Inhibition of Fusarium culmorum, Penicillium chrysogenum and Rhizoctonia solani by n-hexane extracts of three plant species as a wood-treated oil fungicide

Characterization and control of Rhizoctonia solani affecting lucky bamboo (Dracaena sanderiana hort. ex. Mast.) using some bioagents

In a survey conducted during the period of March-May 2019 in nurseries, warehouses, and shops at three governorates (Alexandria, El-Behera, and Giza governorates, Egypt), symptoms of root rot, basal stem rot, and wilt disease complex were observed in the lucky bamboo (Dracaena sanderiana hort. ex. Mast.). The highest disease infection percentage was found in lucky bamboo collected from Alexandria City (47.67%), while the highest disease severity was in lucky bamboo collected from El-Behera Governorate (35.19%). Rhizoctonia solani, Fusarium oxysporum, F. solani, Aspergillus niger, and Alternaria alternate were isolated and identified in the infected lucky bamboo samples. R. solani isolates were the most dominant among the recovered fungal species with a percentage of 80.89% of the total isolates (246). Pathogenicity tests showed that R. solani was the most pathogen with 100% disease infection and 76.67% disease severity. Molecular identification characterized R. solani isolate as R. solani AUMC 15120, MZ723906. Meanwhile, four biological control agents (bioagents) were isolated from the healthy lucky bamboo samples and identified based on cultural, morphological, microscopic characteristics, and the molecular phylogenetic analysis as Clonostachys rosea AUMC 15121, OL461708; Bacillus circulans TAG1, MW441316; B. siamensis TAP1, MW441318 and Ochrobactrum anthropi TAM1, MW441317. The four bioagents showed potential inhibition of R. solani in vitro as well as in vivo on lucky bamboo plants in vase treatments compared to the untreated inoculated control as well as certain fungicides and biocides used (Moncut, Rizolex-T, Topsin-M, Bio-Zeid, and Bio-Arc). The bioagent O. anthropi showed the highest inhibition growth (85.11%) of the in vitro R. solani colony, which was not significantly different from the biocide Bio-Arc (83.78%). However, C. rosea, B. siamensis and B. circulans showed inhibition values of 65.33, 64.44, and 60.44%, respectively. On the other hand, the biocide Bio-Zeid showed less inhibitory effect (43.11%), while the lowest growth inhibition was recorded by Rizolex-T (34.22%) and Topsin-M (28.67%). Furthermore, the in vivo experiment supported the in vitro results for the most effective treatments, where all the treatments significantly decreased the percentage of infection and disease severity compared to the inoculated untreated control. Additionally, the bioagent O. anthropi showed the highest effect, i.e., the lowest disease incidence and disease severity being 13.33% and 10%, compared to 100% and 75%, respectively, in the untreated inoculated control. This was not significantly different from the fungicide Moncut (13.33% and 21%) and from the bioagent C. rosea (20% and 15%) treatments for both parameters, respectively. In conclusion, the bioagents O. anthropi MW441317 at 1 × 10⁸ CFU/ml as well as C. rosea AUMC15121 at 1 × 10⁷/ml proved to be efficient to control R. solani causing root rot, and basal stem rot on lucky bamboo, compared to fungicide Moncut and can be used for disease management without the negative impact of the chemical control. Furthermore, this is the first report of the isolation and identification of Rhizoctonia solani, a pathogenic fungus, and four biocontrol agents (Bacillus circulans, B. siamensis, Ochrobactrum anthropi and Clonostachys rosea) associated with the healthy lucky bamboo plants.

Antifungal Agents in Wood Protection—A Review

The biodegradation of wood and wood products caused by fungi is recognized as one of the most significant problems worldwide. To extend the service life of wood products, wood is treated with preservatives, often with inorganic compounds or synthetic pesticides that have a negative impact on the environment. Therefore, the development of new, environmentally friendly wood preservatives is being carried out in research centers around the world. The search for natural, plant, or animal derivatives as well as obtaining synthetic compounds that will be safe for humans and do not pollute the environment, while at the same time present biological activity is crucial in terms of environmental protection. The review paper presents information in the literature on the substances and chemical compounds of natural origin (plant and animal derivatives) and synthetic compounds with a low environmental impact, showing antifungal properties, used in research on the ecological protection of wood. The review includes literature reports on the potential application of various antifungal agents including plant extracts, alkaloids, essential oils and their components, propolis extract, chitosan, ionic liquids, silicon compounds, and nanoparticles as well as their combinations.

Plantago lagopus extract as a green fungicide induces systemic resistance against Rhizoctonia root rot disease in tomato plants

Extensive use of chemical control agents and fungicides typically leads to numerous risks to human health and the environment. Using plant extracts as natural substances represents a dual key for the environment and sustainable food production, as it reduces the input of synthetic pesticides into the environment and/or controls plant pathogens. For the first time, a Plantago lagopus ethanolic extract has been characterized and evaluated for its protective and curative effects against Rhizoctonia solani in tomato plants. The results showed that P. lagopus extract (10 μg/ml) completely inhibited R. solani mycelial growth in vitro. At 20 days of post fungal inoculation, the results demonstrated that using P. lagopus extract (100 μg/ml) in vivo enhanced tomato plant growth by significantly increasing shoot and root parameters in protective and curative treatments. Furthermore, the protective and curative treatments significantly reduced the disease index by 18.66 and 38.66%, respectively. Induction of systemic resistance with upregulation of PR-1 and PR-2 and a significant increase in the transcriptional levels of PR-3 and CHS in all P. lagopus extract-treated tomato plants were reported compared to untreated plants. HPLC analysis showed that the most common polyphenolic components detected in P. lagopus extract were rutin (74206.3 mg/kg), naringenin (2388.74 mg/kg), quercetin (1249.13 mg/kg), and p-hydroxybenzoic acid (1035.87 mg/kg). In addition, the ellagic acid (798.47 mg/kg), vanillic acid (752.55 mg/kg), catechol (648.89 mg/kg), cinnamic acid (332.51 mg/kg), ferulic acid (296.32 mg/kg), benzoic acid (295.95 mg/kg), and chlorogenic acid (116.63 mg/kg) were also reported. Our study is the first to show that P. lagopus extract can help plants fight off R. solani fungal infection. Furthermore, the findings imply that using the P. lagopus extract as a natural biocontrol agent could be a sustainable strategy to manage plant fungal diseases.

