Exploring Ecological Alternatives for Crop Protection Using Coriandrum sativum Essential Oil

Essential oils (EOs) are a natural source of active compounds with antifungal, antimycotoxigenic, and herbicidal potential, and have been successfully used in organic agriculture, instead of chemical compounds obtained by synthesis, due to their high bioactivity and the absence of toxicity. The aim of this study was to highlight the importance of Coriandrum sativum essential oil (CEO) as a potential source of bioactive constituents and its applications as an antifungal and bioherbicidal agent. The CEO was obtained by steam distillation of coriander seeds and GC-MS technique was used to determine the chemical composition. Furthermore, in vitro tests were used to determine the antifungal potential of CEO on Fusarium graminearum mycelia growth through poisoned food technique, resulting in the minimum fungistatic (MCFs) and fungicidal concentrations (MCFg). The antifungal and antimycotoxigenic effect of CEO was studied on artificially contaminated wheat seeds with F. graminearum spores. Additionally, the herbicidal potential of CEO was studied by fumigating monocotyledonous and dicotyledonous weed seeds, which are problematic in agricultural field crops in Romania. The in vitro studies showed the antifungal potential of CEO, with a minimum concentration for a fungistatic effect of 0.4% and the minimum fungicidal concentration of 0.6%, respectively. An increase in the antifungal effects was observed in the in vivo experiment with F. graminearum, where a mixture of CEO with Satureja hortensis essential oil (SEO) was used. This increase is attributed to the synergistic effect of both EOs. Moreover, the synthesis of deoxynivalenol (DON)-type mycotoxins was found to be less inhibited. Hence, CEO has shown an herbicidal potential on weed seeds by affecting inhibition of germination.


Introduction
Crop contamination with fungal species during the vegetation period and postharvest, under inadequate storage conditions, such as high air humidity and poor or absent ventilation, is a common issue and results in significant economic losses [1]. Replacement of synthetic In addition, in light of recent research on the synergy of EOs [19], an increase in CEO performance was sought by the addition of Satureja hortensis essential oil (SEO) in various ratios.

The Chemical Composition of CEO
The mean value of CEO yield was found to be low (0.6%), this being in accordance with previously reported studies on the amount of CEOs in seeds in the range from 0.2% to 1.5% [22]. The GC-MS profiles of CEO chemical composition and concentration (in order of elution) are listed in Table 1. In CEO, twenty-one compounds were identified comprising 99.76% of the total EO composition. Monoterpene hydrocarbons (MH) were identified at 39.204%, while monoterpene oxygenates (MO) represented 60.556% of the total compounds. The chromatographic profile of CEO showed that linalool was the major compound, at 45.387%, followed by α-pinene, at 11.626%, and D-limonene, at 9.628% (Table 1). Other compounds identified with a concentration higher than 5% were p-cymene (8.00%), camphor (6.016%), and γ-terpinene (5.236%).

The Antifungal Activity Effectiveness
The CEO added in the culture medium inhibited the growth of new F. graminearum mycelium starting at a concentration of 0.04%. As can be seen in Figure 1, the new mycelial growth (NMG) values vary between 2.9 cm 2 , corresponding to the experimental sample treated with 0.02% CEO, and 0.2 cm 2 for 0.3% CEO. On the other hand, in the case of a sample with 0.2% CEO, the NMG value exceeded the NMG control value by 0.4 cm 2 . It seems that the presence of reduced amounts of CEO stimulates the F. graminearum mycelia growth. Only from 0.04% CEO did we observe a decrease in the mycelinum area. The decrease was observed progressively with increasing CEO concentration. Thus, at 0.3% CEO, the NMG value reached only 0.2 cm 2 . As shown above, 0.4% CEO corresponded to minimal fungistatic effect (MCFs). The minimum concentration for fungicidal effect (MCFg) corresponded to 0.6% CEO. The MCFg value was confirmed only after transfers of mycelial disks and that the fungus hyphae had not been revived. This concentration was used for in vivo antifungal testing of the wheat kernel by fumigation with CEO. The antifungal effect of the CEO could be attributed to the linalool compound, which was reported to have an antibacterial effect [31], and is responsible for the flavor of the coriander [22]. The previous studies showed that CEO has an excellent antifungal activity against seed borne pathogens of paddy: Pyricularia oryzae, Bipolaris oryzae, Alternaria alternata, Tricoconis padwickii, Drechslera tetramera, D. halodes, Curvularia lunata, Fusarium moniliforme, and F. oxysporum. The fungicidal effect of CEO against F. oxysporum was 100% at a level of 2000 µg/mL and 25.55% at 500 µg/mL [22]. Zare-shehneh et al. (2014) showed that the MCFs against P. lilacinum and A. niger were 67.8 and 62.1 mg/mL, respectively [32].

