Aerobiology of Peronospora manshurica, causal agent of soybean downy mildew, in Passo Fundo, RS

ABSTRACT

In a study conducted in the field during the 2020/211 soybean season, the weekly fluctuation of Peronospora manshurica conidia present in the air was quantified. To trap the spores, a Smar Agri spore collector was installed on December 7, the day of soybean sowing, including weekly exposure of microscopic slides, which extended until April 12, 2021. The first spores were collected on January 25, reaching zero on March 22, which accounted for1,845 total spores collected. It was concluded that the spores collected 40 days after sowing originated within the monitored area and not from an external source. Finally, these pioneering data on P. manshurica aerobiology are not intended to be used as a criterion to indicate the moment to start applying fungicides to soybeans

Keywords
spore collector; anemophilous spore dissemination; inoculum source; Glycine max