Impact of Silver Nanoparticles on Lemon Growth Performance: Insecticidal and Antifungal Activities of Essential Oils From Peels and Leaves

Ten-year-old lemon (Citrus limon L. cv. Eureka) was used during the 2019 and 2020 seasons to investigate the effect of AgNPs at control, 5, 7.5, and 10 mg/L as a foliar application on vegetative growth, yield, and fruit quality. The selected trees were subjected to agricultural practices applied in the field during the study. The results indicated that the foliar application of AgNPs positively improved the shoot length, total chlorophyll, flower, and fruit set percentage, fruit yield, physical and chemical characteristics of fruits, and leaf mineral composition from macro and micronutrients compared to control in both seasons. The foliar application of AgNPs at 10 mg/L showed the highest mean values followed by 7.5 and 5 mg/L, respectively, for the previous characteristics. The treated leaves and fruit peels were hydrodistillated to extract the essential oils (EOs), and GC-MS analysis of leaf EOs. The analysis of leaves EOs showed the presence of neral, geranial, neryl acetate, and limonene as the main abundant bioactive compounds. While in peel the main compounds were neral, geranial, neryl acetate, D-limonene, geraniol acetate, linalool, and citronellal. Toxin effect of both EOs from leaves and peels were evaluated on the rice weevils (Sitophilus oryzae) and the results indicated a higher effect of lemon peel EOs than leaves based on mortality percentage and the values of LC50 and LC95 mg/L. Melia azedarach wood samples loaded with the produced lemon EOs were evaluated for their antifungal activity against the molecularly identified fungus, Fusarium solani (acc # OL410542). The reduction in mycelial growth was increased gradually with the applied treatments. The most potent activity was found in lemon leaf EOs, while peel EOs showed the lowest reduction values. The mycelial growth reduction percentages reached 72.96 and 52.59%, by 0.1% leaf and peel EOs, respectively, compared with control.

Pomegranate trees quality under drought conditions using potassium silicate, nanosilver, and selenium spray with valorization of peels as fungicide extracts

The current study was performed on 8 years old "Succary" pomegranate cultivar (Punica granatum L.) during the 2019 and 2020 seasons. One hundred pomegranate trees were chosen and sprayed three times at the beginning of flowering, full bloom, and 1 month later with the following treatments: water as control, 0.025, 0.05 and 0.1 mg/L Se; 5 mL/L, 7.5 and 10 mL/L Ag NPs, and 0.5, 1 and 2 mg/L K₂Si₂O₅. The results showed that spraying of SE, Ag NPs, and K₂Si₂O₅ ameliorated the shoot length, diameter, leaf chlorophyll content, set of fruiting percentage, and fruit yield per tree and hectare compared to control through studying seasons. Moreover, they improved the fruit weight, length, and diameter, as well as total soluble solids, total, reduced, and non-reduced sugars percent, while they lessened the juice acidity percentage compared to control. The most obvious results were noticed with Se at 0.1 mg/L, Ag NPs at 10 mL/L, and K₂Si₂O₅ at 2 mg/L in both experimental seasons over the other applied treatments. By HPLC analysis, peel extracts showed the presence of several bioactive compounds of catechol, syringic acid, p-coumaric acid, benzoic acid, caffeic acid, pyrogallol, gallic acid, ferulic acid, salicylic acid, cinnamic acid, and ellagic acid. The extracts applied to Melia azedarach wood showed promising antifungal activity against Rhizoctonia solani and were considered wood-biofingicides.

Photosynthetic Pigments and Biochemical Response of Zucchini (Cucurbita pepo L.) to Plant-Derived Extracts, Microbial, and Potassium Silicate as Biostimulants Under Greenhouse Conditions

There are many technological innovations in the field of agriculture to improve the sustainability of farmed products by reducing the chemicals used. Uses of biostimulants such as plant extracts or microorganisms are a promising process that increases plant growth and the efficient use of available soil resources. To determine the effects of some biostimulants' treatments on the photosynthetic pigments and biochemicals composition of zucchini plants, two experiments were conducted in 2019 and 2020 under greenhouse conditions. In this work, the effects of beneficial microbes (Trichoderma viride and Pseudomonas fluorescens), as well as three extracts from Eucalyptus camaldulensis leaf extract (LE), Citrus sinensis LE, and Ficus benghalensis fruit extract (FE) with potassium silicate (K₂SiO₃) on productivity and biochemical composition of zucchini fruits, were assessed as biostimulants. The results showed that E. camaldulensis LE (4,000 mg/L) + K₂SiO₃ (500 mg/L) and T. viride (10⁶ spore/ml) + K₂SiO₃ (500 mg/L) gave the highest significance yield of zucchini fruits. Furthermore, the total reading response of chlorophylls and carotenoids was significantly affected by biostimulants' treatments. The combination of K₂SiO₃ with E. camaldulensis LE increased the DPPH scavenging activity and the total phenolic content of zucchini fruits, in both experiments. However, the spraying with K₂SiO₃ did not observe any effects on the total flavonoid content of zucchini fruits. Several phenolic compounds were identified via high-performance liquid chromatography (HPLC) from the methanol extracts of zucchini fruits such as syringic acid, eugenol, caffeic acid, pyrogallol, gallic acid, ascorbic acid, ferulic acid, α-tocopherol, and ellagic acid. The main elemental content (C and O) analyzed via energy-dispersive X-ray spectroscopy (EDX) of leaves was affected by the application of biostimulants. The success of this work could lead to the development of cheap and easily available safe biostimulants for enhancing the productivity and biochemical of zucchini plants.

Natural Plant Extracts and Microbial Antagonists to Control Fungal Pathogens and Improve the Productivity of Zucchini (Cucurbita pepo L.) In Vitro and in Greenhouse

Background: Natural plant extracts and microbial antagonists have the potential for use in increasing the fungal resistance and productivity of horticulture plants. Methods: The purpose of this study was to evaluate the ability of both natural plant extracts and microbial antagonists as a biotical control of some fungal pathogens, i.e., Fusarium ssp., Exserohilum ssp. and Nigrospora ssp., along with improving the growth and productivity performance of zucchini under greenhouse conditions. Eucalyptus camaldulensis leaf extract (LE), Citrus sinensis LE, Ficus benghalensis fruit extract (FE), and two microbial antagonists Pseudomonas fluorescens (accession no. MW647093) and Trichoderma viride (accession no. MW647090) were tested under in vitro and in vivo conditions. Through morphological characteristics and the internal transcribed spacer (ITS) region, Fusarium solani (accession no. MW947256), F. oxysporum (accession no. MW947254), Exserohilum rostratum (accession no. MW947255), and Nigrospora lacticolonia (accession no. MW947253) were identified. HPLC analysis was used for the identification of phenolic compounds (PCs) and flavonoid compounds (FCs) in the extracts. Results: The highest inhibition percentage of fungal growth (IPFG) against F. oxysporum was obtained with P. fluorescens, T. viride, and E. camaldulensis LE (4000 mg/L); F. solani with P. fluorescens, T. viride, and C. sinensis LE (4000 mg/L); Exserohilum rostratum with P. fluorescens, Ficus benghalensis FE (4000 mg/L) and E. camaldulensis LE (4000 mg/L), and N. lacticolonia with P. fluorescens. Using HPLC analysis, the abundant PCs in E. camaldulensis LE were pyrogallol, and caffeic acid, those in C. sinensis LE were syringic acid and ferulic acid, and those in F. benghalensis FE were gallic acid and syringic acid. In addition, the abundant FCs in E. camaldulensis LE were kaempferol, and naringin, those in C. sinensis LE were hesperidin and quercetin, and those in F. benghalensis FE were kaempferol and quercetin. Under greenhouse experiments, T. viride and E. camaldulensis LE (4000 mg/L) followed by P. fluorescens + T. viride treatments gave the best results of zucchini plants in terms of leaf area, fruits number per plant, yield per plant, and total yield (marketable and non-marketable). Conclusions: Plant extracts and bioagents can be used to control some zucchini fungal pathogens and increase the productivity performance of zucchini plants.

