Revista Industrial y Agrícola de Tucumán ()
Efficacy of fungicides used in vitro to control Fusarium oxysporum and F. proliferatum, causal agents of oregano wilting in Argentina
Abstract
In Argentina, the oregano herb (Origanum vulgare L.) is a product for both domestic consumption and exports. Córdoba province ranks second nationally for its area planted with this aromatic, but certain agronomic management and plant health problems have to be tackled. Fusarium oxysporum Schltdl. and F. proliferatum (Matsushima) Nirenberg are the causal agents of wilting and plant death in the crop. The objective of this experience was to evaluate in vitro the efficacy of fungicides with different modes of action and unrelated chemical groups in controlling both local Fusarium spp. isolates. Systemic fungicides carbendazim, thiabendazole, thiophanate-methyl and tebuconazole, as well as the contact fungicide mancozeb, were assessed at three different doses: the recommended one, half a dose and double dose. The efficacy of these fungicides in controlling fungi was determined using the poisoned food technique and assessed as the percent inhibition of mycelial growth (PIMG) as accomplished with each fungicide. Assays were performed separately for each species of the pathogen and a nested randomized complete block design was utilized, with the dose factor nested within the fungicide factor. Data were analyzed using Anava, and differences between treatment means with Fisher LSD (p<0.05). F. oxysporum and F. proliferatum were susceptible to all fungicides, showing significant differences (p <0.0001) in PIMG at the different doses tested. In all cases, higher doses produced the highest PIMG, whereas the lowest value was produced by lower doses. For both pathogens, the systemic fungicides tebuconazole and carbendazim were the most effective in inhibiting mycelial growth. These were followed in efficacy by thiabendazole and thiophanate-methyl, and finally by the contact fungicide mancozeb.
