The antagonistic activity of two yeast strains (Pichia anomala(E.C. Hansen) Kurtzman, strain K andCandida oleophilaMontrocher,
strain O) against the parasitic complex responsible for banana crown rot was evaluated. The strains were applied at three different concentrations (10
6
,10
7
,10
8
cfu/ml) and their efficacy testedin vivo on three separate fungi (Colletotrichum musae(Berk. & Curt.) Arx,
Fusarium moniliformeSheldon, andCephalosporiumsp.) and on a parasitic complex formed by association of these three fungi. At
the concentrations used C. musaeappeared to be the most pathogenic. The complex showed intermediate aggressiveness between
C. musaeand both other fungi.
Statistically significant antagonistic effects were observed onC. musae,F. moniliforme, and the fungal complex. The highest protection
level (54.4%) was observed with strain O added at 10
8
cfu/ml on crowns previously inoculated with the fungal complex. The level was
lower when the fungi were inoculated separately.
Furthermore, the antagonistic effect was strongly reinforced when strain O at 10
8
cfu/ml was applied 24 h before fungal complex inoculation (59.9%), as compared to its application 15 min (24.3%) or 3 h (27.3%) after fungal complex inoculation. Bananas showed
increased susceptibility to the fungal complex from March to June, and this influenced the level of protection by yeast, which decreased
over the same period. A strict negative correlation (R
2
= 0.83) was highlighted between susceptibility of banana to crown rot and protection provided by yeast