Effect of Augmented CEO against the Growth of Mycotoxigenic Fungi and Deoxynivalenol (DON) Accumulation
Recently, the synergistic effects of EO mixtures, with other EOs [34] or standard antimicrobial agents [35] have been reported. Both studies have proven that mixtures enhance the desired properties significantly. The seed contamination index (ICK, %) for all the fungal species identified in the case of wheat kernels fumigated with CEO and CEO/SEO mixture after 7 and 14 days, respectively, from treatment are presented in Figure 2. Consequently, variable amounts of linalool in the CEO, suggests the necessity of the addition of a further plant oil extract [33]. In this way, a variety of active components would ensure the inhibition of pathogen or decay microorganisms, which cannot develop a resistance, and antimicrobial or antifungal efficiency.

Effect of Augmented CEO against the Growth of Mycotoxigenic Fungi and Deoxynivalenol (DON) Accumulation
Recently, the synergistic effects of EO mixtures, with other EOs [34] or standard antimicrobial agents [35] have been reported. Both studies have proven that mixtures enhance the desired properties significantly. The seed contamination index (ICK, %) for all the fungal species identified in the case of wheat kernels fumigated with CEO and CEO/SEO mixture after 7 and 14 days, respectively, from treatment are presented in Figure 2.
Recently, the synergistic effects of EO mixtures, with other EOs [34] or standard antimicrobial agents [35] have been reported. Both studies have proven that mixtures enhance the desired properties significantly. The seed contamination index (ICK, %) for all the fungal species identified After 7 days of fumigation, a significant decrease in the number of wheat kernels contaminated with Fusarium graminearum was observed when compared to the control experiment. The lowest value recorded in the CS1 mixture was an ICK value of 10%. This suggests a synergistic antifungal effect of CEO with SEO in controlling Fusarium contamination in the studied wheat kernels. Rhizopus sp., along with F. graminearum, are tolerant to EO vapors. Hence, the presence of fungal contamination at 7 days after fumigation in all samples studied, regardless of the ratios, was observed.
After 14 days of fumigation, a decrease from 60% to 40% of the ICK value for Fusarium in the presence of the CEO was observed. At the same time, the appearance of the Alternaria sp., denotes the exhaustion of the antifungal effect of EOs, probably due to loss of antifungal compounds by volatilization.
Other studies proved that the CEO has an antifungal effect at various concentrations over Alternaria alternata, Stachybotrys chartarum, Cladosporium cladosporioides, and Aspergillus niger [8].
The antifungal activity effect of coriander extracts was also proven by Zardini et al. (2012) by studying its effects on P. lilacinum and A. niger [9].
The use of EOs for grain storage by fumigation is a popular technique nowadays. Thus, Syzygium aromaticum and Vatica diospyroides EOs have proven to be very effective against Aspergillus flavus on maize seeds fumigated with 10 µl/L, even if the dose was found to subsequently affect germination capacity of the seeds [36].
In our research, contamination with Fusarium did not decrease after 14 days, highlighting that the treatment effect of CEO in fungal control, even by mixing with SEO, is maintained for only 7 days, after which a second treatment is needed. Additionally, the samples fumigated with CEO alone or combined with SEO in the CS1 and CS2 mixtures, and also in the control sample, the appearance of Aspergillus, Mucor, and Cladosporium can be noticed. Promising results regarding the use of CEOs in mixtures has proven antifungal protection by mixing 800 ppm CEO with 250 ppm Cinnamomum cassia, from the Lauraceae family against Byssochlamys fulva [23]. In the case of the CS3 mixture, a minimal fungus load with Fusarium sp. and Alternaria sp. correlated with economic efficiency, which recommends this conceptual solution for the fungal protection of cereals in storage, is noted. SEO, used as additional compounds in our study, contains, as major compounds, o-cymene (30.728%), thymol (25.746%), and γ-terpinene (11.821%). Other compounds were identified in concentrations lower than 10%. The group of Katar et al. (2017) reported γ-terpinene and carvacrol as major components and highlighted that the climatic and geographic conditions influence the chemical composition of SEO [37].
The synergistic or antagonistic effects generated by the presence of chemical compounds in the two EO compositions may be responsible for the different biological action of CEO/SEO mixtures when compared to the pure CEO. The inhibitory effect of CEO oil is due to oxygenated monoterpenes. The experimental results are shown in Figure 3.  The DON content in the control sample after 14 days was 0.269 ppm, with the decrease in the mycotoxigenic load being 4.6%. This decrease is in line with the evolution of F. graminearum, whose development decreases over time with the occurrence of other fungal species, such as Alternaria sp. and Mucor sp. in wheat samples. The treatment with CEO, led to a considerably decreased DON content, compared with the control (39%) after 7 days. This decrease was even more pronounced after 14 days (81.04%). The treatment with CS leads to a similar profile to CEO treatment, however, the inhibition effectiveness of DON formation is lower compared to CEO treatment. In the case of treatment with CS mixture, the reduction in DON contamination of samples when compared to the control varied between 1.41% and 26.95%. Furthermore, the CS mixture showed the optimal protection against the synthesis of DON mycotoxin.
It was observed that there is no linear dependence between the CS concentration and the DON content. The more concentrated mixtures (CS2) led to a higher mycotoxigenic load (0.278 ppm) compared to the more diluted (0.216 ppm) CS3 sample. The rate of growth inhibition after 14 days of CEO treatment and mixtures varied between 81.04%, in the case of CEO treatment, and 29.44% for the cereals treated with the CS2 mixture. It is important to emphasize that the SEO addition to the CEO did not induce the mycotoxins synthesis, as the inhibition effects of DON synthesis were lower for CS variants. Similar results on the inhibition of DON production with EO treatment belonging to Lamiaceae family have been previously reported, which showed that, after 22 days of treatment with EOs, DON was undetectable in wheat samples [17,38].

