Postharvest Fungi Research Articles

Design and synthesis aldehydes-thiourea and thiazolyl hydrazine derivatives as promising antifungal agents against Monilinia fructicola.

Fungal diseases present a significant threat to global agriculture, necessitating the development of new, safe, and effective fungicides. Existing fungicides face resistance and health risks, prompting the synthesis of novel compounds. Researchers have synthesized aldehyde-based thiourea and thiazolyl hydrazine derivatives, evaluating their antifungal activities to identify impactful pesticide molecules. The results showed that most of the compounds had broad-spectrum antifungal activity against six plant pathogenic fungi and four post-harvest fungi. Notably, compound LN18 showed the best antifungal activity against Monilinia fructicola with a half-maximal effective concentration (EC50) of 0.17 μg mL-1, which was better than the commercial fungicide natamycin. A structure-activity relationship (SAR) study showed that the presence of unsaturated double bonds in the structure and the length of the carbon chain were the main factors affecting antifungal activity. The presence of unsaturated double bonds and an increase in the length of the carbon chain greatly improved inhibitory activity against the tested pathogens. The preliminary mechanism study showed that LN18 could damage the integrity of the mycelial plasma membrane, leading to leakage of intracellular nucleic acid and protein. LN18 also induced an increase in the intracellular reactive oxygen species level to exert its antifungal effects. In addition, compound LN18 had a stronger antifungal effect in vivo, and better phytotoxicity than natamycin, indicating broad application prospects in agriculture. Aldehydes-thiourea and thiazolyl hydrazine derivatives demonstrate remarkable antifungal efficacy against plant pathogenic and post-harvest fungi, offering a promising avenue for commercialization as highly efficacious, cost-effective and safe antifungal agents. © 2024 Society of Chemical Industry.

ERRATUM: Antifungal Potential of Selected Plant Extracts on Pathogenic Post-Harvest Fungi Causing Tuber Rot in Ipomoea batatas (L.) Lam. (Sweet Potato)

ERRATUM: Antifungal Potential of Selected Plant Extracts on Pathogenic Post-Harvest Fungi Causing Tuber Rot in Ipomoea batatas (L.) Lam. (Sweet Potato)

Antifungal Potential of Selected Plant Extracts on Pathogenic Post-Harvest Fungi Causing Tuber Rot in Ipomoea batatas (L.) Lam. (Sweet Potato)

Antifungal Potential of Selected Plant Extracts on Pathogenic Post-Harvest Fungi Causing Tuber Rot in Ipomoea batatas (L.) Lam. (Sweet Potato)

Harnessing Cold Plasma: An Innovative Strategy for Managing Postharvest Fungal Infections in Plants

Researchers in plant pathology in recent times; have faced obstacles in finding chemical-free methods to combat postharvest fungal infections on a large scale. While conventional approaches like heat treatments have been utilized, they often present drawbacks such as altering food quality or causing harm to the environment. An encouraging alternative is a cold plasma, which consists of a blend of gas-derived atoms, excited molecules, and charged particles. Unlike alternative treatments, cold plasma has demonstrated no adverse effects on fresh produce or the environment. This review delves into the potential of cold plasma technology in managing postharvest fungal diseases, offering insights into plasma generation systems and examining both in vivo and in vitro studies. By evaluating the benefits, constraints, and current research gaps, this review seeks to guide for implementation of cold plasma technology in commercial settings.

The Response of Naturally Based Coatings and Citrus Fungicides to the Development of Four Postharvest Fungi.

The tomato (Licopersicon esculentum Mill.) is considered to be one of the products with the highest demand due to its nutritional value; however, it is susceptible to infection by fungi during its pre- and postharvest stages. In this research, three commercial products (1% Citrocover, 1% Citro 80, and 0.002% Microdyn) and two coatings based on 1.0% chitosan/0.1% lime or 0.1% orange essential oils were evaluated in vitro and on Saladette tomatoes that were previously inoculated with four postharvest fungi. The application of the commercial citrus-based product Citrocover was highly effective in reducing the in vitro development of Aspergillus flavus, Fusarium oxysporum, and Colletotrichum gloeosporioides, but not Rhizopus stolonifer. The sanitizer Microdyn promoted infections with most fungi. Citrus-based products were effective in reducing infections with A. flavus in the tomatoes during storage. Overall, mycotoxin production was very low for all treatments. The use of commercial citrus-based products and coatings did not alter the weight loss, firmness, or total soluble solid contents of the treated tomatoes. The changes observed were, rather, associated with the normal ripening process of Saladette tomatoes. The commercial citrus-based products satisfactorily controlled the in vitro growth of the fungi Aspergillus flavus, Fusarium oxysporum, and Colletotrichum gloeosporioides.

