Alternative Fungicide Research Articles

Chemical profile, thermodynamic stability and fungicidal activity of the nanoemulsion incorporated with essential oil and hydroalcoholic extract of Syzygium aromaticum (L.) Merr. & LM.Perry

.This work aimed to evaluate the fungicidal activity of nanoemulsions of hydroalcoholic extract and essential oil of sprouts of Syzygium aromaticum. For the extraction of essential oil, the hydrodistillation technique was used. To obtain the hydroalcoholic extract, the process of maceration with solvent extract methanol P.A 70% (v / v) was performed. Nanoemulsions were obtained using the low-energy phase inversion method. For the fungicidal activity, the Broth Dilution and Agar Seeding assay was used to determine the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (CFM). The action of the biotechnological product was tested against three strains of fungi Aspergillus niger, Colletotrichum gloeosporioides, Penicillium chrysogenum. For antifungal action of the essential oil nanoemulsion, the MIC obtained was 25 µg mL-1, 25 µg mL-1 and 50 µg mL-1against A. niger, C. gloeosporioides and P. chrysogenum, respectively, for the hydroalcoholic extract nanoemulsion the result was 50 µg mL-1, 50 µg mL-1 and 100 µg mL-1 for A. niger, C. gloeosporioides and P. chrysogenum, respectively. Finally, this study points to the nanoemulsion of S. aromaticum as an alternative fungicide in the control and combat of pathogenic fungi.

Application of plant-derived bioactive compounds as seed treatments to manage the rice pathogen Fusarium fujikuroi

Plant essential oils (EO) possess antifungal properties due to the presence of terpenoids and phenolics capable of damaging microbial cell membranes. The compounds present in EO could represent a valid alternative to synthetic fungicides in rice crop protection, especially in Europe, where the available plant protection products are increasingly scarce, particularly for managing seed-borne fungal pathogens like Fusarium fujikuroi Nirenberg, the causal agent of bakanae disease. Bakanae is a major concern in Europe for seed producers, which often fail to comply with the strict regulatory limits on the presence of the pathogen in the field, resulting in the rejection of the seed crop from marketing and economic losses. The present work was aimed at studying 1) the in vitro effect of EO derived compounds against F. fujikuroi and 2) their efficacy in disease management under field conditions applied as seed treatments. Results confirmed the in vitro antifungal activity of tested compounds: specifically, thymol (0.025% vol/vol), terpinen-4-ol (0.1%), and eugenol (0.05%) showed strong antifungal activity against all the tested F. fujikuroi strains. Two-years, two-locations open field trials showed that seeds treated with thymol (20%) and eugenol (5%) significantly reduced bakanae incidence compared to untreated control, without any phytotoxicity effect on rice seed. The efficacy of these two compounds in managing the disease without affecting germination rates was comparable to the commercially available prochloraz and triticonazole formulation, considered as the positive control. Our results suggest that thymol and eugenol could be used as alternative fungicides in innovative formulations for seed dressing, with the advantage of being compliant with the European IPM framework and organic farming legislation.

Essential oil of Noni, Morinda citrifolia L., fruits controls the rice stem-rot disease without detrimentally affect beneficial fungi and ladybeetles

The use of botanical fungicides has been presented as a promising tool to replace the use of synthetic compounds, as the former seems to offer reduced risks to the environment and human health. Here, we characterized the major constituents and evaluated the potential of essential oils of Noni, Morinda citrifolia L. plants for controlling stem-rot disease caused by the fungus Sclerotium rolfsii Catt in Neotropical rice, Oryza sativa L., fields. Using in silico molecular predictions and toxicological approaches, we further assessed the essential oil selectivity against beneficial organisms such as the fungi Trichoderma asperellum Samuels, Lieckfeldt & Nirenbeand the ladybeetles Eriopis connexa Germar and Coleomegilla maculata DeGeer. Our results revealed that octanoic acid (64.0 %), butanoic acid (10.2 %), and hexanoic acid (8.6 %) were the major oil components. When applied at 30 mg/mL, the essential oil inhibited mycelial growth, whereas at 10 mg/mL, it inhibited the germination of all S. rolfsii sclerotia. The essential oil application at 25 mg/mL reduced disease severity in both curative (56.4 %) and preventive (71.2 %) methods. Essential oil applications (30 mg/mL) did not affect the beneficial fungus T. asperellum nor did it kill any ladybeetle. Our molecular docking analyses reinforced the essential oil selectivity actions predicting higher potential interactions between its major components and the tyrosine-tRNA ligase of S. rolfsii compared to those of T. asperellum. Collectively, our findings demonstrated that Noni essential oil could control S. rolfsii infestations without causing any detrimental effects on relevant beneficial organisms, highlighting its potential as an alternative fungicide.

