January 11, 2007

Excess rains in Brazil likely cause of soy leaf damage

Crop scientists from Brazil's top soy research institute, Embrapa Soja, said Wednesday that excessive rainfall is the likely cause for lesions on soy leaves in nine farm towns in southern Brazil.

"We don't know for sure what is causing these lesions, but they have been detected in Brazil, Argentina and Bolivia since the 1990s," said Claudine Seixas, a plant disease specialist at Embrapa.

"We've seen this before, but nothing of this magnitude," she said, adding that the leaf damage has never led to crop losses in the past.

Seven towns in Parana state, and one town in Santa Catarina and Mato Grosso do Sul reported hundreds of tiny brown dots taking over the green leaves of soybean plants, now in their late stages of development. In some cases, the lesions are brown with a clear, white centre and are well distributed throughout the leave.

Embrapa said it is not a disease.

In Parana, January rainfall is currently 221.6 millimetres compared with 111 millimetres throughout all of January 2006, according to the Agronomy Institute of Parana, the research arm of the state's Secretary of Agriculture.

The only known study on the lesions have been published by Argentine scientist, Daniel Ploper, which found leaf damage occurred mostly during years of frequent, heavy rainfall, Embrapa said in a press statement.

Brazil is the world's no. 2 soy producer and exporter behind the US and is expected to harvest close to 54.7 million tonnes, according to the National Commodities Supply Corp.