Soybean rust alert system activated in the Brazilian state of Parana

Author: Michael Cordonnier/Soybean & Corn Advisor, Inc.

Soybean planting has been delayed in the southern Brazilian state of Parana due to dry weather, but state officials are already preparing to try to help control soybean rust, which is the most important disease of soybeans. Soybean rust is caused by the fungus Phakopsora pachyrhizis and if left unchecked, it can cause losses of up to 90%.

On October 15th, the Parana Institute of Rural Development (IDR) partnered with Emater to officially start their Rust Alert program for the 2020/21 growing season. This is the fourth year for the Rust Alert system that monitors the presence and spread of soybean rust spores to help farmers better manage and control the disease.

The Rust Alert program will install 250 collection devises in strategic locations across the state to monitor the presence of soybean rust spores. The collection devises are simply a piece of PCV pipe that can rotate according to the wind direction. Inside the pipe is a piece of special adhesive tape that can trap rust spores that pass through the pipe.

The tapes are collected periodically and analyzed in the laboratory for the presence of spores. If spores are detected, the information is announced on local radio stations and through social media. Farmers can also download an app that will alert them for the presence of rust spores in their area.

One goal of the program is to help farmers better manage their rust control measures. Scientists recommend that fungicide applications only be applied when three factors are present - the soybeans are in their reproductive phase, rust spores are present in the region, and the weather is favorable for disease development. Farmers are advised to consult with local technicians before they decide to start fungicide applications.

In the past, farmers may have applied fungicides based on the calendar date without knowing if an application was necessary. Farmers who used the Rust Alert system during the 2019/20 growing season reduced their fungicide applications by 30% and they lowered their cost of production by 1.8 sacks per hectare (1.6 bu/ac). In fact, the program director indicated that 11% of the farmers who used the Rust alert system in 2019/20 did not apply any fungicides to their soybeans.

The Rust Alert system this growing season will also include weather information for farmers such as: weather forecasts, rainfall amounts, soil moisture, temperatures, climate maps, and frost alerts of coffee producers.

There have not yet been any confirmed cases of soybean rust in Parana, but the state traditionally has the highest number of rust cases of any state in Brazil.