1. Introduction
The origin of the banana is from India, Asia, it is an exotic and climatic fruit known as cambur, gualele, guineo, musacea, platano. In Ecuador, in El Oro province, Machala, has led exports since 1910 to the United States, Peru, and Chile, highlighting its quality, which is unmatched by fruits offered at lower prices from other countries [
1]. Currently it is the largest exporter of banana with internationally recognized quality product with a productivity of 1500 boxes per hectare per year, it is consumed when the peel is yellow, being an important source of vitamins, potassium, carbohydrates, and minerals [
2]. The rot in the banana increases in transport and the fungal growth decreases the quality of the fruit after harvest and produces the rot of the crown, known as “Crown rot” caused mainly by
Colletotrichum spp. [
3].
Oregano has bioactive compounds such as carvacrol, thymol, phenolic acids that have antimicrobial properties, antioxidants, cinnamon has cinnamaldehyde, eugenol, flavonoids that has anti-inflammatory, antioxidant, glucose regulation potential and the clove has Eugenol, acetyl eugenol, flavonoids acting as analgesic, antimicrobial, antioxidant [
4,
5]. Cinnamon essential oil was used as a bioactive compound to extend the lifetime of the strawberry as a post-harvest treatment [
6].
Basil has bioactive compounds such as eugenol, Rosmarinus acid, flavonoids that generates antioxidant, anti-inflammatory properties, thyme has thymol, carvacrol, flavonoids that generates antibacterial properties, antioxidant, enhances digestion and rosemary acid Rosmarinus, carnosol, flavonoids with antioxidative, anti-inflammatory, potential neuroprotective effect [
7,
8,
9].
The Ascomycetes family includes the genus of fungi
Cladosporium spp. and are commonly found in indoor and outdoor environments, are microscopically distinguished by having septate hyphae and conidia in groups or chains, the conidia are black, olive green, or sometimes brown, and frequently form in chains, are globose or ellipsoidal in shape. the hyphae are dark, branched, septate, and have a rough, cottony, or velvety texture. They may be plant pathogens, sometimes affect humans causing respiratory problems and allergies, are used in biodegradation, although they do not have significant industrial applications [
10,
11].
Lasiodiplodia spp. causes rot in fruit crops and is another type of fungus that is part of the Ascomycetes, the conidia are spherical in shape and occasionally form in chains, the hyphae are septate and frequently contain conidia in their spores, the texture may be cottony or velvety, with colors ranging from brown to black, and microscopically, conidia in spores and septate hyphae can be observed. The main impact of this fungus is on fruits and crops, causing diseases such as fruit rot. Its impact on agriculture is significant, although it is not frequently used in biotechnology [
12,
13].
Anthracnose is a common disease in many plants and is caused by various fungal pathogens, including those in the genera
Colletotrichum spp., is classified within the Ascomycetes, microscopically the conidia appear in clusters or groups and have a cylindrical or ellipsoidal shape, the hyphae usually have conidia in their cluster and are septate, the texture may be velvety or cottony, and the color may be pink, red or orange. It is used to control pests in agriculture and is used in biopesticides [
3,
9]. Studies are being conducted on antifungal activity (
in vitro) of plant extracts for the control of anthracnosis [
14].
Plant diseases such as wilt and root rot are caused by
Fusarium spp., some species produce mycotoxins that are harmful to animals and humans. It is a fungus of the Ascomycetes or Basidiomycetes families, the conidia may be white, pink, red, or purple, are elongated, and frequently appear in chains. Macroconidia and microconidia can be observed in the septate hyphae, and the texture may be cottony, velvety, or powdery [
15,
16].
Aspergillus spp. is found in food production, are used in the production of organic acids, enzymes and antibiotics, produce aflatoxins, which are toxic and carcinogenic, may also be opportunistic pathogens that infect people with weakened immune systems, are of the Ascomycetes family, microscopically, the conidia may be in chains or clusters, septate hyphae and the mycelium may be dense and abundant, the colonies may be green, black, white and yellow and the texture may be smooth, velvety, or cottony [
17,
18].
5. Conclusions
During the characterization process, the fungal strains were assessed and ranked based on their severity, from the most severe to the least severe. This ranking was determined through of an evaluation of the analysis in vivo report: Colletotrichum spp., Lasiodiplodia spp., Aspergillus spp., Fusarium spp. y Cladosporium spp. The in vitro antifungal activity analysis reveals that a concentration of 400 ppm of cinnamon essential oil is effective in inhibiting the growth of all five fungal species examined.
In the in vitro study to evaluate the efficacy of essential oils, cinnamon was effective at 400 ppm, thyme at 600 ppm, and clove at 1000 ppm, while basil and rosemary did not inhibit the growth of the analyzed pathogens. Specifically: Colletotrichum spp. was controlled with 200 ppm of oregano, thyme, 400 ppm of cinnamon, and 1000 ppm of clove. Lasiodiplodia spp. was controlled with 200 ppm of cinnamon, oregano, 600 ppm of thyme, and 1000 ppm of clove. Aspergillus spp. was controlled with 200 ppm of cinnamon, oregano, 600 ppm of clove, basil, and thyme. Fusarium spp. was controlled with 200 ppm of cinnamon, thyme, 800 ppm of clove, and oregano. Cladosporium spp. was controlled with 200 ppm of oregano, thyme, 400 ppm of cinnamon, clove, 600 ppm of basil, and 800 ppm of rosemary.