Antagonistic Activity of Macrolepiota sp. CS185 against Post-Harvest Fungi of Fig Fruits (Ficus carica L.)

Macrolepiota sp. CS185 is a basidiomycete with high potential as a biocontrol agent against various phytopathogenic fungi. Regardless of its pronounced potential as a post-harvest fungi biocontrol agent, its activity in tomato seedlings infected with Alternaria alternata has not been well studied. Thus, the present work aimed to evaluate the cultures and supernatants’ antagonistic activity against fig fruits’ post-harvest fungi and antifungal activity production kinetics. The culture antagonistic characteristics were assessed through multiple confrontations, the supernatant concentration effect, and the kinetics of antagonistic action. The multiple confrontations showed differences (p ≤ 0.05) among phytopathogens and over time, with Colletotrichum sp. 2 being the most susceptible. Based on the 9-day incubation profile, the treatment fractions supplemented with a 50% concentration of Macrolepiota sp. CS185 supernatants showed a higher inhibition percentage (%In). Except for Alternaria alternata 1 and 2, the rest of the isolates showed a similar decrease in antagonistic activity up to a certain extent over time. Among all tested strains, Colletotrichum sp. 2 was found with a higher susceptibility. Regarding the production kinetics of antagonistic activity, a triple interaction was observed between the phytopathogen, the age of the Macrolepiota sp. CS 185 culture, and incubation time. In addition, changes in the mycelium growth rate (p ≤ 0.05) along with the higher activity in the supernatants of 20 and 30 days were observed and suggested the production of multiple bioactive metabolites. These results indicate that Macrolepiota sp. CS185 produces antifungal metabolites at different times and could be a suitable candidate to control fig fruits’ post-harvest fungi issues.

Essential oils from Mediterranean aromatic plants Artemisia herba-alba, Artemisia absinthium and Mentha longifolia to improve blueberry shelf life

The Mediterranean Basin is particularly rich in aromatic plants with essential oils whose composition and properties are still to be investigated. The aims of this work were to: investigate the chemical composition of essential oils from three typical Spanish aromatic species: Artemisia herba-alba, Artemisia absinthium and Mentha longifolia; evaluate the antifungal potential of essential oils against seven plant pathogenic and postharvest fungi; analyse the effectiveness of the Mentha longifolia essential oil in extending the blueberry fruit shelf life. The main compounds for the Artemisia herba-alba essential oil were camphor (29.8%), trans-thujone (22%), 1,8-cineole (14.5%) and cis-thujone (10.8%). In the A. absithium essential oil, they were cis-cryshanthemyl acetate (35.4%), cis-β-epoxiocimene (36%) and trans-β-epoxiocimene (10.4%). α-Terpineol acetate (32.6%), pulegone (14.2%) and 8-acetoxy carvotanacetone (10.3%) were the most important molecules in the obtained composition of the Mentha longifolia essential oil. Different bioassays were performed at the 300 μg/mL and 600 μg/mL doses using the distinct essential oils in potato dextrose agar culture medium. The Artemisia herba-alba and Artemisia absinthium essential oils at 300 μg/mL were not very effective. The Mentha longifolia essential oil strongly inhibited mycelial growth at the two tested doses, but it totally inhibited the growth of Curvularia hawaiiensis, Fusarium nygamai and Verticilliun dahliae at 600 μg/mL. The blueberries coated with the Mentha longifolia essential oil solution obtained a statistically higher percentage of healthy fruit than the control. They could be considered an ecofriendly alternative for postharvest treatment, and for maintaining the quality and turgidity of these berries during storage.