Moringa oleifera seeds-removed ripened pods as alternative for papersheet production: antimicrobial activity and their phytoconstituents profile using HPLC

In the present study, and for the waste valorization, Moringa oleifera seeds-removed ripened pods (SRRP) were used for papersheet production and for the extraction of bioactive compounds. Fibers were characterized by SEM–EDX patterns, while the phytoconstituents in ethanol extract was analyzed by HPLC. The inhibition percentage of fungal mycelial growth (IFMG) of the treated Melia azedarach wood with M. oleifera SRRP extract at the concentrations of 10,000, 20,000, and 30,000 µg/mL against the growth of Rhizoctonia solani and Fusarium culmorum was calculated and compared with fluconazole (25 µg). The produced papersheet was treated with the ethanol extract (4000, 2000, and 1000 µg/mL) and assayed for its antibacterial activity against Agrobacterium tumefaciens, Erwinia amylovora, and Pectobacterium atrosepticum by measuring the inhibition zones and minimum inhibitory concentrations (MICs). According to chemical analysis of M. oleifera SRRP, benzene:alcohol extractives, holocellulose, lignin, and ash contents were 7.56, 64.94, 25.66 and 1.53%, respectively, while for the produced unbleached pulp, the screen pulp yield and the Kappa number were 39% and 25, respectively. The produced papersheet showed tensile index, tear index, burst index, and double fold number values of 58.8 N m/g, 3.38 mN m²/g, 3.86 kPa m²/g, and 10.66, respectively. SEM examination showed that the average fiber diameter was 16.39 µm, and the mass average of for elemental composition of C and O by EDX were, 44.21%, and 55.79%, respectively. The main phytoconstituents in the extract (mg/100 g extract) by HPLC were vanillic acid (5053.49), benzoic acid (262.98), naringenin (133.02), chlorogenic acid (66.16), and myricetin (56.27). After 14 days of incubation, M. oleifera SRRP extract-wood treated showed good IFMG against R. solani (36.88%) and F. culmorum (51.66%) compared to fluconazole, where it observed 42.96% and 53.70%, respectively. Moderate to significant antibacterial activity was found, where the minimum inhibitory concentration (MIC) values were 500, 650, and 250 µg/mL against the growth of A. tumefaciens, E. amylovora, and P. atrosepticum respectively, which were lower than the positive control used (Tobramycin 10 µg/disc). In conclusion, M. oleifera SRRP showed promising properties as a raw material for pulp and paper production as well as for the extraction of bioactive compounds.

Plants-derived bioactives: Novel utilization as antimicrobial, antioxidant and phytoreducing agents for the biosynthesis of metallic nanoparticles

Medicinal and aromatic higher plants are sustainable resources for natural product compounds, including essential oils, phenolics, flavonoids, alkaloids, glycosides, and saponins. Extractives and essential oils as well as their bioactive compounds have many uses due to their antimicrobial, anticancer, and antioxidant properties as well as application in food preservation. These natural compounds have been reported in many works, for instance biofungicide with phenolic and flavonoid compounds being effective against mold that causes discoloration of wood. Additionally, the natural extracts from higher plants can be used to mediate the synthesis of nanoparticle materials. Therefore, in this review, we aim to promote and declare the use of natural products as environmentally eco-friendly bio-agents against certain pathogenic microbes and make recommendations to overcome the extensive uses of conventional pesticides and other preservatives.

Morphological and molecular identification of Cladosporium sphaerospermum isolates collected from tomato plant residues

This study was conducted at the Agriculture College University of Karbala, Iraq to isolate and morphologically and molecularly diagnose thirteen Cladosporium isolates collected from tomato plant residues present in desert regions of Najaf and Karbala provinces, Iraq. We diagnosed the obtained isolates by PCR amplification using the ITS1 and ITS4 universal primer pair followed by sequencing. PCR amplification and analysis of nucleotide sequences using the BLAST program showed that all isolated fungi belong to Cladosporium sphaerospermum. Analysis of the nucleotide sequences of the identified C. sphaerospermum isolates 2, 6, 9, and 10 showed a genetic similarity reached 99%, 98%, 99%, and 99%, respectively, with those previously registered at the National Center for Biotechnology Information (NCBl). By comparing the nucleotide sequences of the identified C. sphaerospermum isolates with the sequences belong to the same fungi and available at NCBI, it was revealed that the identified C. sphaerospermum isolates 2, 6, 9, and 10 have a genetic variation with those previously recorded at the National Center for Biotechnology Information (NCBl); therefore, the identified sequences of C. sphaerospermum isolates have been registered in GenBank database (NCBI) under the accession numbers MN896004, MN896107, MN896963, and MN896971, respectively.

