Controle biológico in vitro de mofo branco (Sclerotinia sclerotiorum) na cultura da soja.

Abstract

Soybean cultivation is one of the most important for the Brazilian economy. However, diseases such as white mold, caused by the fungus Sclerotinia sclerotiorum, have represented serious obstacles to crop productivity. This pathogen has a wide range of hosts, a high capacity for dissemination, and resistance structures that hinder its control, making its management a constant challenge. Traditionally, disease control has been carried out using chemical fungicides. However, the ineffectiveness of these products against pathogen resistance and the associated environmental impacts have encouraged the search for more sustainable alternatives. Among them, biological control, with Trichoderma spp., has stood out due to its action through mycoparasitism, antibiosis, and competition for nutrients, in addition to allowing different forms of application. To evaluate and compare the efficacy of different concentrations of the biological products Trichodermil Super SC® (Trichoderma harzianum) and Quality WG® (Trichoderma asperellum) in the in vitro control of white mold (Sclerotinia sclerotiorum), in order to determine the most efficient product and dose for inhibiting the pathogen in which sclerotinia has already developed. The experiment was conducted in a completely randomized design (CRD) with 30 Petri dishes (10 treatments x 3 replicates). After the development of the pathogen, fractional doses (1/4, 2/4), the recommended dose, and double doses of the products were applied, in addition to a combined treatment. Efficacy was monitored for 14 days, measuring the growth diameter of Trichoderma and the coverage area.The commercial product with the best performance in the experiment was Trichodermil Super SC®, with the treatment at twice the recommended dose showing the best results. In contrast, treatments with the Quality WG® product showed the worst results, with the lowest growth observed at the recommended dose of the commercial product. The treatment that combined the two products at the recommended doses obtained median results. CONCLUSION: These findings reinforce the potential of biological control in the management of white mold, highlighting the superiority of T. harzianum under the tested conditions.