SURVIVAL MECHANISMS OF Fusarium oxysporum f. sp. passiflorae ARE AFFECTED BY APPLICATION OF CABBAGE AND CASSAVA DEBRIS

MECANISMOS DE SOBREVIVÊNCIA DE Fusarium oxysporum f. sp. passiflorae SÃO AFETADOS POR APLICAÇÃO DE DEBRIS DE REPOLHO E MANDIOCA

ABSTRACT

Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. passiflorae (Fop) is the main fungal disease in passion fruit crops. Chlamydospores, which are structures of resistance produced by Fop, allow the fungus survival in the soil for several years and have saprophytic activity. Biofumigation with incorporation of cabbage and bitter cassava has been a viable alternative, among management methods, for the control of soil pathogens. The objective of this work was to evaluate the effect of different plant debris (plant residues) on survival of Fop under laboratory conditions. In vitro tests were carried out with incorporation of leaves of yellow passion fruit, cabbage, bitter cassava, and sweet cassava plants into substrates infested with different Fop isolates. Mycelial growth and chlamydospore production and germination were evaluated. The incorporation of cabbage and bitter cassava debris had a fungistatic effect on Fop, with decreases in mycelial growth and chlamydospore production. The incorporation of cabbage into the substrate totally inhibited the chlamydospore germination in 78% of the evaluated isolates and decreased the germination percentage in the others.

Keywords:
Passion fruit plant; Chlamydospores; Plant materials; Saprophytism