A review of application of natural products as fungicides for chili

Anthracnose disease in chillies is a serious problem for farmers. So far, synthetic fungicides have been used as solution for the treatment of this disease. However, the side effects of synthetic fungicides to public health and environment raised awareness on alternative fungicides derived from natural resources. This paper aims to review plants that are potential as an alternative to fungicides for chili plantation, fabrication of test solutions, in vitro and in vivo fungicide test. Many plants were investigated as alternatives to plant-based fungicide. The utilization of leaves as samples including rhizomes, roots, tubers, weevils, seeds, fruit, flowers and other parts of the plant. The extract fabrication method used as a fungicide test include: maceration method, gradual fractionation method, and decoction method. The maceration method is the method most widely used to extract fungicidal active compounds from plants. Some studies that carried out in vitro tests were unable to compare with synthetic fungicides so it was not possible to determine their effectiveness for plant-based fungicide for chillies when compared to synthetic fungicides. In vitro Extract of 80% alcohol and 10%/60% n-hexane of pacar cina (Aglaia odorata L.) leaves can be compared with the performance of propineb 0.2%. In addition, the 60% and 70% kirinyuh (Chromolaena odorata L.) leaf extracts were also able to match Acrobat 0.2% performance in vitro. Based on the in vivo test, suren (Toona sureni Merr) leaf extract and nut bulbs can be used as an alternative to vegetable / natural fungicides to help overcome the problem of anthracnose in chilies.

Evaluating Fungicide Selections to Manage Pythium Root Rot on Poinsettia Cultivars with Varying Levels of Partial Resistance.

Pythium aphanidermatum is the predominant species causing Pythium root rot of commercially grown poinsettia (Euphorbia pulcherrima Willd. ex Kotzch) in North Carolina. Pythium root rot is managed primarily through a combination of sanitation practices and preventative fungicide applications of mefenoxam or etridiazole. Insensitivity to mefenoxam is common but growers continue to rely on it from lack of inexpensive and efficacious alternatives. This research was conducted to identify alternative fungicides for Pythium root rot control and to evaluate their efficacy on poinsettia cultivars with varying levels of partial resistance. Greenhouse studies were conducted to assess efficacy of fungicide treatments in seven poinsettia cultivars inoculated with a mefenoxam-sensitive isolate of P. aphanidermatum. One study examined control with a single fungicide drench made at transplant and a second study examined repeat fungicide applications made throughout the experiment. Treatments containing etridiazole, mefenoxam, fenamidone, and cyazofamid provided control of Pythium root rot across all cultivars in both experiments whereas Fosetyl-al, potassium phosphite, and Trichoderma spp. failed to offer satisfactory control. Azoxystrobin, pyraclostrobin, and propamocarb reduced disease on some cultivars but failed to control Pythium root rot on highly susceptible cultivars. Four isolates of P. aphanidermatum cultured from plants growing in commercial greenhouses were evaluated for in vitro sensitivity to fungicides labeled for Pythium root rot control at four rates. Etridiazole, fosetyl-al, and potassium phosphite completely inhibited mycelial growth, whereas isolates varied in response to mefenoxam, cyazofamid, propamocarb, fenamidone, azoxystrobin, and pyraclostrobin in vitro. Twenty-one additional isolates then were evaluated at label rates of these fungicides. Seven isolates were insensitive to label rates of all three quinone outside inhibitors and one isolate was insensitive to the quinone outside inhibitors and mefenoxam. These results provide guidelines for selecting fungicides to maximize control of Pythium root rot on poinsettia cultivars.

