.8-36.3%.

A Study on the Effect of Soil and Sediment Types on the Fugacity Based Multimedia Partitioning of a Contact Fungicide Fluopyram: An Equilibrium Quality Criterion (EQC) Level 1 Approach

Equilibrium Quality Criterion (EQC) Level I calculations have been performed with Standard Equilibrium Quality Criterion (EQC) environment to study the environmental partitioning of a fungicide Fluopyram. Equilibrium Quality Criterion (EQC) Level I calculation assumes no degradation of the chemical, steady-state, and equilibrium conditions between the environmental compartments. The results reveal that the concentration of Fluopyram is expected to be maximum in the sediment compartment, followed by soil and water compartments. The effect of soil and sediment types on partitioning has been studied by systematically varying the densities of these two compartments. In the sediment compartment, the Fluopyram concentration is predicted to be highest if the sediment type is ‘sandy’ and the soil type is ‘clay’.

Management of Banana Black Sigatoka in Industrial Dessert Banana Cultivation through the Reasoned Use of Synthetic Fungicide VONDOZEB 62 OD

Black Sigatoka, caused by the fungus Mycosphaerella fijiensis, is the main devastating banana (Musa sp.) leaf disease. The environmental and health constraints linked to the misuse of chemicals against this disease imply efficient methods aimed at reducing these products. This study, conducted on the Akressi site of Société Agricole Kablan Joublin (SAKJ), an industrial company of dessert banana, assessed the reduction in the dose of contact fungicide associated with adjuvants on black Sigatoka prevalence in Ivorian industrial banana tree plantations. This study made it possible to assess certain phytopathological (YLA, YNL and SI), growth (NEL and LER) and toxicity parameters of treatments every week over two months. Banana trees treated with reduced doses of VONDOZEB 62 OD associated with adjuvants induced statistically identical performance to the reference control. Thus, the use of reduced doses of fungicides associated with adjuvants appears to be an ideal strategy for reducing M. fijiensis severity and the use of chemical fungicides in the control of this disease.

Impact of foliar application of fungicides on tomato leaf fungal community structure revealed by metagenomic analysis.

Fungicides are commonly used to manage plant pathogens. However, little is known about their effects on the non-target fungal communities that inhabit inside and outside the plant. These fungicides may have adverse effects on beneficial microbial communities with possible consequences for plant health and productivity. Hence, a metagenomic approach, based on the ITS2 region of fungal rDNA, was used to study the impact of foliar application of two fungicides (propineb and iprodione + carbendazim) on non-target tomato leaf fungal communities, in the context of early blight disease management. Metagenomic analysis revealed that the richness and diversity of tomato leaf fungal populations were adversely affected by the chemical treatments tested. Among the two fungicides, propineb (contact fungicide) imparted less non-targeted microorganisms than iprodione + carbendazim (systemic fungicide). In addition, all samples showed association of pathogenic genera Cladosporium, Corynespora, Pseudocercospora along with early blight pathogen Alternaria on tomato leaves that otherwise were undetected. Metagenomic studies also revealed a new mode of action for fungicides and bioagents besides their direct effect that is shifting the microbial community structure so that it provides greater resistance against the pathogen.

Management of premature leaf fall (Marssonina coronaria) of apple with new generation fungicides in the North‐Western Himalayan Region of India

AbstractIn the north‐western Himalayan region of India, premature leaf fall (PLF) caused by Marssonina coronaria is a major disease in apple orchards. Field experiments were conducted at a commercial orchard to evaluate the efficacy of new‐generation fungicides on PLF management during 2018 and 2019. Three contact fungicides (chlorothalonil, propineb and mancozeb), one systemic fungicide (difenoconazole) and four combination products (metiram +pyraclostrobin, fluxapyroxad +pyraclostrobin, tebuconazole +trifloxystrobin and fluopyram +tebuconazole) were evaluated against an untreated control (UTC) by applying them at three times at 15‐day intervals to trees of the susceptible apple cultivar ‘Royal Delicious’. Out of all tested treatments, tebuconazole +trifloxystrobin achieved the lowest area under disease progress curve (AUDPC) and the greatest yield increase. Similarly fluxapyroxad +pyraclostrobin and fluopyram +tebuconazole also significantly reduced AUDPC and enhanced yield relative to the UTC. Taking into account the cost of the tested products, tebuconazole +trifloxystrobin offered the best benefit‐cost ratio in both years, followed by fluxapyroxad +pyraclostrobin and fluopyram +tebuconazole. Based on these findings, the combination products tebuconazole +trifloxystrobin, fluxapyroxad +pyraclostrobin and fluopyram +tebuconazole can all be recommended to the farmers of the north‐western Himalayan region for PLF management.