Post-Harvest Enhancing and Botrytis cinerea Control of Strawberry Fruits Using Low Cost and Eco-Friendly Natural Oils

This work investigates an experimental study for using low-cost and eco-friendly oils to increase the shelf life of strawberry fruit. Three natural oils were used: (i) Eucalyptus camaldulensis var obtuse, (ii) Mentha piperita green aerial parts essential oils (EOs), and (iii) Moringa oleifera seeds n-hexane fixed oil (FO). Furthermore, a mixture of EOs from E. camaldulensis var obtusa and M. piperita (1/1 v/v) was used. The treated fruits were stored at 5 °C and 90% relative humidity (RH) for 18 days. HPLC was used to analyse the changes in phenolic compounds during the storage periods. The effects of biofumigation through a slow-release diffuser of EOs (E. camaldulensis var obtusa and M. piperita), or by coating with M. oleifera FO, were evaluated in terms of control of post-harvest visual and chemical quality of strawberry fruits. The post-harvest resistance of strawberry fruits to Botrytis cinerea fungal infection was also evaluated. As a result, the EO treatments significantly reduced the change in visual and chemical quality of strawberry fruit. Additionally, changes in the titratable acidity of moringa FO-coated strawberry fruits were delayed. EO treatments improved total soluble solids, total phenols, ascorbic acid, antioxidants and peroxidase. E. camaldulensis var obtusa and M. piperita (1/1 v/v) EO-vapour fruit exhibited a slower rate of deterioration, compared to other treatments in all tested, in two experiments. The lowest colour change (ΔE) was observed inthe fruit treated with E. camaldulensis var obtusa EO and M. oleifera FO. HPLC showed changes in phenolic compounds’ concentration, where p-coumaric acid, caffeic acid, gallic acid, ferulic acid and ellagic acid were mostly identified in the fruits treated with the oils. SEM examination confirmed the potential decrease in fungal growth as the fruits were treated with EOs. In conclusion, the treatment of EOs during different storage periods showed promising characterisations for strawberry fruit quality.

Antimycotoxigenic Activity of Beetroot Extracts against Alternaria alternata Mycotoxins on Potato Crop

Alternaria species, mainly air-borne fungi, affect potato plants, causing black spots symptoms. Morphological identification, pathogenicity assessment, and internal transcribed spacer (ITS) molecular identification confirmed that all isolates were Alternaria alternata. The annotated sequences were deposited in GenBank under accession numbers MN592771–MN592777. HPLC analysis revealed that the fungal isolates KH3 (133,200 ng/g) and NO3 (212,000 ng/g) produced higher levels of tenuazonic acid (TeA) and alternariol monomethyl ether (AME), respectively. Beet ethanol extract (BEE) and beet methanol extract (BME) at different concentrations were used as antimycotoxins. BME decreased the production of mycotoxins by 66.99–99.79%. The highest TeA reduction rate (99.39%) was reported in the KH3 isolate with 150 µg/mL BME treatment. In comparison, the most effective AME reduction rate (99.79%) was shown in the NO3 isolate with 150 µg/mL BME treatment. In the same way, BEE application resulted in 95.60–99.91% mycotoxin reduction. The highest TeA reduction rate (99.91%) was reported in the KH3 isolate with 150 µg/mL BEE treatment, while the greatest AME reduction rate (99.68%) was shown in the Alam1 isolate with 75 µg/mL BEE treatment. GC-MS analysis showed that the main constituent in BME was the antioxidant compound 1-dodecanamine, n,n-dimethyl with a peak area of 43.75%. In contrast, oxirane, methyl- (23.22%); hexadecanoic acid, methyl ester (10.72%); and n-hexadecanoic acid (7.32%) were the main components in BEE found by GC-MS. They are probably antimicrobial molecules and have an effect on the mycotoxin in general. To our knowledge, this is the first study describing the antimycotoxigenic activity of beet extracts against A. alternata mycotoxins-contaminated potato crops in Egypt, aimed to manage and save the environment.

New Approach for Using of Mentha longifolia L. and Citrus reticulata L. Essential Oils as Wood-Biofungicides: GC-MS, SEM, and MNDO Quantum Chemical Studies

BACKGROUND

Fungi growing on wood cause deterioration of stored food materials or discoloration of the wood itself, and the search for new and safe bioagents is recently needed.

METHODS

Essential oils (EOs) from aerial parts from Mentha longifolia L. and Citrus reticulata L., analyzed by gas chromatography-mass spectrometry (GC-MS), were tested for their antifungal activity by the vapor method against four common fungi, Aspergillus flavus, A. niger, A. fumigatus, and Fusarium culmorum, and confirmed by SEM examination as the oils applied on wood samples.

RESULTS

The most abundant compounds identified in the EO from M. longifolia were menthone and eucalyptol; in C. reticulata EO, they were β-caryophyllene, β-caryophyllene oxide, and β-elemene. EOs from M. longifolia and C. reticulata, at 500 and 250 µL/mL, showed potent antifungal activity against A. flavus and A. fumigatus, with 100% fungal mycelial inhibition growth (FMIG). C. reticulata and M. longifolia EOs, at 125 µL/mL, observed FMIG values of 98% and 95%, respectively, against A. fumigatus. M. longifolia EO, at 500 and 250 µL/mL, showed potent activity against A. niger, with 100% FMIG. F. culmorum completely inhibited (100% FMIG) EOs from M. longifolia and C. reticulata applied at 500 µL/mL. Pinus roxburghii Sarg. Wood, treated with M. longifolia at 125 µL/mL, showed inhibition zone values of 7.33 and 21.33 mm against A. flavus and A. niger, respectively.

CONCLUSIONS

Both oils possessed good wood-biofungicide activity with the vapor method, as clearly shown by the SEM examination. These activities suggest their possible use as natural wood preservatives.

Anti-Termitic Activity of Three Plant Extracts, Chlorpyrifos, and a Bioagent Compound (Protecto) against Termite Microcerotermes eugnathus Silvestri (Blattodea: Termitidae) in Egypt

A trend towards environmentally friendly chemicals for use in termite management has been occurring globally. This study examined three naturally occurring plant extracts from Lavandula latifolia (Spike lavender), Origanum vulgare (Marjorum), and Syzygium aromaticum (Clove) against the termite Microcerotermes eugnathus. Plant extract results were compared to two commercially used termite pesticides, the bio-insecticide, Bacillus thuringiensis var. kurstaki (Protecto 9.4% WP) and Dursban (Chlorpyrifos 48%). Gas chromatography-mass spectrometry (GC-MS) analysis was used to identify the main compounds in the three plant extracts. The main compounds in Lavandula Latifolia were linalool (21.49%), lavandulol (12.77%), β-terpinyl acetate (10.49%), and camphor (9.30%). Origanum vulgare extract contained thymol (14.64%), m-cymene (10.63%), linalool (6.75%), and terpinen-4-ol (6.92%) as main compounds. Syzygium aromaticum contained eugenol (99.16%) as the most abundant identified compound. The extract of O. vulgare caused the highest termite death rate, with an LC50 of 770.67 mg/L. Exposure to lavender extract showed a high death rate with an LC50 of 1086.39 mg/L. Clove extract did not show significant insecticidal activity with an LC50 > 2000 mg/L. Significant termiticide effects were found, with LC50 values of 84.09 and 269.98 mg/L for soldiers and workers under the application of Dursban and Protecto, respectively. The LC50 values reported for nymphs were <120, <164.5, and 627.87 mg/L after exposure to Dursban, Protecto, and O. vulgare extract, respectively. The results of the study show that some of the extracts have low toxicity compared to the bioagent and Dursban, and may show promise as natural termiticides, particularly as extracts from O. vulgare.