Prevalence of mycotoxins from silage in a small beef cattle feedlot over a storage season: a case study

Challenges exist worldwide for the storage of animal feed, though year-long feeding of livestock is especially difficult in northern climates, including Canada. Usage of silage allows for crops to be harvested at the optimal nutritional value and stored for extended periods in customized storage systems. This case study investigated various feed management practices typical of small beef cattle feedlot farms in Southwestern Ontario, Canada. Crop samples were collected monthly and analyzed for mycotoxins and fungal secondary metabolites by liquid chromatography mass spectrometry (LC-MS/MS). Stored barley contained modest concentrations of deoxynivalenol and related compounds, as well as near trace amounts of fumonisin. Stored hay contained low concentrations of deoxynivalenol and beauvericin from the field. Hot spots of the Penicillium metabolite citrinin were detected after 7–8 months of storage in barley (39.2 ng g−1). Citrinin was also detected after 7–8 months in hay (16.3–17.5 ng g−1) along with the appearance of trace amounts of other storage toxins, including penitrem A (8.84 ng g−1), griseofulvin (34.8 ng g−1) and sterigmatocystin (14.1–261 ng g−1). This case study was a unique opportunity to use ‘citizen science’ to observe the onset of postharvest fungi and associated mycotoxins in various storage conditions allowing for the farmer to make necessary modifications before major problems begin. An improved understanding of the storage conditions that foster fungal growth and mycotoxin production in this working farm led to better agronomic practices, ultimately improving feed quality, livestock health, and profitability.

Antifungal Activity of Thirty Essential Oils to Control Pathogenic Fungi of Postharvest Decay.

Essential oils (EOs) extracted from aromatic or medicinal plants are biodegradable, safe, and regarded as alternatives to chemical pesticides to reduce fungal species attacking different crops. In this study, thirty EOs at 0.5 mg/mL were evaluated for in vitro growth inhibition of the main postharvest fungi, which are Alternaria alternata, Botrytis cinerea, and Penicillium italicum. Cinnamomum verrum EO completely inhibited the mycelial growth of A. alternata and B. cinerea, and Syzygium aromaticum EO completely inhibited the mycelia of A. alternata. B. cinerea mycelial growth was completely inhibited by Gautheria fragrantissima, Cymbopogon nardus, Pelargonium asperum, and Cupressus sempervirens EOs. G. fragrantissima EO inhibited the mycelia growth of P. italicum by 98%. Overall, B. cinerea displayed the highest sensitivity to EOs than P. italicum and A. alternata. G. fragrantissima, C. sempervirens, C. nardus, P. asperum, Mentha piperita, Foeniculum vulgare, C. verrum, and S. aromaticum EOs showed the highest inhibition for these three pathogens. Minimum inhibitory concentrations were lower for C. verrum and S. aromaticum EOs, ranging between 0.31 and 0.45 mg/mL and 0.37 to 0.57 mg/mL, respectively, against the three pathogens. The tested EOs inhibited the in vitro growth of three of the main postharvest fungal pathogens. Further studies are needed to confirm these activities in vivo.

Development of a based-chitin-chitinase nanostructured biosensor for the detection of fungal complex on papaya fruit during storage

Postharvest fungi significantly reduce the storage life of papaya fruit. Among the fungal cell wall components, chitin is an important biomolecule that could serve as a biomarker. This research aimed to develop a biosensor with immobilized chitinases on zinc oxide nanoparticles (ZnO-NPs) to recognize the chitin of phytopathogenic fungi of papaya fruit. The ZnO-NPs were less than 20 nm in size, as observed by TEM, and less than 1000 nm using DLS. In addition, flower-shaped structures were visualized with the use of SEM. Fourier transform infrared spectroscopy (FTIR) confirmed the main chitin and chitinase enzyme (NH and OH) functional groups and ZnO. The portable biosensor showed differences among papaya in terms of those with evident fungal growth (478 kHz), those without evident fungal growth (462 kHz), and papaya boughtfrom asupermarket (464–481 kHz). Additionally, the presence of fungi in all treatments was confirmed, but the lowest incidence was in papaya without evident fungal growth. Thus, the biosensor could recognize fungi in papaya, an ability that could be implemented in the postharvest handling of this horticultural product in the future.

Encapsulation of thymol and limonene in metal–organic frameworks for inhibition of Colletotrichum musae growth

SummaryMonoterpenes are the most prevalent compounds found in essential oils. They exhibit inhibitory actions against phytopathogenic postharvest fungi. Direct application limits their effectiveness due to their instability, high volatility, hydrophobicity and susceptibility to degradation. Encapsulation systems using metal–organic frameworks (MOFs) have been developed to maximise their use. In this study, four protocols were shown to encapsulate thymol and limonene in porous solids, such as ZIF‐8, UiO‐66‐(COOH)2 and zeolite 13X. Vapourisation and diffusion at 60 °C for 16 h was found to be the most efficient encapsulation process. A larger amount of thymol than limonene was loaded in the porous solids. Thymol released from MOFs slowed down the growth of Colletotrichum musae by up to 6 days at 25 °C. There was a sustained release of thymol even beyond the period of maximum fungal growth. This proof‐of‐concept study revealed the potential utility of MOFs as carriers of thymol against postharvest fungi.

