Table 3.
Minimum inhibitory concentrations and minimum bactericidal concentrations of essential oils of Tagetes minuta on three plant pathogenic bacteria.
| Tube/plate number | EOs concentration (mg/mL) ∗ 102 | Growth of bacteria in MHB tubes | Growth of bacteria in MHA plates | ||||
|---|---|---|---|---|---|---|---|
| XAP | XAM | PSP | XAP | XAM | PSP | ||
| #1 | Crude EOs | − | − | − | − | − | − |
| #2 | 3.8 | − | − | − | − | − | − |
| #3 | 1.9 | − | − | − | − | − | − |
| #4 | 0.95 | − | − | − | − | + | − |
| #5 | 0.48 | − | − | − | + | + | + |
| #6 | 0.24 | − | + | − | + | + | + |
| #7 | 0.12 | + | + | + | + | + | + |
| #8 | 0.06 | + | + | + | + | + | + |
| #9 | 0.03 | + | + | + | + | + | + |
| #10 | 0.015 | + | + | + | + | + | + |
| #11 | −ve control | + | + | + | + | + | + |
| #13 | +ve control | − | − | − | − | − | − |
[+]: growth; [−]: no growth of the bacteria; and XAP: X. axonopodis pv. phaseoli, XAM: X. axonopodis pv. manihotis, and PSP: P. savastanoi pv. Phaseolicola.
MHB: Muller-Hinton broth; MHA: Muller-Hinton Agar; tube 1: bacterial inoculum and undiluted crude essential oils; tubes 2 to 10: MHB, bacterial inocula, and essential oils of different concentrations; tube 11: bacterial inoculum and MHB (−ve control); and tube 13: bacterial inoculum, MHB, and the standard bactericide (+ve control).