Characterization and pathogenicity of fusarium proliferatum on date palms in Algeria.

Abstract

During a survey conducted from 2013-2014, in order to determine the fungal agents of wilt and dieback of date palms (Phoenix dactylifera L.) from Ghardaia province in Southern Algeria, two Fusarium species; Fusarium oxysporum, Fusarium proliferatum and Thielaviopsis sp were identified based on their cultural and morphological characteristics. Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg was isolated and identified, and Koch's postulates were completed. Morphological identification was based on morphological characteristics on PDA and SNA culture media, and it was confirmed molecularly using ribosomal DNA sequence. Data comparison of the sequence (KR 856363) at GenBank revealed 100 % similarity to this fungal species. A phytopathogenicity test was carried out with 3 months old plants, and they were inoculated by dipping the roots into a fungal conidial suspension and also compared with Fusarium oxysporum f. sp. albedinis (Kill. & Maire) Malencon, known causal agent of date palm Fusarium wilt (Bayoud disease). After 90 days, disease incidence was eventually 76.66 % and 80 % for F. proliferatum and F. oxysporum, respectively, and the calculus of the index shows that this fungus would be a very serious threat to date palm. Microscopic observation of the roots provided confirmatory evidence that F proliferatum is causing a vascular disease on date palm.