Iron Competition as an Important Mechanism of Pulcherrimin-Producing Metschnikowia sp. Strains for Controlling Postharvest Fungal Decays on Citrus Fruit.

This study identified and tested fruit-isolated Metschnikowia yeasts against three major postharvest citrus pathogens, namely, Penicillium digitatum, Penicillium italicum, and Geotrichum citri-aurantii, and further evaluated the impact of FeCl3 on the biocontrol efficiency of pulcherrimin-producing M. pulcherrima strains. Based on the characterization of the pigmented halo surrounding the colonies and the analysis of the D1/D2 domain of 26S rDNA, a total of 46 Metschnikowia sp. were screened and identified. All 46 Metschnikowia strains significantly inhibited the hyphal growth of Penicillium digitatum, Penicillium italicum, and Geotrichum citri-aurantii, and effectively controlled the development of green mold, blue mold and sour rot of citrus fruit. The introduction of exogenous FeCl3 at certain concentrations did not significantly impact the pulcherriminic acid (PA) production of pigmented M. pulcherrima strains, but notably diminished the size of pigmented zones and the biocontrol efficacy against the three pathogens. Iron deficiency sensitivity experiments revealed that P. digitatum and P. italicum exhibited higher sensitivity compared to G. citri-aurantii, indicating that iron dependence varied among the three pathogens. These results suggested that M. pulcherrima strains, capable of producing high yields of PA, possessed great potential for use as biocontrol agents against postharvest citrus diseases. The biocontrol efficacy of these yeasts is mainly attributed to their ability to competitively deplete iron ions in a shared environment, with the magnitude of their pigmented halo directly correlating to their antagonistic capability. It is worth noting that the level of sensitivity of pathogens to iron deficiency might also affect the biocontrol effect of pulcherrimin-producing M. pulcherrima.

In Vitro Antioxidant and Antifungal Activities of Four Essential Oils and Their Major Compounds against Post-Harvest Fungi Associated with Chickpea in Storage.

The antifungal and antioxidant properties of essential oils (EOs) derived from four plants were assessed in vitro: Rosmarinus officinalis, Myrtus communis, Origanum compactum, and Eugenia aromatica. These plants are renowned for their diverse biological activities. Antioxidant activities were evaluated using DPPH, ABTS, and TAC tests. Antifungal activity was tested against four postharvest pathogens associated with chickpea in storage: Fusarium culmorum, Rhizopus oryzae, Penicillium italicum, and Aspergillus niger, using the broth microdilution technique. Additionally, the efficacy of several major compounds against fungi found in the EOs 1,8-cineole, carvacrol, and eugenol was evaluated. Furthermore, this study explored the potential synergy of combining eugenol and carvacrol in various ratios. Based on the results, E. aromatica EO exhibited the highest antioxidant activity, as evidenced by its lowest IC50 values for a DPPH of 0.006 mg/mL. This EO also demonstrated the best antifungal activity, with MIC values ranging from 0.098 to 0.13 μL/mL. The high concentration of eugenol in this oil was identified as a contributing factor to its potent antifungal effects. The individual application of eugenol displayed significant antifungal efficacy, which was further enhanced by incorporating carvacrol at a 1:3 ratio. This synergistic combination presents promising potential for the development of specific formulations aimed at optimizing grain protection during storage.

Meyerozyma strains as biocontrol agents against postharvest phytopathogens of jackfruit (Artocarpus heterophyllus Lam.)

Jackfruit is a tropical fruit highly perishable due to phytopathogenic diseases, with up to 35% postharvest losses. Currently, the control of these diseases is sought through the use of natural alternatives such as biocontrol agents. Therefore, this work aimed to identify the phytopathogens affecting jackfruit in postharvest and to study the antagonism of Meyerozyma guilliermondii and Meyerozyma caribbica for disease control. Eight postharvest fungi were identified using morphological and molecular techniques; those with high pathogenicity were Lasiodiplodia theobromae, Rhizopus sp., and Neofusicoccum batangarum. Meyerozyma guilliermondii gave the highest mycelial inhibitions, 100, 96, and 90% against Rhizopus sp., L. theobromae, and N. batangarum, respectively. The lowest incidences of Rhizopus sp. decay were 22 and 32%, with M. guilliermondii and M. caribbica, respectively. Neofusicoccum batangarum was identified for the first time in Nayarit as a postharvest pathogen for jackfruit. Yeasts showed antagonistic effects against these phytopathogens with inhibitions higher than 68%.

