May 29, 2006

Mexican soy hit by soy rust
 

More than 20 soybean seed growers near Tampico, Mexico, discovered Asian soybean rust in their fields this spring, with nearly 650 acres were affected. The rust is cause for concern as the area is just 200 miles from Texas, meaning that it could spread to the US, given the right conditions. 

The problem was discovered in April and farmers were caught by surprise, said Marty Wiglesworth, Syngenta's technical brand manager for fungicides. The disease led on to defoliation and potential yield losses.

However, the seed plants were harvested in the end of April and early part of May so the infected plants have been destroyed.

Despite the proximity, experts say the threat to US growers is minimal.

The planting gap between the south and north should reduce US worries, said X B  Yang, an Iowa State University plant pathologist.

Mexican soybean growers near the Texas border would begin planting their beans in late May. The month-long gap between the harvest in the Tampico area -- where the infected fields were found -- and planting in northern Mexico reduces the possibility of the disease propagating.

However, Wiglesworth said the impact on the US crop now is hard to predict and depends on whether there are nearby patches of alternative plants such as kudzu for the disease to live on until the newly planted Mexican crop matures. The aridity of the area may also hinder the disease's ability to spread.

Experts believe the risk of the rust spreading to East Texas is low as the wind from Mexico is not favourable toward the US, and if spores were to arrive, it would be late in the season.

No effective soybean rust fungicides are allocated in Mexico, but agrichemical companies, including Syngenta, are pursuing emergency exemptions for rust specific fungicides.