The Phytochemical, Antifungal, and First Report of the Antiviral Properties of Egyptian Haplophyllum tuberculatum Extract

In this study, ethanol whole plant extract (WPE) of Haplophyllum tuberculatum was characterized and tested for its antifungal and antiviral activities against Fusarium culmorum, Rhizoctonia solani and tobacco mosaic virus (TMV). High Performance Liquid Chromatography (HPLC) analysis showed that the main phytochemical constituents of H. tuberculatum WPE were resveratrol (5178.58 mg/kg), kaempferol (1735.23 mg/kg), myricetin (561.18 mg/kg), rutin (487.04 mg/kg), quercetin (401.04 mg/kg), and rosmarinic acid (387.33 mg/kg). By increasing H. tuberculatum WPE at concentrations of 1%, 2%, and 3%, all of the fungal isolates were suppressed compared to the two positive and negative controls. Under greenhouse conditions, WPE-treated Chenopodium amaranticolor plants strongly inhibited TMV infection and significantly reduced TMV accumulation levels when compared to non-treated plants. Moreover, the induction of systemic resistance with significant increases in the transcriptional levels of the pathogenesis-related protein-1 (PR-1), chalcone synthase (CHS), and hydroxycinnamoyl-CoA quinate transferase (HQT) genes for treated plants were noticed at 3 and 5 days post-inoculation (dpi) for both assays. To the best of our knowledge, this is the first reported observation of the antiviral activity of H. tuberculatum extract against plant viral infections. Finally, the results obtained suggest that H. tuberculatum WPE can be considered a promising source of both antifungal and antiviral substances for practical use and for developing plant-derived compounds for the effective management of plant diseases.

Eucalyptus camaldulensis, Citrus aurantium, and Citrus sinensis Essential Oils as Antifungal Activity against Aspergillus flavus, Aspergillus niger, Aspergillus terreus, and Fusarium culmorum

Several molds are able to colonize wood and many building products or solid wood causing losses for their valuable uses. Essential oils (EOs) from aromatic plants can be used as an ecofriendly biofungicide against the growth of several molds. EOs from Eucalyptus camaldulensis, Citrus aurantium, and C. sinensis have a broad-spectrum antimicrobial activity. EOs from of E. camaldulensis air-dried aerial parts, C. aurantium leaf and C. sinensis peel, and their combinations (1:1 v/v) were evaluated for their antifungal activity against the growth of four common mold fungi (Aspergillus flavus, A. niger, A. terreus, and Fusarium culmorum). The chemical compositions of the EOs were analyzed with GC/MS. The main compounds in EO from E. camaldulensis were spathulenol (20.84%), eucalyptol (12.01%), and sabinene (9.73%); in C. aurantium were linalyl acetate (42.29%), and linalool (29.76%); and in C. sinensis were D-limonene (73.4%) and γ-terpinene (22.6%). At 50 µL/mL, C. sinensis EO showed the highest fungal mycilial growth inhibition (FMGI) percentage (86.66%) against A. flavus. C. sinensis, E. camaldulensis, and E. camaldulensis/C. sinensis showed FMGI values of 96%, 91.66%, and 75.66% respectively, against A. niger. EOs from C. aurantium and C. sinensis showed potent activity against A. terreus (100% FMGI), while C. aurantium/E. camaldulensis and E. camaldulensis/C. sinensis showed FMGI values of 74.33% and 70.66%, respectively. Potent activity against F. culmorum with 100% was observed as the application of E. camaldulensis and C. sinensis EOs at 50 µL/mL, while E. camaldulensis/C. sinensis (50 µL/mL) showed FMGI value of 65.66%. The results suggest using the EOs and their combinations from E.camaldulensis, C. aurantium, and C. sinensis as a biofungicide against molds. The potent properties of EOs offer the possibility of using them as eco-friendly, safe, and cost-effective antimicrobials for molds that could cause discoloration of the wood packaging or food spoilage.

Antiviral, antifungal, and insecticidal activities of Eucalyptus bark extract: HPLC analysis of polyphenolic compounds

In this study, the antiviral, antifungal, and insecticidal and HPLC analysis of polyphenolic compounds of Eucaluptus camaldulensis Dehnh. bark extract (ECBE) were evaluated. Three fungi, namely Fusarium culmorum MN398395, Rhizoctonia solani MN398397, and Botrytis cinerea MN398399 were used to colonize wood blocks of chinaberry that was previously treated with different concentrations of ECBE at 1%, 2%, and 3%. Antiviral evaluations (protective, curative, and inactivating activities) of the extract at 100 μg/mL were assayed against Tobacco mosaic virus (TMV) MG264131 using the half-leaf method to determine the inhibitory percentage towards the number of local lesions. The protective treatment of Nicotiana glutinosa leaves exhibited excellent activity (72.22%) with a 91.1-fold reduction in TMV-CP accumulation in infected tissues. Furthermore, Real-time quantitative PCR revealed that the expression level of PAL and PR-1 (salicylic acid marker) genes were significantly up regulated at four days-post inoculation (dpi) for all treatments compared to untreated leaves. The insecticidal effect was screened by the contact and fumigant methods against Tribolium castaneum (Herbst) and Sitophilus oryzae L. in vitro. In contact assay, all concentrations 1, 5, 10, 20 and 30 ppm caused 100% toxicity to the two tested pests within 24 h, whereas the fumigant assay, gave the highest mortality against T. castaneum and S. oryzae by 20 ppm (61.66%) and 30 ppm (57.77%), respectively after 24 h. The HPLC analysis of ECBE revealed that benzoic acid, quinol, salicylic acid, myricetin, and rutin were the most abundant polyphenolic compounds found in the extract. In conclusion, when the extract concentration increases, the growth of fungal mycelia was decreased compared with the control, especially against F. culmorum. According to the hypotheses of the results, the ECBE recommended to prevent the wood from discoloration, fungal molds by acting as bio-preservative, also trigger the resistance of plants against viral infection and high toxicity against stored-product insects.