Antifungal effect of some plant extracts and their combination with Moncut fungicide on sugar beet root rot

Sugar beet (Beta vulgaris L. Chenopodiaceae) has become the first Egyptian crop for sugar production because it contributed with 59.5% of total sugar production. Sclerotium rolfsii is a soil-borne plant pathogenic fungi incident of southern sclerotium rot in sugar beet. The aim of the present study was to investigate the effect of some plant extracts in different solvents as inhibitory control agents against the growth plant pathogen S. rolfsii. Five plant extracts; Roselle, pomegranate, rosemary, black pepper and chamomile were evaluated as inhibitors for Sclerotium rolfsii of sugar beet root rot under laboratory and greenhouse conditions during 2016/2017 growing season at Gemmeiza Agricultural Research Station, (ARC). The results indicated that all tested plant extracts caused remarkable growth inhibition of S. rolfsii compared with control. However, black pepper extract was the most effective against S. rolfsii (recorded 93.33% inhibition). On the other hand, Pomegranate extract in methanol solvent showed also high inhibition percentage (93.30%). All plant extracts mixed with Moncut fungicides demonstrated an antagonistic effect. The pomegranate and black pepper treatments showed the lowest disease severity compared with control. Furthermore, the pomegranate and black paper treatments recorded the highest root weight, root yield/plot, total soluble solids percentage and sucrose content. Also, pomegranate and black pepper treatments reflected the highest amount of total phenols, free phenols, and conjugated phenols. Additionally, the interaction of pomegranate and black pepper treatments with S. rolfsii pathogen, showed the highest activity of oxidative enzymes peroxidase and polyphenol oxidase. This study recommends the application of pomegranate and black pepper as natural alternative fungicides against Sclerotium rolfsii plant infection.

Evaluating the efficacy of osthole and matrine for control of Sorghum purple spot

Osthole is a coumarin compound extracted from the canopy flower of the umbelliferae. Matrine, whose main components are alkaloids and flavonoids, was extracted from the roots, stems, leaves and fruits of Sophora flavescens by ethanol or other organic solvents. In this study, the efficacy of the combined biological agents matrine and osthole against Sorghum purple spot caused by Cercospora sorghi was conducted by laboratory, greenhouse and field experiments. The results from petridish assay showed that the inhibitory effect of the mixture of osthole and matrine against C. sorghi was better than osthole or matrine alone or Zineb, and the best mixing ratio of osthole to matrine was 1:2. In greenhouse experiment, the efficacy of 25 μg/mL of matrine · osthole against Sorghum purple spot was similar to Zineb. Field experiment showed that the efficacy of 25 μg/mL of matrine · osthole on Sorghum purple spot reached 68.4% on the 30th day. These results suggested that the combined matrine and osthole had a good effect and could be used as an alternative fungicide against Sorghum purple spot.

Botanical and chemical fungicides in the treatment of commercial seeds of Brachiaria brizantha and Panicum maximum

Brazil is the largest producer, consumer, and exporter of forage seeds in the world. However, the high incidence of pathogens threatens the seed production system, resulting in decreases in production and quality. Currently, the emphasis has been placed on the use of alternative products as a way of maintaining productivity and environmental sustainability. Thus, the objective of this study was to evaluate the mycoflora associated with the commercial seeds of Brachiaria brizantha and Panicum maximum treated with chemical and alternative fungicide. To test with chemical and alternative treatments, seeds were subjected to fluazinam + thiophanate-methyl, fludioxonil + metalaxyl-M, noni essential oil, rosemary pepper essential oil, sulfuric acid. There was also an untreated control. The most efficient products in the control of incident fungi were, in decreasing order, fluazinam + thiophanate-methyl, fludioxonil + metalaxyl-M, noni essential oil, rosemary pepper essential oil, and sulfuric acid. Fungicides mainly controlled the genera Alternaria, Aspergillus, Bipolaris, Chaetomium, Cladosporium, Colletotrichum, Curvularia, Fusarium, Penicillium, Phoma and Rhizopus. Essential oils showed positive effects in controllingBipolaris, Curvularia, and Fusarium. Sulfuric acid reduced the incidence of Bipolaris, Colletotrichum, Curvularia, Fusarium, Phoma, and Rhizopus. Seed treatment is one of the promising strategies for obtaining seeds of a healthy quality. As a result, the fungicides and botanical components listed above were promising in reducing fungi associated with forage seeds and can be used for seed treatments and in the development of new products with a natural base through essential oils.

