South America Calling

Southern Brazil is seeing a surge in cases of Asian rust fungus among soybean crops as a result of the heavy rain experienced over the last couple of months.

Some 167 cases of the aggressive fungus have been identified since the season started in September, up from 95 at the same stage last year, according to the Anti-Rust Consortium, a monitoring group set up by government researchers. The southern state of Parana has registered the most cases at 82, up from 24 last year. Next comes the southernmost state of Rio Grande do Sul with 49 cases, up from 21 at the same stage last year.

Rust represents perhaps the biggest single threat to Brazilian soybeans. It causes lesions on the leaves of soybean plants, which impede the formation of the bean and can result in massive yield losses. If left unchecked, the fungus can kill the plant.

Cases proliferate at the end of the season, when beans are maturing, and so high mid-season levels are a worrying sign.

However, farmers are spraying regularly and the situation remains under control, according to Marcelo Garrido, agronomist at the Parana State Farm Department (DERAL).

The heavy rains in the south have been caused by elevated activity of the El Nino weather phenomenon, which is expected to prevail until March. If that happens, southern growers will have to spend substantial sums on fungicides.

On the plus side, the dry weather in Mato Grosso, the center-west state responsible for a third of output, means there have only five reported cases in the state as we near harvest season.

(CZ)

© Copyright 2015 DTN/The Progressive Farmer. All rights reserved.