Pathogenicity and biological control of bayoud disease by trichoderma longibrachiatum and artemisia herba-alba essential oil

Abstract

All the Fusarium oxysporum f. sp. albedinis (Foa) isolated from rachis were pathogenic to the date palm seedlings cultivar Deglet Nour, while Fusarium sp. isolated from soil (E1, E2, and E3) did not show any aggressiveness against these seedlings. In vitro antagonistic effect of Trichoderma longibrachiatum against three isolates of Foa tested by direct confrontation or remote confrontation on Potato Sucrose Agar (PSA) medium, revealed that the latest has inhibited mycelial growth of the pathogen by more than 60%, compared to the control and this after an incubation period of six days at 27 ± 2°C. Mycelial growth of T. longibrachiatum occupied the whole Petri dish after three days of incubation while the three isolates of Foa (T15D, M15A1, and O15T) occupied only 17%, 11%, and 20%, of the surface respectively. Biological control with essential oil of Artemisia herba-alba yielded important results with a minimum inhibitory concentration (MIC) ranging from 2.5 to 5 μl/ml and a minimum fungicidal concentration (MFC) of 80 μl/ml.