Verification of Comet Plus 475 G/L EC Fungicide Against Wheat Stripe Rust (<i>Puccinia striiformis</i> f.sp. <i>tritici</i>) Disease on Bread Wheat in Bale, Southeastern Ethiopia

Wheat (<i>Triticum aestivum</i> L.) is the most widely cultivated crops in Ethiopia. However, wheat production is very low due to many factors. Of these, disease like stripe rust of wheat is the main constrained biotic factor and cause great yield losses. The field experiment was conducted at three hot-spot locations of wheat rust diseases in the zone namely; Sinana, Selka, and Agarfa during the 2019 cropping season to evaluate the effectiveness of newly introduced fungicide for the management of yellow rust disease of wheat. Variety Kubsa, which is susceptible to the three wheat rusts were used. The trial was laid out at three locations with non-replicated plots. Two systemic fungicides (Comet plus and Rex®Duo) and untreated plot (control) were used as a treatment. A significant difference (P<0.05) was observed between fungicide treatments and unsprayed plots on yellow rust severity, grain yield, thousand kernel weight, and hectoliter. Based on field observation and analyzed data results revealed that the newly introduced fungicide found to be effective in controlling stripe rust of wheat. Thus, Comet plus 475 G/L EC is recommended as an alternative fungicide for the management of stripe rust of wheat in wheat-growing areas of the country.

Reducing Chlorothalonil Use in Fungicide Spray Programs for Powdery Mildew, Anthracnose, and Gummy Stem Blight in Melons.

Fungicides are applied to nearly 80% of U.S. melon acreage to manage the numerous foliar and fruit diseases that threaten yield. Chlorothalonil is the most widely used fungicide but has been associated with negative effects on human and bee health. We designed alternative fungicide programs to examine the impact of reducing chlorothalonil use (Bravo Weather Stik) on watermelon, cantaloupe, and honeydew melon in 2016, 2017, and 2018 in Maryland. Chlorothalonil was replaced in the tank mix of weekly sprays of targeted fungicides with either polyoxin D zinc salt (Oso) or an extract of Reynoutria sachalinensis (Regalia). Powdery mildew (PM; Podosphaera xanthii), gummy stem blight (GSB; Stagonosporopsis spp.), and anthracnose (Colletotrichum orbiculare) were the most prevalent diseases to occur in the 3 years. Replacing chlorothalonil with the biopesticides as the tank-mix component of the fungicide spray program was successful in reducing GSB and PM severity in cantaloupe, honeydew melon, and watermelon compared with the untreated control, with the exception of GSB in 2017 in cantaloupe, and similar to the program including chlorothalonil in all cases, except anthracnose in watermelon. Anthracnose disease severity was not significantly reduced compared with the untreated control when chlorothalonil was replaced with the biopesticides and yields were not improved over the chlorothalonil-alone treatment in any of the trials. Therefore, replacement of chlorothalonil may not fully address its loss as a fungicide resistance management tool but efficacy can be maintained when polyoxin D is alternated with R. sachalinensis as a tank mix with targeted fungicides to manage PM and GSB.

Baseline sensitivity and resistance risk assessment of Valsa mali to pyraclostrobin