Bioactivity of Selected Phenolic Acids and Hexane Extracts from Bougainvilla spectabilis and Citharexylum spinosum on the Growth of Pectobacterium carotovorum and Dickeya solani Bacteria: An Opportunity to Save the Environment

Phenolic acids and natural extracts, as ecofriendly environmental agents, can be used as bio bactericides against the growth of plant pathogenic bacteria. In this study, isolation trails from infected potato tubers and stems that showed soft rot symptoms in fields revealed two soft rot bacterial isolates and were initially identified through morphological, physiological, and pathogenicity tests. The molecular characterization of these isolates via PCR, based on the 16S rRNA region, was carried out by an analysis of the DNA sequence via BLAST and Genbank, and showed that the soft rot bacterial isolates belong to Pectobacterium carotovorum subsp. carotovorum (PCC1) and Dickeya solani (Ds1). The in vitro results of the tested phenolic acids against the cultured bacterial isolates proved that concentrations of 800, 1600, and 3200 μg/mL were the most effective. Ferulic acid was the potent suppressive phenolic acid tested against the Ds1 isolate, with an inhibition zone ranging from 6.00 to 25.75 mm at different concentrations (25–3200 μg/mL), but had no effect until reaching a concentration of 100 μg/mL in the PCC1 isolate, followed by tannic acid, which ranged from 7.00 to 25.50 mm. On the other hand, tannic acid resulted in a significant decrease in the growth rate of the PCC1 isolate with a mean of 9.11 mm. Chlorogenic acid was not as effective as the rest of the phenolic acids compared with the control. The n-hexane oily extract (HeOE) from Bougainvillea spectabilis bark showed the highest activity against PCC1 and Ds1, with inhibition zone values of 12 and 12.33 mm, respectively, at a concentration of 4000 μg/mL; while the HeOE from Citharexylum spinosum wood showed less activity. In the GC/MS analysis, nonanal, an oily liquid compound, was found ata percentage of 38.28%, followed by cis-2-nonenal (9.75%), which are the main compounds in B. spectabilis bark HeOE, and 2-undecenal (22.39%), trans-2-decenal (18.74%), and oleic acid (10.85%) were found, which are the main compounds in C. spinosum wood HeOE. In conclusion, the phenolic acids and plant HeOEs seem to raise the resistance of potato plants, improving their defense mechanisms against soft rot bacterial pathogens.

Impact of Three Natural Oily Extracts as Pulp Additives on the Mechanical, Optical, and Antifungal Properties of Paper Sheets Made from Eucalyptus camaldulensis and Meryta sinclairii Wood Branches

In the pulp and paper industry, several studies have been done to improve and enhance the properties of the mechanical, optical, and antimicrobial activities of pulp produced with different additives. In the present study, pulp of wood branches (WBs) from Eucalyptus camaldulensis Dehnh. and Meryta sinclairii (Hook.f.) Seem. was treated with n-hexane oily extracts (HeOE) from Melia azedarach L. fruits, Magnolia grandiflora L. leaves, and Sinapis alba L. seeds as additives at concentrations of 1%, 3%, and 5% based on oven-dry pulp weight. Measured mechanical properties were higher in paper sheets made from E. camaldulensis than M. sinclairii WB pulp. The highest tensile index values were observed with E. camaldulensis WB pulp treated with 5% HeOEs of S. alba (33.90 N·m/g) and M. grandiflora (33.76 N·m/g) compared to control (32.10 N·m/g); the highest tear index with 5% HeOE of S. alba (4.11 mN·m²/g) compared to control (3.32 mN·m²/g); and the highest burst index with 5% HeOE of S. alba (4.11 kPa·m²/g) compared to control (3.08 kPa·m²/g). The highest double-fold number value (9) was observed with E. camaldulensis WB pulp treated with 5% HeOEs of S. alba, M. azedarach, and M. grandiflora but with no significant difference compared to control treatment (8.33) or other HeOE treatments with E. camaldulensis WB pulp. Scanning electron microscope (SEM) examination showed clear inhibition of the growth of Aspergillus terreus with WB pulp paper discs of E. camaldulensis and M. sinclairii treated with HeOEs of M. azedarach, S. alba, and M. grandiflora at 3% and 5% compared to control treatment, while HeOEs at 5% concentration showed no growth of A. niger and A. terreus. The present findings establish that the HeOEs from M. azedarach, S. alba, and M. grandiflora at 3% and 5% are novel natural products that can be used as alternatives to improve the properties and antifungal activity of WB pulp produced from E. camaldulensis and M. sinclairii.

Phytochemical Compounds of Branches from P. halepensis Oily Liquid Extract and S. terebinthifolius Essential Oil and Their Potential Antifungal Activity

In the present study, the antifungal activity of wood treated with Pinus halepensis branch n-hexane oily liquid extract (OLE) and Schinus terebinthifolius branch essential oil (EO) was evaluated against the growth of four phytopathogenic fungi—Bipolaris oryzae, Fusarium oxysporum, Fusarium solani, and Rhizoctonia solani. Air-dried wood samples of Pinus roxburghii were autoclaved, and each wood received 100 µL of the concentrated oils from P. halepensis and S. terebinthifolius. The main compounds identified in S. terebinthifolius branch EO were terpinen-4-ol (18.25%), cis-β-terpineol (15.60%), γ-terpinene (12.46%), sabinene (9.83%), α-terpinene (8.56%), and 4-thujanol (6.71%), while the main compounds in P. halepensis branch HeO were 2-undecenal (22.25%), 4-hydroxy-10-methyl-3,4,7,8,9,10-hexahydro-2H-oxecin-2-one (8.43%), (Z)-2-decenal (6.88%), nonanal (5.85%), (2E)-2-decenal (4.65%), (E,E)-2,4-decadienal (4.41%), arachidonic acid methyl ester (4.36%), and 2-(7-heptadecynyloxy)tetrahydro-2H-pyran (4.22%). P. halepensis OLE at a concentration of 3% showed the highest inhibition percentage of fungal growth (IPFG) of B. oryzae, followed by S. terebinthifolius EO at 3% and 2%, with IPFG values of 80%, 74.44%, and 71.66%, respectively. At a concentration of 3%, branch oils from S. terebinthifolius and P. halepensis were found to have the highest IPFG values with 45.55% and 40.55%, respectively, against F. oxysporum growth. Moderate to weak activity was found against F. solani when S. terebinthifolius EO and P. halepensis OLE were applied to wood. EO and OLE-treated wood samples at 3% produced inhibitions of 54.44% and 41.11%, respectively, against R. solani.

