TABLE 1.

Enhancement of fungicide efficacy by the membrane efflux transport inhibitor 2-(4-ethoxy-phenyl)-chromen-4-one

Fungicide appliedaStrain adaptationbInhibitorcGrowth rate (μm/24 h)d
None (control)Nonadapted540 ± 23
+500 ± 20
Epoxiconazole160 ± 8.2
+120 ± 5.8
Azoxystrobine440 ± 18
+320 ± 16
Kresoxim-methylEpoxiconazolee210 ± 12
+67 ± 4.0
Azoxystrobine130 ± 7.3
+110 ± 9.4
AzoxystrobinEpoxiconazolee190 ± 12
+29 ± 2.6
Azoxystrobine350 ± 15
+26 ± 2.1
PicoxystrobinEpoxiconazolee190 ± 12
+40 ± 5.3
Azoxystrobine170 ± 12
+62 ± 5.8
EpoxyconazoleEpoxiconazolee160 ± 6.6
+50 ± 2.9
Azoxystrobine310 ± 13
+200 ± 12
  • a The concentration of each fungicide was 2.5 mg · liter−1.

  • b Isolates were adapted to 1 mg · liter−1 epoxyconazole or azoxystrobin.

  • c The inhibitor concentration was 2 mg · liter−1.

  • d Mean growth rates of nonadapted and adapted isolates of P. tritici-repentis were measured on biomalt agar in the presence or absence of fungicides and/or inhibitor 24 h after inoculation. The results are based on three replicate experiments, and the values are means ± standard errors.

  • e There were statistically different rates (P ≤ 0.05) of hyphal growth in the presence and in the absence of the inhibitor for each strain and fungicide tested under these conditions.