Pyraclostrobin, a quinone outside inhibitor (QoI) fungicide, has been registered to control apple tree Valsa canker (AVC) caused by Valsa mali in China. However, there is no data available regarding the resistance risk of V. mali to pyraclostrobin. In this study, the sensitivities of 120 V. mali isolates to pyraclostrobin were detected. The isolates were collected from apple orchards with no application of pyraclostrob at six provinces in China during 2013–2015, and showed similar sensitivity to pyraclostrobin. The EC50 values of these 120 V. mali isolates to pyraclostrobin ranged from 0.0014 to 0.0240 μg/mL, indicating an excellent inhibitory efficacy of pyraclostrobin to the pathogen. The EC50 values were distributed as a unimodal curve with a mean value of 0.0091 μg/mL, and the mean EC50 displayed correlation with geographic location. Meanwhile, three pyraclostrobin-resistant mutants (PR mutants) of V. mali were obtained using fungicide adaption method, with a resistance factor (RF) of 41.0, 56.8 and 22.0, respectively. The mutants showed a stable resistance to pyraclostrobin after 10 transfers on pyraclostrobin-free medium. Comparing with the corresponding parental isolates, the hyphal growth, mycelial dry weight and pathogenicity of PR mutants were significantly reduced, but the number of propagules showed no significant difference. More importantly, no cross-resistance of PR mutants to pyraclostrobin, tebuconazole, difenoconazole, imazalil and thiophanate-methyl was detected. In conclusion, V. mali showed a moderate risk to pyraclostrobin, and pyraclostrobin could be used as an alternative fungicide to control AVC in the field in China.

Efficacy and Baseline Sensitivity of Succinate-Dehydrogenase-Inhibitor Fungicides for Management of Colletotrichum Crown Rot of Strawberry.

The current management of Colletotrichum crown rot (CCR) of strawberry, caused by Colletotrichum gloeosporioides sensu lato, relies on the use of a few fungicide classes, particularly QoI fungicides. Since resistance to QoI fungicides has recently been detected, alternative fungicide groups are needed to control this disease. Our objective was to evaluate the efficacy of succinate-dehydrogenase-inhibitor (SDHI) fungicides in managing CCR. Five SDHI fungicides, fluopyram, isofetamid, penthiopyrad, fluxapyroxad, and benzovindiflupyr, were applied 2 days before or 1 day after inoculation of cultivar Strawberry Festival. SDHI treatments were compared with the most common fungicides used for CCR management, i.e., thiophanate-methyl, pyraclostrobin, and captan. Benzovindiflupyr applied 1 day after inoculation was effective in reducing plant mortality and disease development. The baseline sensitivity of C. gloeosporioides isolates was determined in vitro using a spiral gradient dilution assay. The EC50 for benzovindiflupyr and penthiopyrad varied from 0.08 to 1.11 and 0.45 to 3.17 µg/ml, respectively, whereas the other SDHI fungicides did not inhibit fungal growth. If registered, benzovindiflupyr could serve as an alternative to manage CCR in Florida.

Potensi Ekstrak Lengkuas (Alpinia Purpurata K. Schum) Sebagai Fungisida Terhadap Jamur Alternaria Sp. Pada Tanaman Jeruk

Alternaria sp. is one the causess of diseases that attack citrus crops. Pest and diseases control efforts by farmers more often use pesticide synthesis. This study aims to determine the inhibition of mushroom growth and other benefits of galangal extract as a natural fungicide and determine the optimum concentration of galangan extract inhibiting the growth mushroom of Alternaria sp.. The method used was experimental, testing conducted by growing mycelium mushroom Alternaria sp. on a PDA that has been mixed with extract of galangal in according to the respective concentrations and analyze growth response by measuring the diameter. The best results indicated by the treatments 60% that control the growth of mushrooms with deaths amounted to 79%. This shown that galangal extract is able to control the growth of Alternaria sp. at concentrations 60% compared to a concentration of 20%, 30%, 40% and 50% because the active compounds at concentrations that are 60% higher, so galangal extract diffuse into the cell the growing of mushrooms and may cause disruption the growth mushrooms Alternaria sp.. The higher concentration of extract given, the ability to controlling the growth mushroom of Alternaria sp. the better. The utilization of galangal material is done as an alternative fungicide in the control of plant diseases that are eco friendly.

