December 6, 2010

Soybean Rust Off to a Slow Start in Brazil

The number one disease affecting soybean production in Brazil is soybean rust, but thus far this growing season, only a few cases of rust have been detected. Soybean rust, which is a fungal disease, was first introduced into Brazil during the 2000/01 growing season and it has cost Brazilian farmers approximately US$ 2 billion per year in lost production and chemical costs.

According to Embrapa, the Brazilian research service, only five cases of rust have been reported thus far compared to 50 cases last year at this time. During the 2009/10 growing season, eventually more than two thousand cases of the disease were reported.

Eventually farmers in Brazil will have to start applying fungicides to control the disease and this year the cost of those chemicals are slightly less than they were during the 2009/10 growing season. Embrapa estimates that one tractor application of fungicides to control rust in the state of Mato Grosso do Sul will cost an average of R$ 37.80 per hectare or about US$ 8.80 per acre. During the 2009/10 growing season, that same application cost R$ 43.80 per hectare or about US$ 10.20 per acre.

The fungicides used to control the disease are contact fungicides, which mean they need to be reapplied throughout the growing season. Generally, a new application is required every 25 to 35 days depending on the frequency of rainfall. During wetter than normal periods, the interval between applications is reduced and during dryer than normal periods, the interval can be extended longer than normal. Nationwide, approximately 1.8 to 2.0 applications of fungicides have been needed in recent years to adequately control the disease.

Each year, Brazilian scientists and farmers learn how to better control the disease and Embrapa researchers have developed soybean varieties that are semi-tolerant to the disease. With a few years, Embrapa anticipates that truly resistant soybean varieties will be available for Brazilian producers.