The Herbicidal Potential Assay
The herbicidal potential of CEO has been tested for weed seeds using the fumigation technique to inhibit germination. The herbicidal potential has been observed on monocotyledonous weed seeds, The DON content in the control sample after 14 days was 0.269 ppm, with the decrease in the mycotoxigenic load being 4.6%. This decrease is in line with the evolution of F. graminearum, whose development decreases over time with the occurrence of other fungal species, such as Alternaria sp. and Mucor sp. in wheat samples. The treatment with CEO, led to a considerably decreased DON content, compared with the control (39%) after 7 days. This decrease was even more pronounced after 14 days (81.04%). The treatment with CS leads to a similar profile to CEO treatment, however, the inhibition effectiveness of DON formation is lower compared to CEO treatment. In the case of treatment with CS mixture, the reduction in DON contamination of samples when compared to the control varied between 1.41% and 26.95%. Furthermore, the CS mixture showed the optimal protection against the synthesis of DON mycotoxin.
It was observed that there is no linear dependence between the CS concentration and the DON content. The more concentrated mixtures (CS2) led to a higher mycotoxigenic load (0.278 ppm) compared to the more diluted (0.216 ppm) CS3 sample. The rate of growth inhibition after 14 days of CEO treatment and mixtures varied between 81.04%, in the case of CEO treatment, and 29.44% for the cereals treated with the CS2 mixture. It is important to emphasize that the SEO addition to the CEO did not induce the mycotoxins synthesis, as the inhibition effects of DON synthesis were lower for CS variants. Similar results on the inhibition of DON production with EO treatment belonging to Lamiaceae family have been previously reported, which showed that, after 22 days of treatment with EOs, DON was undetectable in wheat samples [17,38].