ArfA and SarA small GTPases involved in growth, patulin biosynthesis and virulence of Penicillium expansum

Although the Sar/Arf GTPase belonging to a small family of GTPases contributes to growth of fungi, its function in postharvest fungi has not been characterized. Here, ArfA and SarA gene deletion mutants were generated in Penicillium expansum. We found that ΔArfA and ΔSarA exhibited attenuated colony growth and rough colony morphology, as well as insufficient spore development. ΔArfA also increased hyphal branches. Stress experiments showed that knocking out the ArfA or SarA genes affected cell wall integrity of the P. expansum strain. In addition, ΔArfA and ΔSarA significantly downregulated the expression of genes controlling spore development (wetA, abaA and brlA) and MAPK pathway regulators (Fus3, Kss1, Hog1 and Mpk1). Absence of ArfA and SarA reduced patulin production, and the related gene expression was significantly limited. ΔArfA showed attenuated virulence in infected fruit and downregulated PG and PL gene expression. However, ΔSarA had no significant effect on fungal virulence. Taken together, both ArfA and SarA contribute to the growth, development and patulin biosynthesis in P. expansum. ArfA is also involved in the virulence of P. expansum in fruit.

Subcellular damages of pathogenic fungi combined with gene expression analysis reveals mechanisms that cold plasma controlling apricot disease

Dielectric barrier discharge (DBD) plasma technology has proven effective in controlling postharvest fungus in fruits and vegetables. However, its mechanism of action is rarely reported. In this study, DBD technology was investigated to inhibit apricot diseases under the conditions of shelf simulation, and its mechanism was analysed. Apricot fruits and pathogenic fungal spores were treated with DBD of different voltage intensities（fruits: 80 kV, 90 kV, 100 kV; spores: 80 kV, 100 kV, 120 kV). Experimental data showed that DBD plasma treatment significantly reduced the microbial biomass on the surface of apricot fruit and inhibit Rhizopus oryzae and Alternaria tenuissima. Rhizopus oryzae and Alternaria tenuissima's spore germination decreased by 74.7% and 82.0%, respectively, after 40 s of processing with 100 kV DBD treatment. To investigate DBD plasma's antibacterial mechanism, deoxyribonucleic acid damage and the morphological characteristics of fungal spores were determined; this indicated that DBD plasma treatment resulted in nuclear degradation and cell deformation. In addition, DBD treatment enhanced apricots' expression of phenylalanine ammonia-lyase 1 (PAL1), aldehyde dehydrogenase 2B7 (ALDH2B7) and GDP-L-galactose phosphorylase (VTC2), delayed disease and improved quality under shelf storage conditions. The results demonstrated that DBD plasma treatment could control the primary diseases of apricot fruit and enhance the quality by destroying microbial spores and activating the disease-resistant genes of the fruit.

Plant Extracts Control In Vitro Growth of Disease-Causing Fungi in Chayote.

The use of agrochemicals has caused environmental problems and toxicity to humans, so natural alternatives for disease control during harvest and postharvest have been evaluated. The aim of this study was to evaluate cinnamon essential oil, neem oil, and black sapote fruit extract for in vitro inhibition of fungi isolated from chayote fruit. The extracts were applied at 300, 350, and 400 ppm in Petri dishes and the mycelial growth of Fusarium oxysporum, Fusarium solani, Goetrichum sp., and Phytophthora capsici was evaluated for 7 days, and the percentage of mycelial growth inhibition per day was calculated. Cinnamon oil showed a fungicidal effect at all concentrations. Neem oil at 400 ppm showed a 42.3% reduction in the growth of F. solani and 27.8% reduction in the growth of F. oxysporum, while at 350 ppm it inhibited the mycelial growth of Phytophthora capsici by 53.3% and of Goetrichum sp. by 20.9%; finally, the black sapote extract at 400 ppm inhibited 21.9-28.6% of the growth of all fungi. The growth of postharvest fungi on chayote fruit could be prevented or reduced by applying the plant extracts evaluated at adequate concentrations.

