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October 7, 2013

Soy Farmers in Brazil Warned of White Mold and Corn Ear Worm

Soybean farmers in Brazil have been warned to be alert for two new potential problems in the soybean fields - white mold and the corn ear worms, both of which are relative new to soybean producers in Brazil.

White mold has been a problem for U.S. soybean producers for many years, but it is relatively new in Brazil. The soil borne fungus is more common in areas where nighttime temperatures are cooler, which in Brazil means areas of higher elevation or areas that exceed 450 meters in elevation. The fungus has been found in the soils of the northern Brazilian state of Maranhao all the way south to the soils of Rio Grande do Sul, but it is of particular concern in the Campos Gerais region of eastern Parana where cool nights due to the higher elevation are common.

The mold attacks the lower part of the plant during flowering in December and January, which makes it difficult to control with fungicides. In order for the fungicide to control the disease, the spray must penetrate the canopy all the way to the bottom of the plant which is difficult to do. The best way to control the disease is with crop rotations and planting soybean varieties more resistant to the disease. If left untreated, the disease can cause losses up to 70% in the worst case scenarios.

Another new pest that farmers must be on the lookout for is the leaf-eating worm of the Helicoverpa species or more commonly known as the corn ear worm. Scientists in Mato Grosso are very concerned because they found a high infestation of the worm in all five areas of the state where they looked for it on volunteer soybean plants.

This pest was first identified last growing season in western Bahia where it caused significant damage to the soybean, corn and cotton crops in the state. The pest has since been identified all across central Brazil and scientists and government officials have been scrambling to register the proper chemical controls for the pest. As of yet, it is unknown how the pest suddenly appeared in western Bahia last growing season.

When it first appeared in Bahia, farmers did not know the proper chemical control or the timing of the applications. Scientists now feel they have a better understanding of the proper control methods, but this new pest has the potential to cause significant damage. At the very least, it is going to cause farmers to spend more money on insecticide applications.