Figure 1.
Preparation of the amended medium with chloramphenicol (0.5 g/L), to obtain pure fungi responsible for the rot present in banana peels.
Figure 1.
Preparation of the amended medium with chloramphenicol (0.5 g/L), to obtain pure fungi responsible for the rot present in banana peels.
Figure 2.
Preparation of the initial dilution containing the microorganisms causing banana rot.
Figure 2.
Preparation of the initial dilution containing the microorganisms causing banana rot.
Figure 3.
Preparation of serial dilutions for plating 10µL on amended PDA medium.
Figure 3.
Preparation of serial dilutions for plating 10µL on amended PDA medium.
Figure 4.
Diagram for obtaining a concentration of 106 conidia/mL of each inoculum.
Figure 4.
Diagram for obtaining a concentration of 106 conidia/mL of each inoculum.
Figure 5.
Inoculation of the fungi with a concentration of 106 conidia/mL.
Figure 5.
Inoculation of the fungi with a concentration of 106 conidia/mL.
Figure 6.
Preparation scheme of the medium with established essential oil concentrations.
Figure 6.
Preparation scheme of the medium with established essential oil concentrations.
Figure 7.
Fungal growth (cm) for 6 weeks in 20 banana samples inoculated with Cladosporium spp., Lasiodiplodia spp. Colletotrichum spp., Fusarium spp. and Aspergillus spp., stored at 13°C and 95% HR.
Figure 7.
Fungal growth (cm) for 6 weeks in 20 banana samples inoculated with Cladosporium spp., Lasiodiplodia spp. Colletotrichum spp., Fusarium spp. and Aspergillus spp., stored at 13°C and 95% HR.
Figure 8.
In vitro growth analysis of Cladosporium spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 8.
In vitro growth analysis of Cladosporium spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 9.
In vitro growth analysis of Lasiodiplodia spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 9.
In vitro growth analysis of Lasiodiplodia spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 10.
In vitro growth analysis of Colletotrichum spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 10.
In vitro growth analysis of Colletotrichum spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 11.
In vitro growth analysis of Fusarium spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 11.
In vitro growth analysis of Fusarium spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 12.
In vitro growth analysis of Aspergillus spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 12.
In vitro growth analysis of Aspergillus spp. on PDA medium with basil, cinnamon, clove, oregano, rosemary, and thyme essential oils at 200, 400, 600, 800, and 1000 ppm, stored at 25°C (n=4).
Figure 13.
Fungi isolated and purified from banana peel rot, inoculated on selective medium (PDA with chloramphenicol), and stored on PDA at a 25°C in the incubator, (a) strain of Cladosporium spp., (b) Lasiodiplodia spp., (c) Colletotrichum spp., (d) Fusarium spp. spp. and (e) Aspergillus spp..
Figure 13.
Fungi isolated and purified from banana peel rot, inoculated on selective medium (PDA with chloramphenicol), and stored on PDA at a 25°C in the incubator, (a) strain of Cladosporium spp., (b) Lasiodiplodia spp., (c) Colletotrichum spp., (d) Fusarium spp. spp. and (e) Aspergillus spp..
Figure 14.
Mean diameter (cm) of fungal decay circles in banana samples inoculated with Cladosporium spp., Lasiodiplodia spp. Colletotrichum spp., Fusarium spp. and Aspergillus spp. for 6 weeks, stored at 13°C and 95% HR (n=20).
Figure 14.
Mean diameter (cm) of fungal decay circles in banana samples inoculated with Cladosporium spp., Lasiodiplodia spp. Colletotrichum spp., Fusarium spp. and Aspergillus spp. for 6 weeks, stored at 13°C and 95% HR (n=20).
Table 1.
Macroscopic characterization of (a) Cladosporium spp., (b) Lasiodiplodia spp., (c) Colletotrichum spp., (d) Fusarium spp. and (e) Aspergillus spp. considering appearance of upper side and lower side.
Table 1.
Macroscopic characterization of (a) Cladosporium spp., (b) Lasiodiplodia spp., (c) Colletotrichum spp., (d) Fusarium spp. and (e) Aspergillus spp. considering appearance of upper side and lower side.
Table 2.
Microscopic characterization of (a) Cladosporium spp., (b) Lasiodiplodia spp., (c) Colletotrichum spp., (d) Fusarium spp. spp. and (e) Aspergillus spp. observed under the microscope.
Table 2.
Microscopic characterization of (a) Cladosporium spp., (b) Lasiodiplodia spp., (c) Colletotrichum spp., (d) Fusarium spp. spp. and (e) Aspergillus spp. observed under the microscope.
Table 3.
Evaluation of antifungal activity in vitro of essential oil against Cladosporium spp., Lasiodiplodia spp., Colletotrichum spp., Fusarium spp. and Aspergillus spp. strain, using oregano, rosemary, clove, thyme, cinnamon and basil essential oils.
Table 3.
Evaluation of antifungal activity in vitro of essential oil against Cladosporium spp., Lasiodiplodia spp., Colletotrichum spp., Fusarium spp. and Aspergillus spp. strain, using oregano, rosemary, clove, thyme, cinnamon and basil essential oils.