Chitosan gel formulation, drying profile and influence of its application on gas exchange

Abstract

Citriculture is an important economic activity for Brazil, which is the largest exporter of sweet orange juice in the world. Historically, the country has faced difficulties in the sector due to losses related to pests and diseases that affect crops, especially citrus canker. This bacterial disease affects the entire aerial part of the plants and, in severe cases, causes defoliation and premature fruit drop. In addition to the loss caused by the disease, there are international restrictions on the marketing of oranges from countries where the canker is present, in an attempt to prevent the spread of the disease. The disease control is carried out by integrated management techniques that include the recurrent application of metallic copper. This method is effective in reducing the spread of the cancer, but it has no curative effect. In addition, copper is a heavy metal that can have several undesirable effects on humans and the environment. In an attempt to minimize or even replace the massive use of copper in crops, researchers have sought alternatives such as the use of natural oils capable of inhibiting the growth of phytopathogens. Although these products already exist and are effective in disease control, they have little adherence to the substrate and are easily degraded by weathering. For an efficient application of these compounds, it is necessary to develop carriers capable of attaching to the substrate and protecting the compounds. From this perspective, this project proposes to evaluate the properties of chitosan gels and their interference with the physiology of orange trees in order to use this polymer as a carrier of compounds in the form of dense, porous (network) biofilms and as microparticles. This project will contribute to the specific objectives of the Fapesp Thematic Project (process 2021/10839-4), evaluating the biogel formulation and its effect on orange tree application.