Antimicrobial Evaluation of Asphodelus microcephalus Extracts and Fine Powder of Dried Organs Against Fusarium and Oomycetes Responsible for Apple and Peach Decline Disease

Seedlings root and collar rot is an important disease that causes a reduction in plant production. The goal of this investigation was to evaluate the in vitro and in vivo efficiency of powdered preparation of dried Asphodelus microcephalus of fruits (PPDF), leaves (PPDL), and roots (PPDR) against species of Fusarium and Pythiaceaes associated with this disease in Tunisian nurseries. The in vitro tests of methanolic and aqueous extracts of different Asphodelus organs showed their efficacy in reducing the pathogen mycelium growth. The in vivo assay of powdered preparation of this dried plant revealed that its effect depends on the pathogens, Asphodelus organs, and the period duration between the treatment and inoculation of seedlings. This study showed that this plant has some positive effects, such as disease severity reduction and plant growth stimulation. In fact, for Fusarium solani, the powder of different organs of Asphodelus was used one week before the plantation, and inoculation significantly improved the peach plant’s height. The treatments eight weeks before the inoculation enhanced the root weight of the plants. Meanwhile, the PPDL and PPDR were used eight weeks before the plantation, and inoculation induced the plant disease index. However, the A. microcephalus treatments also have some toxic effects on peach and apple seedlings, such as the improvement of root browning induced by some pathogens.