Using Alternative Fungicides and Fertilizers for Management Root Rot and Wilt Diseases and Their Effect on Productivity of Rosemary Plant

Using Alternative Fungicides and Fertilizers for Management Root Rot and Wilt Diseases and Their Effect on Productivity of Rosemary Plant

Alternative Products to Control Soybean Downy Mildew in the Field

Soybean mildew caused by Oomycota Peronospora manshurica, is a disease widely spread in Brazil. In order to study the efficiency of soybean mildew control due to the application of alternative products and fungicide in the field, experiments were conducted in Ponta Grossa, PR, Brazil, during the 2013/2014 and 2014/2015 growing seasons. The design used was randomized blocks with four replications. The treatments were: 1-witness; 2-acibenzolar-S-methyl; 3-calcium; 4-micronutrients: copper, manganese and zinc; 5-micronutrients: manganese, zinc and molybdenum; 6-NK fertilizer; 7-Ascophyllum nodosum and 8-azoxystrobin + cyproconazole with the addition of Nimbus adjuvant. Four applications of alternative products (phenological stages V3, V6, R1 and R5.1) and two of fungicide (phenological stages R1 and R5.1) were performed. The mildew severity was estimated using a diagrammatic scale. The severity data made it possible to calculate the area under the disease progress curve (AUDPC). In the 2014/2015 harvest the disease was more severe. The control of downy mildew by the use of fungicide did not reduce the epidemic. The fungicide was not efficient in the two evaluated seasons. All tested alternative products reduced the disease severity and AUDPC in both seasons. The best results in reducing downy mildew were found with the application of acibenzolar-S-methyl, micronutrients (Cu, Mn, Zn) and A. nodosum.

Transcriptome and cell wall degrading enzyme-related gene analysis of Pestalotiopsis neglecta in response to sodium pheophorbide a

Sodium pheophorbide a (SPA) is a new alternative fungicide with low toxicity and high efficiency, which has high fungicidal activity against Pestalotiopsis neglecta, a pathogen that causes black spot needle blight of Pinus sylvestris var. mongolica. To utilize SPA for plant disease control, understanding its antifungal mechanism is essential. Six cDNA libraries were constructed from 3 d-old P. neglecta mycelia (three SPA-infected and three untreated groups) and 29,850 expressed genes were obtained by Illumina HiSeq4000 sequencing. Compared with controls, 3268 differentially expressed genes (DEGs) were identified in SPA-treated groups, including 1879 upregulated and 1389 downregulated genes. Most DEGs were involved in the metabolism of amino acids, carbohydrates, and lipids, as well as cell structure and genetic information processing. These findings were further confirmed by decreased conductivity, RNA and protein content, and activities of nicotinamide adenine dinucleotide-dependent malate dehydrogenase, citrate synthase, isocitrate dehydrogenase, and succinate dehydrogenase. Moreover, qRT-PCR verified the reliability of the transcriptome results. After treatment with SPA at different concentrations for 60 min, the expressions of three cell wall degrading enzyme-related genes (PnEG, PnBG, and PnPG) were all suppressed. Overall, this study provided insights into the molecular mechanisms through which SPA inhibits P. neglecta, increasing the possibility of developing SPA into an effective fungicide in the future.

Alternative products on Asian soybean rust control and their influence on defoliation, productivity and yield components

ABSTRACT To study the efficiency of Asian soybean rust (Phakopsora pachyrhizi) control and to test the effects of using alternative products and fungicides, two field experiments were conducted during the harvest seasons 2013/2014 and 2014/2015. Treatments for the experiments were: 1- control (water); 2- acibenzolar-S-methyl; 3- calcium; 4- micronutrients: copper, manganese and zinc; 5- micronutrients: manganese, zinc and molybdenum; 6- NK fertilizer; 7- Ascophyllum nodosum, and 8- azoxystrobin + cyproconazole. The evaluated variables were: Asian soybean rust severity, defoliation, productivity and yield components. Based on severity data, the area under the disease progress curve was calculated. In the two experiments, the alternative products had no effect on Asian soybean rust or defoliation. Only the treatment with fungicide controlled the disease and decreased defoliation. The yield component affected by the treatments was the number of pods per plant, in both harvest seasons. Treatment with the fungicide protected soybean from yield loss in both experiments. Defoliation was strongly correlated with the weight of one thousand seeds and the number of pods per plant, emphasizing the importance of maintaining the leaf area to ensure the maintenance of the yield components in soybean crop.

Impact of Chemical and Alternative Fungicides Applied to Grapevine cv Nebbiolo on Microbial Ecology and Chemical-Physical Grape Characteristics at Harvest.