The Herbicidal Potential Assay
The herbicidal potential of CEO has been tested for weed seeds using the fumigation technique to inhibit germination. The herbicidal potential has been observed on monocotyledonous weed seeds, Echinochloa crus-galli (EGAL), and has been extended to wheat seeds (WHEAT). Among dicotyledonous weeds, this study focused on the problematic weeds known for their aggressiveness and competitiveness in the crop field, i.e., Amaranthus retroflexus (ARET) and Chenopodium album (CALB). To the best of our knowledge, this work presents the first bio-herbicidal study of CEO from Romania and the results are displayed in Figure 4. The rate of inhibition of weed germination in the case of fumigation with CEOs in different concentrations (0.3%, 0.6%, and 1%) varied between 65% and 100%. At 1% CEO concentration, the herbicidal effect was maximal for all weed seeds. Chenopodium album showed the highest sensitivity among the tested weeds, with 75% and 95% inhibition rate for the CEO at 0.3% and 0.6%, respectively. The effect of CEO on wheat seed germination presents various germination inhibition behavior with values between 66% and 83%. The maximum inhibition was recorded at 1% CEO. Chenopodium album showed the highest sensitivity among the tested weeds, with 75% and 95% inhibition rate for the CEO at 0.3% and 0.6%, respectively. The effect of CEO on wheat seed germination presents various germination inhibition behavior with values between 66% and 83%. The maximum inhibition was recorded at 1% CEO. The CS mixture revealed a 100% germination inhibition effect for all three seed types analyzed when used in ratios of 10% CEO + 2% SEO. The CS2 mixture presented a 100% inhibition of germination of CALB and EGAL, and 77.8% of ARET. The lower concentration, CS3, inhibited the seed germination with values between 44% and 80%. In the case of wheat seeds, germination was inhibited 78.9-89.5%, depending on the CS concentration, see Figure 5. The variation of the herbicidal effect of EOs on seeds germination may be due to the different seed coat layers and their permeability [39]. The CS mixture revealed a 100% germination inhibition effect for all three seed types analyzed when used in ratios of 10% CEO + 2% SEO. The CS2 mixture presented a 100% inhibition of germination of CALB and EGAL, and 77.8% of ARET. The lower concentration, CS3, inhibited the seed germination with values between 44% and 80%. In the case of wheat seeds, germination was inhibited 78.9-89.5%, depending on the CS concentration, see Figure 5. The variation of the herbicidal effect of EOs on seeds germination may be due to the different seed coat layers and their permeability [39]. Our study confirms previous results with regards to the herbicidal effect of EOs, which would recommend them as natural herbicides in organic farming. Regarding the allelopathic effect of EOs in connection with wheat germination, previous studies have shown that wheat cultivars were less affected compared to weed species, suggesting the possibility to use these natural compounds-in proper doses-as bioherbicides for weed control [40,41]. However, the germination inhibition rate of rosemary EO for wheat cultivars ranged between 10.3% and 78.5%, when the concentration dose was in the range of 2 to 16 µL.
Until now, there has been no studies reporting on the herbicidal effect of the CEO. The allelopathic effect of EOs extracted from different medicinal and aromatic plants was reported by Paudel and Gupta (2009) against seed germination of Parthenium hysterophorus L., a noxious weed [42]. The results have shown that lemongrass at 8 mL/L, and cinnamomum and eucalyptus oil at 12 mL/L, inhibited the germination of Parthenium seeds completely. Other studies reported that cinnamon EO exhibited the stronger inhibition effect on the seed germination of redroot pigweed and wild mustard, while peppermint oil has been the most effective in inhibiting ryegrass seed germination [43].
Oregano and rosemary EOs exhibited efficient control against the development of Avena sterilis and Sinapis arvensis weeds, commonly found in the wheat growing field. Even an application of 2 µL EO had a harmful effect. The inhibition rate of S. arvensis was 100% when 4 µL of oregano EO was applied, while the inhibition rate of A. sterilis was 64.6% with the application of a 16 µL dose of rosemary oil. Furthermore, the inhibition rates increased with increased oil concertation [40].  Our study confirms previous results with regards to the herbicidal effect of EOs, which would recommend them as natural herbicides in organic farming. Regarding the allelopathic effect of EOs in connection with wheat germination, previous studies have shown that wheat cultivars were less affected compared to weed species, suggesting the possibility to use these natural compounds-in proper doses-as bioherbicides for weed control [40,41]. However, the germination inhibition rate of rosemary EO for wheat cultivars ranged between 10.3% and 78.5%, when the concentration dose was in the range of 2 to 16 µL.

