Correlação de doenças na pré e pós-colheita da soja

Abstract

Soy plays an important role in the Brazilian economy, with significant gains, in recent years, in relation to the quantity of product harvested. Greater gains with the crop are limited by the occurrence of diseases, which can cause damage to the harvested seeds, however, they can be managed with the use of fungicides. Therefore, the objective of the work was to verify if there is a correlation in diseases of pre and post harvest of soybeans through the use or not of fungicides in plants, in trials conducted in the municipalities of Cerro Largo / RS and Roque Gonzales / RS. To this end, two experiments were carried out in two different municipalities: Roque Gonzales and Cerro Largo, both located in the northwest region of the state of Rio Grande do Sul in the 2019/2020 agricultural year. In both experiments, 40 trifolios were marked for condition with use of fungicide and 40 trifoliate where no fungicides were used from sowing to harvest, an area of 6m² was used, where the plants were marked at random. Seven evaluations of disease incidence and severity were carried out, with intervals of seven days, from the vegetative stage V9 (ninth node in the main stem, starting with the leaf node). Upon reaching the point of harvest, the pods of each plant were collected, threshed and individually evaluated for vigor, germination, normal seedlings, abnormal and non-germinated seeds as well as for the height and dry mass of the aerial part and length and mass dryness of the roots, a sanity test was also carried out to identify pathogens present in the seeds. As a result, in the plant evaluations the presence of rust and powdery mildew was not detected, in addition, the incidence and severity of mildew and leaf spots were low in both municipalities where the experiment was carried out. It was observed that the use of fungicides in the plants provided beneficial effects on the variables of physiological quality of the seeds harvested in both places, however, the pathogens detected in the aerial part of the plants did not develop in the harvested seeds.