<i>Nigrospora</i> sp. in post-harvest papayas: efficacy of essential oils in antifungal inhibition

Larissa G. R. Duarte; Isadora C. Pedrino; Ygor G. P. Osti; Conny W. T. Fukuyama; Pedro H. B. Nogueira; Maria Eduarda de A. Astolfo; Maria Eduarda da M. Martins; Stanislau Bogusz Junior; Marcos D. Ferreira; Larissa G. R. Duarte; Isadora C. Pedrino; Ygor G. P. Osti; Conny W. T. Fukuyama; Pedro H. B. Nogueira; Maria Eduarda de A. Astolfo; Maria Eduarda da M. Martins; Stanislau Bogusz Junior; Marcos D. Ferreira

doi:10.48130/tihort-0025-0002

Figures (3) Tables (4)

Figure 1.
Images obtained by scanning electron microscopy (SEM) of the morphology of the fungus Nigrospora sp. under the action of the essential oils Syzygium aromaticum and Origanum vulgare at (a)−(c) magnification 2,000× and scale bar 10 μm, and (d)−(f) magnification 5,000× and scale bar 5 μm. (a), (d) Control, (b), (e) CEO, (c), (f) OEO.
Figure 2.
Weight loss of papaya during storage at 25 °C and 70% RH treated without essential oil (control), with Syzygium aromaticum essential oil (CEO) and with Origanum vulgare essential oil (OEO). For each storage period, different letters indicate significant differences among treatments (p < 0.05).
Figure 3.
Area under the disease progress curve (AUDPC) for lesion diameter values (mm) in papaya fruits treated (a) with Syzygium aromaticum essential oil (CEO), and (b) with essential oil of Origanum vulgare (OEO) in a preventive (P) and curative (C) manner. Different letters indicate significant differences among treatments (p < 0.05).

Compound	Syzigium aromaticum (% area)	Origanum vulgare (% area)
Eugenol	90.75	−
β-caryophyllene	7.81	−
β-myrcene	−	1.45
α-terpinene	−	1.22
p-cymene	−	8.69
γ-terpinene	−	6.15
Thymol	−	8.13
Carvacrol	−	67.89
Caryophyllene	−	1.86
Total	98.56	95.39

Table 1.

Major compounds of Syzygium aromaticum and Origanum vulgare essential oils.

Concentration (μL·L⁻¹)	Syzygium aromaticum	Origanum vulgare
0	0.00 ± 0.00	0.00 ± 0.00
62.5	59.48 ± 2.83	35.11 ± 4.82
125	66.69 ± 0.28	82.83 ± 2.37
250	100.00 ± 0.00	100.00 ± 0.00
500	100.00 ± 0.00	100.00 ± 0.00
750	100.00 ± 0.00	100.00 ± 0.00
1,000	100.00 ± 0.00	100.00 ± 0.00
MIC	125 < MIC ≤ 250	125 < MIC ≤ 250

Table 2.

Percentage inhibition of mycelial growth of Nigrospora sp. and Minimum Inhibitory Concentration (MIC) of Syzygium aromaticum and Origanum vulgare essential oils at different concentrations (μL·L⁻¹).

Storage time (d)	Length (cm)				Diameter (cm)
Storage time (d)	0	2	5	8	0	2	5	8
Control	17.26 ± 0.56^a	16.54 ± 0.95^a	15.75 ± 0.63^b	15.09 ± 0.83^b	25.25 ± 0.44^a	24.82 ± 0.68^a	23.97 ± 0.57^b	23.05 ± 0.58^b
CEO	17.28 ± 0.98^a	17.20 ± 0.82^a	17.15 ± 0.62^a	17.11 ± 0.88^a	25.19 ± 0.52^a	25.15 ± 0.78^a	25.11 ± 0.65^a	25.09 ± 0.80^a
OEO	17.25 ± 0.71^a	17.21 ± 0.97^a	17.18 ± 0.88^a	17.13 ± 0.63^a	25.22 ± 0.65^a	25.16 ± 0.54^a	25.10 ± 0.71^a	25.07 ± 0.75^a
Means followed by different letters on the same column indicate significant differences among treatments (p < 0.05).

Table 3.

Length and diameter of papaya fruits over storage time (8 d) treated without essential oil (control), with Syzygium aromaticum essential oil (CEO), and with Origanum vulgare essential oil (OEO).

Time (d)	Treatments	L*	C*	(hº)
0	Control	64.10 ± 5.77^a	57.56 ± 2.92^b	101.05 ± 1.13^a
	CEO	66.01 ± 9.35^a	62.90 ± 7.37^a	93.22 ± 7.05^b
	OEO	65.50 ± 7.11^a	49.67 ± 7.18^c	101.67 ± 3.29^a
2	Control	63.53 ± 6.16^a	54.21 ± 6.93^b	87.47 ± 4.91^b
	CEO	65.59 ± 7.38^a	60.92 ± 11.79^a	84.45 ± 10.67^b
	OEO	64.79 ± 7.99^a	47.23 ± 10.65^c	94.36 ± 8.36^a
5	Control	61.75 ± 6.80^a	53.96 ± 6.58^b	74.71 ± 5.64^a
	CEO	65.35 ± 5.78^a	60.54 ± 8.47^a	73.72 ± 8.55^a
	OEO	64.41 ± 10.88^a	45.97 ± 9.79^c	77.73 ± 8.53^a
8	Control	54.98 ± 7.90^a	52.81 ± 15.07^a	70.54 ± 3.78^b
	CEO	60.14 ± 8.28^a	59.29 ± 13.55^a	68.81 ± 4.22^b
	OEO	61.70 ± 7.78^a	40.94 ± 9.21^b	77.27 ± 5.08^a
Means followed by different letters on the same column indicate significant differences among treatments (p < 0.05). The values presented in this table are the means ± standard deviations.

Table 4.

Color parameters L*, C*, and h° of papayas stored for 8 d at 25 °C and 70% RH treated without essential oil (control), with Syzygium aromaticum essential oil (CEO), and with Origanum vulgare essential oil (OEO).