Viticulture is a cropping system in which treatment against fungal diseases (in particular powdery and downy mildews) can be extremely frequent. Accordingly, a reduction in antimicrobial treatments and the application of environmentally-friendly compounds are becoming increasingly important for a more sustainable viticulture. In addition to their effect against pathogens, the impact of these products on the quality of the grapes is very important for the oenological industries, but unfortunately at present few data are available. We evaluated the effect of the application of biocontrol products and resistance inducers in the vineyard on the mechanical properties, microbial ecology, technological and phenolic maturity of Vitis vinifera “Nebbiolo” grapes at harvest. The yield and vigor of vines were not influenced by the treatments, nor were the production of primary and secondary metabolites. However, the active ingredients influenced the mechanical properties of the skin (hardness and thickness). A significant hardening of the skin was detected when laminarin and chito-oligosaccharides were used, and sulfur induced a thickening of the skin with potential consequences for wine quality. Furthermore, the yeast community present on grape berries was influenced by the treatments. The abundance of Aureobasidium pullulans, the dominant species on the grape berry, changed in response to the compounds used. In addition, Alternaria sp. was reduced in some treatments with a potentially positive effect on the quality and the safety of the grapes. This study provides an overview of the effect of biocontrol products and resistance inducers on microbial ecology and “Nebbiolo” grape quality, contributing to the establishment of more sustainable and effective defense strategies in viticulture.

Anti-saprolegnia potency of some plant extracts against Saprolegnia diclina, the causative agent of saprolengiasis.

Saprolegnosis of fresh water fishes caused by Saprolegnia diclina often results in serious economic losses to fish hatcheries. Despite the proven efficiency of malachite green as a potential fungicide in prevention and control of fish saprolegnosis, there is a strong debate about its safety aspects in use since it was documented to be responsible for many carcinogenic and teratogenic attributes. Bioactivity of four ethanolic plant extracts were assessed to attain a natural alternative to the traditional fungicide currently used in saprolegnosis control. Ethanolic extracts of Punica granatum and Thymus vulgaris exhibited a potential efficacy in suppressing mycelial growth of S. diclina at concentration of 0.5 mg/ml while extracts of Nigella sativa and Zingiber officinales were not effective respectively. The extract of pomegranate showed the highest antifungal potency with minimum inhibitory concentration (MIC) of 200 ppm while thyme extract was less effective and recorded MIC of 400 ppm against S. diclina. The acute fish toxicity of the plant extracts indicated the low toxicity of P. granatum and T. vulgaris extracts as no fish mortalities were detected at aquaria containing 200, 400 and 800 ppm of plant extracts respectively. Considering the low toxicity of these plant extracts, it may be concluded that 200 and 400 ppm of pomegranate and thyme extracts which suppressed the mycelial growth of the S. diclina could be safely used for saprolegniasis control.Both of pomegranate and thyme extracts which proved to possess a potential antifungal activity can be considered as a natural alternative fungicides to control saprolegniasis avoiding carcinogenic malachite green application.

The potential use of the Penicillium chrysogenum antifungal protein PAF, the designed variant PAFopt and its γ-core peptide Pγopt in plant protection.

SummaryThe prevention of enormous crop losses caused by pesticide‐resistant fungi is a serious challenge in agriculture. Application of alternative fungicides, such as antifungal proteins and peptides, provides a promising basis to overcome this problem; however, their direct use in fields suffers limitations, such as high cost of production, low stability, narrow antifungal spectrum and toxicity on plant or mammalian cells. Recently, we demonstrated that a Penicillium chrysogenum‐based expression system provides a feasible tool for economic production of P. chrysogenum antifungal protein (PAF) and a rational designed variant (PAFopt), in which the evolutionary conserved γ‐core motif was modified to increase antifungal activity. In the present study, we report for the first time that γ‐core modulation influences the antifungal spectrum and efficacy of PAF against important plant pathogenic ascomycetes, and the synthetic γ‐core peptide Pγopt, a derivative of PAFopt, is antifungal active against these pathogens in vitro. Finally, we proved the protective potential of PAF against Botrytis cinerea infection in tomato plant leaves. The lack of any toxic effects on mammalian cells and plant seedlings, as well as the high tolerance to harsh environmental conditions and proteolytic degradation further strengthen our concept for applicability of these proteins and peptide in agriculture.