Plant extracts in the control of the fungus Fusarium oxysporum and its effect on arbuscular mycorrhizal fungi in maize plants

Abstract

With an important role in agroecology, plant extracts have been proposed as an alternative method to pesticides in the control of phytopathogens, especially those of the Fusarium genus, but their effect on beneficial mycorrhiza-forming fungi is questioned. Therefore, the objective of this study was to verify the effect of aqueous plant extracts of Mentha spicata, Tagetes patula, Cymbopogon nardus and Allium sativum, on the mycelial growth of Fusarium oxysporum and on the formation of mycorrhiza for different species of arbuscular mycorrhizal fungi (AMF), under controlled conditions. For the evaluation of the antifungal activity of the extracts in F. oxysporum, aqueous extracts were prepared in concentrations of 0 and 10%, with subsequent incorporation in PDA culture medium. For analysis of the influence on the formation of mycorrhiza, concentrations were tested of 2.5; 5.0; 7.5 and 10.0% of the Allium extract, with the highest previous antifungal activity. For all concentrations there was a negative effect on the formation of mycorrhiza, in corn inoculated with Gigaspora rosea or Rhizophagus clarus, mainly for the first AMF specie.