June 6, 2013

90-Day Soy-Free Period helps to Control Soy Rust and Insect Pests

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

On June 15th the 90-day soybean free period will once again take effect in most soybean producing states in Brazil. During this 90-day period, no live soybean plants are permitted in the participating states. The original intent of the regulation, which has been in effect since the mid-2000's, was to help slow the spread of soybean rust from one soybean crop to another. The idea is that if soybean plants are eliminated then the rust spores will not carry over from one crop to the next.

Soybean rust (Phakopsora pachyrhiz) was first discovered in Brazil during the 2001/02 growing season and since then it has become the number one disease affecting soybean production in Brazil. The disease, which is native to Asia, was first found in neighboring Paraguay, but it was never determined how it migrated from Asia to South America. It is speculated that it hitched a ride on packaging material in shipments from China, but it was never proven. Regardless of how it arrived, it has caused billions in loses over the intervening years for Brazilian soybean producers in lost production and increased control costs.

Brazilian scientists and farmers have learned how to somewhat control the disease and one of the ways it to prohibit any live soybean plants between crops. During the 90-day prohibition period, no commercial soybean production is permitted and all volunteer soybeans that may have germinated after the harvest was complete must also be eliminated. This includes volunteer soybeans in the fields, along the margins of the fields, along roadways, and around storage units and transportation facilities.

If someone is found to have willfully violated the prohibition or not make a good faith effort to eliminate volunteer soybeans once notified, they may be required to pay hefty fines. Last year in Parana, there were 130 people fined between R$ 50 to R$ 5,000 (US$ 25 to 2,500) for having violated the prohibition. This year the fines have been increased to R$ 220 to R$ 11,950 (US$ 105 to 5,700).

This year, the 90-day soybean free period is also expected to help slow the spread of a new and devastating insect pest. An invasive caterpillar (Helicoverpa armigera), which is commonly known as corn ear worms or cotton boll worms, caused severe damage to the soybean, corn, and cotton crops in the state of Bahia during the 2012/13 growing season. This new species has been discovered in Bahia, Mato Grosso, Parana and eight other Brazilian states.

There are no chemicals currently registered in Brazil to control the insect and scientists are trying their best to contain the problem while the registration process proceeds. Entomologists feel the insect currently has the upper hand since there are no natural enemies, there is plenty of available food, there are no harsh winters to kill off the insect, and it is a prolific reproducer. Scientists say a coordinated effort similar to or greater than what was done to help control rust is urgently needed before the situation gets out of control. Damage from the insect has already been documented on soybeans, corn, cotton, millet, citrus, tomatoes, dry beans, onions, and lettuce.