Fungicidal activity of slow-release formulations of tebuconazole and epoxiconazole to control root rot pathogens of cereal crops

Abstract

This study attempts to develop a new way to deliver fungicides that will reduce the concentration of chemicals in the soil, while maintaining the effectiveness, provide a prolonged effect of the fungicide and reduce the number of treatments during the growing season. For this purpose, the systemic fungicides tebuconazole and epoxiconazole were embedded in biodegradable matrix consisting of homopolymer poly(3-hydroxybutyrate) and wood flour. Dry components were mixed and formed as granules, which were introduced into the soil with cereal seeds - spring wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.). The control groups included intact plants and plants treated with free forms of fungicides. The response of plants to the use of slow-release and free forms of fungicides was assessed by the morphometry of the aerial part and production of carbonylated proteins, malondialdehyde, and proline in plant root cells. The fungicidal activity of the preparations was evaluated by the effectiveness of plant pathogenic fungi suppressing in the soil and on plant roots during the growing season. The results showed that the effect of embedded and free fungicides on redox homeostasis in wheat and barley roots varied depending on the plant growth stage and differed significantly between plant species. The embedded fungicides were more effective in reducing root infection than the free analogues. The use of fungicides in granules led to a decrease in the incidence of root rot in both cereals by 1.5–1.9 times and an increase in the dry mass of plants by 20–28 % in wheat and by 15–18 % in barley. Fungicidal preparations embedded in a degradable base provide long-term protection of plants from soil pathogens and the root diseases control.