APPLICATION OF CERTAIN RESISTANCE INDUCERS FOR CONTROLLING FABA BEAN WILT DISEASE UNDER GREENHOUSE AND FIELD CONDITIONS

Abstract

Fusarium oxysporum f.sp. fabae (Schlecht) Snyder &.Hansen (FOF) is a serious pathogen on faba bean causing wilt disease. In greenhouse experiments, the three tested isolates of the pathogen were differed in their virulence on faba bean cultivars (Giza 29, Giza 4 and Misr 1). Isolate (FF1) was the most virulent one. Faba bean cultivars reacted differently to the infection by FOF isolates. While cv. Misr 1 was the most susceptible one, cvs Giza 29 and Giza 4 showed moderate resistance. In vitro testes, the resistance inducers ascorbic acid (AS) and acetic acid (AA) reduced dry weight of the pathogen followed by salicylic acid (SA) and oxalic acid (OA). Effectiveness of the tested resistance inducers in controlling the disease was tested under greenhouse and field conditions. All applied treatments protected faba bean seedlings against FOF in greenhouse. The most effective treatments were AS and AA treatments, however in field experiments, seed treatments by OA, AA, AS and SA reduced the disease incidence. Almost tested treatments significantly increased cellulose content in treated plants except OA treatment compared with untreated plants. The highest reduction in disease incidence was obtained with AS, AA and SA treatments. Seed treatment with AA and AS significantly increased pectin content in treated plants compared with untreated ones. Faba bean seed treatment with 1 % (AS) exhibited the highest content of lignin, while, seed treatment with 0.25 % (AA) exhibited the lowest lignin levels.