Extraction and GC-MS Characterization of CEO
Until now, there has been no studies reporting on the herbicidal effect of the CEO. The allelopathic effect of EOs extracted from different medicinal and aromatic plants was reported by Paudel and Gupta (2009) against seed germination of Parthenium hysterophorus L., a noxious weed [42]. The results have shown that lemongrass at 8 mL/L, and cinnamomum and eucalyptus oil at 12 mL/L, inhibited the germination of Parthenium seeds completely. Other studies reported that cinnamon EO exhibited the stronger inhibition effect on the seed germination of redroot pigweed and wild mustard, while peppermint oil has been the most effective in inhibiting ryegrass seed germination [43].
Oregano and rosemary EOs exhibited efficient control against the development of Avena sterilis and Sinapis arvensis weeds, commonly found in the wheat growing field. Even an application of 2 µL EO had a harmful effect. The inhibition rate of S. arvensis was 100% when 4 µL of oregano EO was applied, while the inhibition rate of A. sterilis was 64.6% with the application of a 16 µL dose of rosemary oil. Furthermore, the inhibition rates increased with increased oil concertation [40].

Extraction and GC-MS Characterization of CEO
Coriandrum sativum seeds were purchased from the Agricultural Research Development Resort Secuieni, Neamt County, Romania (46 • 51 45" N 26 • 49 42" E). The seeds of Coriandrum sativum were ground with Grindomix Retsch GM 2000 laboratory mill (Haan, Germany) and 300 g of a homogenous sample were used for steam distillation for 2.0 h, using Clevenger-type equipment (Timisoara, Romania), according to the European Pharmacopoeia (1975) [44]. The obtained oil was stored at 2-4 • C until the antifungal and herbicidal analysis.
The extraction yield of the CEO was calculated using the following formula: % yield = [amount of CEO (g)/amount of seeds (g)] × 100.
The chemical characterization of CEO was done using the gas-chromatograph equipment with mass spectrometer (GC-MS) Shimadzu QP 2010Plus with a capillary column with the characteristics: AT WAX 30 m × 0.32 mm × 1 µm. The carrier gas used was helium with a flow rate of 1 mL/min. The settings used for the separation was: 40 • C for 1 min, a rate of 5 • C/min to 210 • C for 5 min. Injector and ion source temperatures were 250 • C and 220 • C, respectively. The injection volume was 1 µL at a ratio of 1:50.
The identification of the chemical composition of CEO volatile compounds was performed in accordance with other specialized studies using 3 alternative methods: comparison with NIST 5 Wiley 275 libraries database, calculation of the linear retention index (LRI), and comparison with LRI from the literature data. The linear retention indices (LRIs) were determined in relation to a homologous series of n-alkanes (C8-C24) under the same operating conditions and calculated according to Van den Dool and Kratz formula and compared with the literature data [30,45].

In Vitro Antifungal Activity Assay
The in vitro study aimed to determine the minimum CEO concentration with impact on mycelia growth, through the "poisoned food technique" [46]. In order to study the fungal mycelium's ability to grow and regenerate, a defined amount of CEO was added to the culture medium. The culture medium used was YCGA (yeast extract glucose chloramphenicol agar, 95765, Sigma-Aldrich), with the oil being added in different quantities to achieve the following concentrations: 0% (control), 0.02%, 0.04%, 0.06%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.6% CEO (v/v). Minimum concentration with fungistatic effect (MCFs) is defined as the concentration starting from which the fungal growth is inhibited. By transferring the fungus to a fresh medium (without EO addition) a revival of hyphae and the mycelium growth is observed. Minimum concentration with fungicidal effect (MCFg) is defined as the concentration from which the fungal growth is inhibited and by transferring the inoculum to a fresh medium there is no hyphae or mycelium revival. 9 mm disks of 4-day-old F. graminearum mycelium were transferred to the YCGA medium with different concentrations of CEO (three of each concentration taken as repetitions). Incubation was done under alternate light/dark conditions 12 h/12 h. On the 5th day, observations were made by measuring two perpendicular diameters for each new fungal growth. The new mycelia growth (NMG) was calculated using the following formula: where DM is the diameter of finally mycelium growth (mm) and IMD is the initial mycelium disc (0.63 mm 2 ). The experiment for antifungal activity assay was conducted twice.

