Biocontrol of Penicillium digitatum on Postharvest Citrus Fruits by Pseudomonas fluorescens

Table 1

The effect of P. fluorescens on the mycelial growth of P. digitatum.

Treatments	Plate central mixed culture		Plate confrontation culture
	Mycelium growth (cm)	Inhibition rate (%)	Mycelium growth (cm)	Inhibition rate (%)
SDW	6.20 ± 0.17a	0.00 ± 0.00c	6.28 ± 0.07a	0.00 ± 0.00c
Autoclaved cultures	4.88 ± 0.08b	21.23 ± 1.61b	5.18 ± 0.09b	17.52 ± 1.41b
Culture filtrate	4.62 ± 0.11b	25.42 ± 2.26b	5.06 ± 0.12b	19.51 ± 1.90b
Bacterial suspension	0.00 ± 0.00c	100.00 ± 0.00c	3.70 ± 0.08c	41.04 ± 1.30a
Bacterial fluid	0.00 ± 0.00c	100.00 ± 0.00c	3.67 ± 0.0.13c	41.56 ± 2.13a

SDW, sterile distilled water, was prepared by autoclaving deionized water at 121°C for 20 min. Autoclaved cultures were prepared by autoclaving 1 × 10⁸ CFU/ml bacterial fluid at 121°C for 20 min. Culture filtrate was prepared by using a 0.22 μm polycarbonate membrane filter to filtrate the supernatants. Bacterial suspension (1 × 10⁸ CFU/mL) was prepared by using SDW to wash the bacterial precipitation twice to remove the residual culture medium. Bacterial fluid (1 × 10⁸ CFU/mL) was prepared by diluting the culture (about 1.5 × 10¹⁰ CFU/mL) with culture filtrates. Values in a column followed by a different letter are significantly different according to Duncan’s multiple range test at level.