In-vitro Efficacy of Fungicides against Rhizoctonia solani Causing Banded Leaf and Sheath Blight of Maize

An experiment was carried out to find out the in-vitro efficacy of systemic and contact fungicides against the pathogen of maize banded leaf and sheath blight (Rhizoctonia solani f. sp. sasakii) by using poisoned food technique. The present experiment was conducted in College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University, Umiam, Meghalaya for the evaluation of different fungicides against the pathogen R. solani f. sp. sasakii. Eight systemic (Carbendazim, Tebuconazole, Propiconazole, Myclobutanil, Azoxystrobin, Metalaxyl, Tricyclazole, Pyraclostrobin), three contact (Mancozeb, Captan and Chlorothalonil) and combination of systemic and contact fungicide (Carbendazim + Mancozeb) were used for the experiment with different concentrations. Among twelve fungicides, Carbendazim was found to be the most effective at concentration of 0.1 % with 95.96 % growth inhibition. Suimilarly, Metalaxyl at concentration of 0.28 % was found to be the least effective with growth inhibition of 55.55 %. The results showed significant differences between different fungicides to inhibit the growth of R. solani.

Assessment and Management of Tomato Diseases under Plastic House Conditions in Lamjung

An experiment was conducted under plastic houses at three farmers’ field, each farmer as a replication, in Tarku and Banhjakhet VDCs in Lamjung district during July to December 2010, to identify and manage major fungal diseases of tomato (variety Srijana) using chemicals and bio-pesticides. The treatments Bio-cure-F (Trichoderma viride, bio-fungicide), carbendazim (Bavistin, systemic fungicide) and Dithane M-45 (Mancozeb, contact fungicide) were applied as foliar spray. Control plot was maintained without application of any treatment. Mainly four fungal diseases, early blight (Alternaria solani), late blight (Phytophthora infestans), powdery mildew (Leveillula taurica) and septoria leaf spot (Septoria lycopersici) were recorded. Dithane M-45 appeared the best to control early blight, late blight and septoria leaf spot, followed by Bavistin and Bio-cure-F over control. Bavistin performed the best to control powdery mildew, followed by Dithane M-45 and Bio-cure F over control. Severity of fungal diseases appeared high on tomato in plastic house. Based on type of disease, Dithane M-45 or Bavistin is suggested to spray for the management.

The efficacy of washing strategies in the elimination of fungicide residues and the alterations on the quality of bell peppers

Food safety problems caused by pesticide residues in vegetables have become a top issue to raise public concern. In this study, bell peppers were grown in an experimental field and sprayed with two systemic (azoxystrobin and difenoconazole) and one contact (chlorothalonil) fungicides. Ozone (ozonated water and water continuously bubble with ozone) or conventional domestic (washing with distilled water, detergent, acetic acid, sodium bicarbonate, and sodium hypochlorite solutions) procedures were investigated to identify the most effective way to remove fungicide residues in bell peppers. The residues in the fruits and the washing solutions were determined by solid–liquid extraction with a low-temperature partition (SLE/LTP) and liquid–liquid extraction with a low-temperature partition (LLE/LTP), respectively, and analyzed by gas chromatography. Water continuously bubbled with ozone a concentration of 3 mg L-1 was the most efficient treatment with removal of fungicides residues ranging from 67% to 87%. However, similar treatment at a lower concentration (1 mg L-1) did not only efficiently removed fungicide residues (between 53% and 75%) but also preserving the quality of the fruit along a storage time of 13 days. Among the conventional solutions, sodium bicarbonate at 5% showed good efficiency removing between 60% and 81% of the fungicide residues from bell peppers, affecting the color quality of the fruit. Overall, the most affected physicochemical parameters in bell peppers after the treatments were weight loss, color, and vitamin C content.