Mass Spectroscopic Analysis, MNDO Quantum Chemical Studies and Antifungal Activity of Essential and Recovered Oil Constituents of Lemon-Scented Gum against Three Common Molds

The present study described the possibility of using wood-treated oil-fungicide of lemon-scented gum (Corymbia citriodora) from newly emerged leaves and unripened fruits against the infestation of Fusarium culmorum, Rhizoctonia solani and Penicillium chrysogenum. Air-dried wood samples of Melia azedarach were treated with the extracted oils from leaves and unripened fruits from C. citriodora. The main chemical constituents identified in the essential oil (EO) from leaves were citronellal (55.31%), citronellol (21.03%) and isopulegol (10.79%), while in unripened fruits were α-pinene (17.86%), eudesmol (13.9%), limonene (9.19%), γ-terpinen (8.21%), and guaiol (7.88%). For recovered oils (ROs), the major components from leaves were D-limonene (70.23%), γ-terpinene (13.58%), β-pinene (2.40%) and isopregol (2.23%), while, 4-terpineol (21.35%), cis-β-terpineol, (19.33%), D-limonene (14.75%), and γ-terpinene (7.42%) represented the main components in fruits. EOs from leaves and fruits at the amounts of 100, 50 and 25 µL showed the highest inhibition percentage (IP) of 100% against F. culmorum and P. chrysogenum compared to control treatment, while at the amounts of 100, and 50 µL showed 100% IP of R. solani. Wood treated with ROs from leaves and fruits showed IPs of 96.66% and 93.33%, respectively, against the growth of R. solani. The mass spectra of the main components of C. citriodora leaves and fruits’ EOs have been recorded in electron ionization mode at 70 eV and fragmentation has been reported and discussed. On the other hand, different quantum parameters such as the heat of formation, ionization energy total energy, binding energy, electronic energy and dipole moment using the modified neglect of diatomic overlap (MNDO) semi-empirical method have been calculated.

The Potential Antibacterial and Antifungal Activities of Wood Treated with Withania somnifera Fruit Extract, and the Phenolic, Caffeine, and Flavonoid Composition of the Extract According to HPLC

In the present study, Melia azedarach wood blocks treated with different acetone extract concentrations from Withania somnifera fruits are assessed for their antibacterial and anti-fungal activities. Wood blocks of M. azedarach treated with W. somnifera fruit extract at concentrations of 0, 1, 2, and 3% are evaluated for in vitro antimicrobial activity against five genbank accessioned bacterial strains—Agrobacterium tumefaciens, Dickeya solani, Erwinia amylovora, Pseudomonas cichorii, and Serratia pylumthica—and two fungi, namely, Fusarium culmorum and Rhizoctonia solani. Through HPLC analysis we find that the most abundant quantified phenolic and flavonoid compounds of acetone extract (mg/100 g) are salicylic acid (9.49), vanillic acid (4.78), rutin (4702.58), and myricetin (1386.62). Wood treated with the extract at 2% and 3% show no growth of A. tumefaciens, E. amylovora, and P. cichorii. Use of the extract at 3% causes inhibition of fungal mycelia of F. culmorum and R. solani by 84.07% and 67.03%, respectively. In conclusion, potent antifungal and antibacterial activity against plant pathogens is found when an acetone extract of W. somnifera fruits is applied to wood samples.

The Biofungicide Activity of Some Plant Essential Oils for the Cleaner Production of Model Linen Fibers Similar to Those Used in Ancient Egyptian Mummification

In this work, the essential oils (EOs) from Eriocephalus africanus leaf, Vitex agnus-castus leaf and fruit, Cymbopogon citratus leaf, and Rosmarinus officinalis leaf were used as antifungal agents against isolated Aspergillus flavus, Cladosporium cladosporioides, and Penicillium chrysogenum from an ancient Egyptian child’s mummy. The isolated fungi were used to colonize the samples of linen fibers. The best oil was used as a novel natural product for the cleaner production of model linen fibers similar to those used in ancient Egyptian mummification. Standard and original linen fibers were compared with the infected Linen samples using Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses. The FTIR revealed the changes in the molecular structure of the cellulose, hemicellulose, and lignin of the infected linen fibers. The cellulose crystallinity indices decreased to 64.61%, 52.69%, and 54.63% in the linen inoculated with A. flavus, C. cladosporioides, and P. chrysogenum compared to the control sample (72.08%), thereby affecting the chemical properties of the cellulose. The mycelia inhibition percentages of the three fungi reached 100% after the leaf EO from V. agnus-castus was applied, followed by C. citratus. The V. agnus-castus leaf EO applied at contraptions of 250, 500, 50, 1000, and 2000 µL/mL showed 100% inhibition for A. flavus and P. chrysogenum and reached 100% against C. cladosporioides at concentrations of 500, 750, 1000, and 2000 µL/mL. C. citratus leaf essential oil applied at concentrations of 500, 750, 1000, and 2000 µL/mL showed 100% inhibition to the growth of A. flavus and C. cladosporioides and reached 100% inhibition against the growth of P. chrysogenum at concentrations of 750, 1000 and 2000 µL/mL. This inhibition could be related to the main compounds of caryophyllene (23.13%), eucalyptol (20.59%), sabinene (β-thujene) (12.2%), γ-elemene (9%), and β-farnesene (6.14%) identified in V. agnus-castus leaf EO or due to the main compounds of β-citral (43.63%) and geranial (41.51%), as identified in the leaf EO of C. citratus by GC/MS. The morphological changes in the hyphae of the fungi were observed via SEM examination, where V. agnus-castus leaf EO, the best active oil, showed potent inhibition to fungi grown on the model linen fiber. In this way, the morphology and the structure of the hyphae were effectively changed. Our findings prove that the designed model linen fiber treated with V. agnus-castus leaf EO is able to preserve wrapping fibres and represents a novel natural alternative for effective fungicidal treatment.

Toxicological Activity of Some Plant Essential Oils Against Tribolium castaneum and Culex pipiens Larvae

In the present work, essential oils (EOs) from Schinus terebinthifolius (ripe and unripe fruits and leaves), Origanum majorana (air-dried aerial parts), and Psidium guajava (leaves) were assayed for their insecticidal activity against red flour beetle (Tribolium castaneum) and Culex mosquito larvae (Culex pipiens). Several components were identified in the EOs using Gas chromatography–mass spectrometry (GC/MS), of which Δ-3-carene (25.9%), γ-terpinene (19.4), and γ-elemene (7.1%) were the major ones in S. terebinthifolius ripe fruits, α-pinene (48.9%), germacrene D (12.9%), and α-thujene (7.7%) in S. terebinthifolius unripe fruits, γ-elemene (11.7%), spathulenol (10.1%), β-elemene (9.2%), and p-cymene (9.1%) in S. terebinthifolius leaves, α-pinene (25.5%), (E)-caryophyllene (15.7%), (E)-nerolidol (16.7%), and cedran-8-ol (8.8%) in P. guajava leaves, and terpinen-4-ol (21.7%), γ-terpinene (16.5%), and sabinene (10.1%) in O. majorana air-dried aerial parts. The lethal concentration (LC50) was calculated for tested EOs at different time periods (after 6, 12, 24, 48, and 72 h). After 6 h of treatment, the LC50 was 33.3 and 6.8 µg/L air for S. terebinthifolius ripe and unripe fruits, respectively, and >40 µg/L air for EOs of S. terebinthifolius leaves, O. majoranaair-dried aerial parts, and P. guajava leaves. After 24 h of treatment, the LC50 was 4.2, <2, 5, >40, and 6.1 µg/L air for EOs of S. terebinthifolius ripe fruits and leaves, O. majorana leaves, and P. guajava leaves, respectively. On the other hand, the LC50 values decreased when the exposed period was increased to 72 h, and were <2 µg/L air for EOs of S. terebinthifolius ripe fruits, unripe fruits, and leaves along with P. guajava leaves, respectively, and 37.912 for EO of O. majorana leaves. The LC50 value after 24 h of exposure of S. terebinthifolius unripe fruit EO was under 2 µg/L air, which means that the EO of S. terebinthifolius ripe fruit had a strong effect on adult T. castaneum adults compared to other tested EOs using the fumigation method. The present data confirm that the EOs of O. majorana leaves and S. terebinthifolius unripe fruits and leaves were more effective as larvicide than the EOs of S. terebinthifolius ripe fruits and P. guajava leaves on C. pipiens at a higher concentration (100 mg/L) when applied by the dipping method. EOs from S. terebinthifolius unripe or ripe fruits and leaves and P. guajava leaves were more effective as adulticide than EO of O. majorana leaves against T. castaneum when applied by the fumigant method.

