In vitro evaluation of compost extracts efficiency as biocontrol agent of date palm Fusarium wilt

Bayoud, vascular wilt of date palm caused by Fusarium oxysporum f. sp. albedinis (Foa), is widely distributed in all date palm growing regions of Morocco. It is the most serious disease of the date palm. Compost is recognized for their ability to improve soil characteristics and to protect the crops against biotic and abiotic stress. In this experiment, in vitro effects of different concentrations of sterilized and unsterilized compost extract on the growth of F. oxysporum f. sp. albedinis were evaluated. All concentration of unsterilized compost extract decreased radial growth of Foa. In fact, fungal radial growth inhibition ranged from 20 to 97%.  Higher antifungal activity was noted in 30 and 40% concentration (more than 93%). Nevertheless, sterile compost extract inhibited mycelia growth only for the 40% concentration with 18% fungal growth inhibition, while lower concentrations were not effective. Key words: Date palm, Fusarium oxysporum f. sp. albedinis, compost extract, mycelium growth, inhibition rate.