In Vivo CEO Potential against Mycotoxigenic Fungi and DON Accumulation
Organic wheat kernels, Antille cultivar, harvested in 2016 were used to evaluate the effect of CEO on the growth of mycotoxin fungi and the synthesis of deoxynivalenol mycotoxin. Therefore, the fumigation technique of wheat grain in sealed flasks (Schnelldorf, Germany) was used. Firstly, the kernels were artificially inoculated with an F. graminearum spore suspension with 2 × 10 6 CFU/mL certified with Bürker-Türk hemocytometer chamber BLAUBRAND (Wertheim, Germany). After 2 days, 50 g of wheat kernels samples were distributed in flasks lined with filter paper to which 5 mL of the studied oil treatment variant were added. The flasks were hermetically sealed and placed at 20-22 • C, in the dark.
The different ratios used for the fumigation of kernel were: CEO (0.6%, v/v), CS1 (CEO 10% + SEO 2%), CS2 (CEO 1% + SEO 0.2%), and CS3 (0.5% + SEO 0.1%). CS1, CS2, and CS3 were achieved by mixing EOs in volume ratios (v/v). After 7 and 14 days, respectively, the colonization of fumigated wheat grains was evaluated by placing 10 wheat kernels from each ratio on CYGA medium in Petri dishes incubated on day/night regime at 22 + 2 • C. After 4 days, the index colonization value of wheat kernels (ICK) was determined for each treatment [48]: where NCK is the number of contaminated kernels with one fungus species/treatment and NTK is the number of total kernels used on treatment. Assay of DON content was performed by the immunoenzymatic method (ELISA) after 7 and 14 days of seed fumigation in the presence of the studied EOs. Sample preparation was carried out according to the manufacturer's instructions for DON analysis in cereals (R-Biopharm) using an ELISA 96 reader (PR-1100, Bio-Rad Laboratories, Swindon, UK). Each sample, including standards, was analyzed twice. The average content of DON (ppm) initially determined in the wheat samples was 0.464 ppm; the sample humidity was 12.4% for water activity of a w = 0.9.

The Herbicidal Potential Assay
Weed seeds of Amaranthus retroflexus (ARET), Chenopodium album (CALB), and Echinochloa crus-galli (EGAL) were obtained from the seeds collection of the Department of Herbology, Faculty of Agriculture Timisoara. Seed samples were sterilized using a sodium hypochlorite solution (hypochlorite/water 1:9) for 3 min. Subsequently, the seeds were washed 3 times with distilled water for 3 min each time. A total of 10 seeds from each species were placed in a Petri dish, in layers separated by thin filter paper. Then, the seeds were treated with 6 mL of CEO (v/v) in the following concentrations: 0.3%, 0.6%, and 1%. To study the inhibition potential on germination of the weed seeds, the following mixtures of 3 mL CEO (v/v) + 3 mL SEO (v/v) were used: CS1 (CEO 10% + SEO 2%), CS2 (CEO 1% + SEO 0.2%), and CS3 (0.5% + SEO 0.1%). CS1, CS2 and CS3 were achieved by mixing EOs in volume ratios (v/v). Additionally, a control experiment was used, utilizing only distilled water (6 mL). To prevent the water loss, the Petri dishes were sealed with adhesive tape. The Petri dishes were kept at 25 • C in darkness and verified daily and on the 7th day the inhibition was evaluated. Each treatment, including the control, was repeated three times (in total 36 Petri dishes were used).

Statistical Analysis
The experimental assays were repeated twice (Section 3.1, Section 3.2, Section 3.3) and thrice (3.4). The results are presented as the mean ± standard deviation (SD). Statistical processing of data was performed using Microsoft Excel 2010. Significant statistical differences of investigated parameters were determined by t-Test: two-sample assuming unequal and equal variances at p < 0.05, after analysis of variance (ANOVA one-way).

Conclusions
In vitro assays concerning the growth of the phytopathogen fungus F. graminaerum with CEO added in different concentrations reveals the high antifungal potential of this oil, where the minimum concentration with fungistatic effect is 0.4% and the minimum fungicidal concentration 0.6% CEO. The association of CEO with SEO leads to an enhanced antifungal effect, as shown in the in vivo experiment for F. graminearum. Simultaneously, lesser amounts of DON, determined after 14 days, lead to the conclusion that the chemical compounds of EOs exhibit an antagonistic effect on the synthesis of DON-type mycotoxins. Applying the CEO to weed seeds by fumigation reveals the herbicidal potential of this EO, and the effect is amplified by mixing CEO with SEO.
In conclusion, the current study shows the potential of coriander essential oil as an antifungal and herbicidal agent, either as a standalone or in mixtures with SEO. Furthermore, it could be shown that the herbicidal effect and weed seed germination inhibition of CEO is enhanced due to the synergistic effect of the chemical components. Therefore, the CEO used alone or in mixtures with other EOs could be a useful alternative for organic farming.

Conflicts of Interest:
The authors declare no conflicts of interest.