January 23, 2012

Wet Weather in Brazil Slows Harvest, Increases Disease Pressure

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

The persistent wet weather in central Mato Grosso is not only slowing the initial soybean harvest, it is also causing some concerns about the spread of soybean rust. The Mato Grosso Institute of Agricultural Economics (Imea) estimated that as of last Thursday 2.7% of the state's soybean crop had been harvested and that 5% was mature and waiting to be harvested. Imea does not think that the yields have been compromised as yet, but there are reports of poor seed quality due to the wet weather. The poor seed quality is probably being cause by a fungus called Pod and Stem Blight that invades the pods and results in small and shriveled seeds that are acidic and lighter in weight than normal seed.

Embrapa has reported that 41 cases of rust have been confirmed in the state and that number is expected to increase in the near future. While 41 cases does not seem like a large number of cases for a state as large as Mato Grosso (it's six times bigger than the state of Illinois), it is the most number of cases in recent years.

Imea estimates that rust control will cost producers in Sorriso, which is located in central Mato Grosso, R$ 35 per hectare. That cost is based on two fungicide applications. The total cost of production for soybeans grown in Sorriso is estimated by Imea to be R$ 1,655 per hectare (US$ 379 per acre) with operational costs estimated to be R$ 1,018 per hectare (US$ 232 per hectare).

Each fungicide application used for rust control costs approximately one half-sack per hectare (a little less than one-half bushel per acre) or 2% of the total production cost. Agronomist recommend that all producers put on two fungicide applications if soybean rust is present at a low level or not even present at all. If the disease is present in higher concentrations, a producer may have to apply as many as four applications for an increase cost of R$ 70 per hectare (US$ 16 per acre increase). The fungicide is generally applied at the rate of one-half liter per hectare and each liter costs an average of R$ 70.

The farmers in the municipality of Sorriso planted 614,000 hectares of soybeans and 80% of the farmers have reported the presence of soybean rust in their fields. If rust is not adequately controlled, it can easily result in yields being lowered by at least 5 sacks per hectare or 4 bu/ac. No yield losses due to rust have been reported at this point, but if heavy rains continue to fall in Mato Grosso, rust and other fungal diseases such as white mold could become a bigger concern for producers.

The Rural Society of Sorriso is estimating that the average soybean yield in the municipality is expected to be 60 sacks per hectare (3,699 kg/ha or 52 bu/ac).