Assessment of the Toxicity of Natural Oils from Mentha piperita, Pinus roxburghii, and Rosa spp. Against Three Stored Product Insects

Three natural oils extracted from Mentha piperita, Pinus roxburghii, and Rosa spp. were assessed in order to determine their insecticidal activity against the adults of three stored product insects: the rice weevil (Sitophilus oryzae L.), the lesser grain borer (Rhyzopertha dominica, Fabricius), and the red flour beetle (Tribolium castaneum, Herbst.). By Gas chromatography–mass spectrometry (GC/MS) analysis, the main compounds in the n-hexane oil from Rosa spp. were determined to be methyl eugenol (52.17%), phenylethyl alcohol (29.92%), diphenyl ether (7.75%), and geraniol (5.72%); in the essential oil from M. piperita, they were menthone (20.18%), 1,8-cineole (15.48%), menthyl acetate (13.13%), caryophyllene (4.82%), β-pinene (4.37%), and D-limonene (2.81%); and from the foliage of P. roxburghii, they were longifolene (19.52%), caryophyllene (9.45%), Δ-3-carene (7.01%), α-terpineol (6.75%), and γ-elemene (3.88%). S. oryzae and R. dominica were reared using sterilized wheat grains, and T. castaneum was reared on wheat flour mixed with yeast (10:1, w/w), all under laboratory conditions (27 ± 1 °C and 65% ± 5% Relative humidity (R.H). Two toxicity bioassays were used, as well as contact using thin film residues and fumigation bioassays. The results indicated that M. piperita caused a high toxicity for S. oryzae compared to other insects. High significant variations were observed between the tested M. piperita doses against the stored insects, and this natural material could be used to control insects that infect the grains. Also, the data indicated that the Rosa spp. oil had a low-toxicity effect against these insects compared to other oils. We recommend using natural oils against the stored weevils and petals, rather than the chemical agent, so as to serve human health.

Essential and Recovery Oils from Matricaria chamomilla Flowers as Environmentally Friendly Fungicides Against Four Fungi Isolated from Cultural Heritage Objects

Recovery oils, obtained from the hydro-distillation of the fresh flowers of Matricaria chamomilla, as well as essential oils, were studied for their environmental purposes in cultural heritage. These oils were assayed for their antifungal activity against the growth of four molds isolated from archaeological manuscripts (Aspergillus niger), museum gypsum board Antique (A. flavus), museum archaeological tissue (A. terreus), and museum organic materials (Fusarium culmorum) of cultural heritage objects. Oils were applied to inhibit the growth of fungi at amounts of 25, 50, 75 and, 100 µL/mL, and compared with negative controls (0 µL/mL) or positive controls (Sertaconazol 3g/L). Using GC/MS analysis, the main chemical compounds identified in the essential oil were (Z)-β-farnesene (27%), D-limonene (15.25%), and α-bisabolol oxide A (14.9%), while the compounds identified in the recovery oil were α-bisabolol oxide A (18.6%), d-limonene (8.82%), and α-bisabolol oxide B (7.13%). A low amount of chamazulene was observed in both essential and recovery oils, with amounts of 0.73% and 3.50%, respectively. Recovery oil, at a concentration of 75 and 100 µL/mL, showed fungal mycelial inhibition (FMI) percentage for the growth of A. niger, with values of 78% and 85%, respectively. At a concentration of 100 µL/mL, both oils showed 100% FMI of A. terreus. Oils showed weak activity against the growth of A. flavus. Essential oils at 100 µL/mL had good activity against the growth of F. culmorum, with FMI of 86.6%. The results suggest the potential use of essential and recovery oils from M. chamomilla fresh flowers as environmentally friendly bio-fungicides.

Yield, Phytochemical Constituents, and Antibacterial Activity of Essential Oils from the Leaves/Twigs, Branches, Branch Wood, and Branch Bark of Sour Orange (Citrus aurantium L.)

In the present work, essential oils (EOs) extracted from different parts of sour orange Citrus aurantium (green leaves/twigs, small branches, wooden branches, and branch bark) were studied through gas chromatography coupled with mass spectrometry (GC/MS). Furthermore, the EOs in the amounts of 5, 10, 15, 20, and 25 µL were studied for their antibacterial activity against three pathogenic bacteria, Agrobacterium tumefaciens, Dickeya solani, and Erwinia amylovora. The main EO compounds in the leaves/twigs were 4-terpineol (22.59%), D-limonene (16.67%), 4-carvomenthenol (12.84%), and linalool (7.82%). In small green branches, they were D-limonene (71.57%), dodecane (4.80%), oleic acid (2.72%), and trans-palmitoleic acid (2.62%), while in branch bark were D-limonene (54.61%), γ-terpinene (6.68%), dodecane (5.73%), and dimethyl anthranilate (3.13%), and in branch wood were D-limonene (38.13%), dimethyl anthranilate (8.13%), (-)-β-fenchol (6.83%), and dodecane (5.31%). At 25 µL, the EO from branches showed the highest activity against A. tumefaciens (IZ value of 17.66 mm), and leaves/twigs EO against D. solani and E. amylovora had an IZ value of 17.33 mm. It could be concluded for the first time that the wood and branch bark of C. aurantium are a source of phytochemicals, with D-limonene being the predominant compound in the EO, with potential antibacterial activities. The compounds identified in all the studied parts might be appropriate for many applications, such as antimicrobial agents, cosmetics, and pharmaceuticals.