Post-Harvest Fungi of Vitellaria paradoxa and Parkia biglosa in Chad Republic and Bioactivity of Natural Products against Some Pathogenic Fungi

In Chad Republic, kernels/grains of Vitellaria paradoxa and Parkia biglobosa are two Edible Non-Timber Forest Products (ENTFP) with high economic value. These products are colonized by un-identified post-harvest fungi that are responsible for high post-harvest losses. The objective of the study was to contribute to the management of the post-harvest diseases of kernels of V. paradoxa and P. Biglosa through natural products. To achieve this, post-harvest fungi were isolated from infected kernels and their pathogenicity tested. Then, antifungal activity of Essential Oil (EO) of Thymus algeriensis and crude extract of African panaxia was carry out by the dispersion method on the agar medium on four pathogenic fungi isolated from the two infected ENTFP. Results showed that V. paradoxa kernels were highly infected (77-95%) compared to P. biglobosa (0.6-2.6%). Fungal species frequently associated with V. paradoxa and P. Biglobosa kernels were: Aspergillus niger (46%), Rhizopus nigricans (17%), Oidium sp (22%) and Cercospora sp (8%); and Oidium sp (55%), A. niger (18%), A. flavus (18%) and Cercospora sp (6%) in V. paradoxa and P. biglobosa respectively. Pathogenicity test was positive with all the species belonging to the genus Aspergillus and with Oidium sp. Essential oil of T. vulgaris at 1.5 �l/ml and the crude extract of African panaxia at 120 �g/ml totally inhibited the growth of the four potential mycotoxigenic fungi tested; their efficacy were significantly comparable (p<0.05) to the reference fungicide (Terazeb). In vivo control of post-harvest diseases with these two natural products is being carry out.

Isolation of Aspergillus flavus strains from Bambara groundnut (Vigna subterranea (L.) Verdcourt) seeds and screening for the production of aflatoxin B1 and B2

In Burkina Faso, Bambara groundnut is the second most important food legume after cowpea, especially in rural areas. However, this crop, due to certain conditions of production, storage or preservation is susceptible to be contaminated by potential mycotoxin producing fungi. The aim of this study was to evaluate the aflatoxinogenic capacity of Aspergillus flavus isolates isolated from Bambara groundnut seeds produced in Burkina Faso. Thus, 198 isolates of fungi belonging to section Flavi were isolated from 99 samples of Bambara groundnut seeds collected in the three agro-ecological zones of Burkina Faso. From the 198 isolates, 28 were identified as Aspergillus flavus. Then, we investigated their potential for aflatoxin B1 (AFB1) and B2 (AFB2) production by growing them on rice at 25°C for 7 days. AFB1 and AFB2 were extracted and quantified by liquid chromatography–mass spectrometry (LC-MS/MS). All of the strains (28) produced AFB1 at concentrations ranging from 46.987 μg kg–1 to 1080.320 μg kg–1. However, AFB2 was produced by 26 strains with concentrations ranging from 47.200 μg kg–1 to 1760.240 μg kg–1. Globally, most of the tested strains produced higher levels of AFB1 than AFB2. The results obtained point out the risk associated with post-harvest fungi and the need for the development of storage technics to control them, for food security.

Grapefruit peel essential oil nanoemulsions: preparation, characterisation, stability and antifungal potential against Penicillium digitatum of Kinnow

SummaryHydrophobicity of essential oils poses a big hindrance for harnessing their diverse antimicrobial portfolio. The study was therefore planned to develop and explore grapefruit peel essential oil nanoemulsions (GPEO‐NEs) as an eco‐friendly hydrophilic alternate against Penicillium digitatum, a prominent postharvest fungus of kinnow. GPEO‐NEs were prepared by mixing GPEO and surfactant (Tween 80) in different ratios (v/v) viz 1:0.5–1:3 by bath and probe sonication. The 1:1 OSR GPEO‐NE (20 min) by probe sonication exhibited consistent droplet diameter (96.6 nm) and PDI (0.247). All GPEO‐NEs were evaluated for antifungal potential against P. digitatum using poisoned food technique. The GPEO‐NEs (1:1 OSR; 20 min) revealed the best efficacy (88.6%) as compared to pure GPEO (76.6%). Optical microscopy further revealed stronger suppressive activity of GPEO‐NEs for spore germination and hyphal distortion of P. digitatum than pure oil. The GPEO‐NEs can thus serve as a green alternative to synthetic fungicides for managing postharvest losses in kinnow by using these as coatings.