Soybean producers all across Brazil have been alerted to the possibility that the leaf-eating worm from the Helicoverpa species (Helicoverpa armigera) could start to invade their soybean fields shortly after the crop emerges. The worm more commonly known as the corn earworm or cotton bollworm, has a veracious appetite and can subsist on up to 180 different species of plants including soybeans, corn, and cotton.
The pest was first identified in western Bahia earlier in 2013 and caused an estimated loss of R$ 2 billion in the region. Since the pest had never been previously identified in Brazil, there were no appropriate chemicals registered in Brazil to control the worm. By the time farmers and scientists identified the insect, extensive damage had already occurred to the crops in western Bahia. Since then, the insect has been found in virtually every soybean growing region of central Brazil.
The caterpillar has no natural predators in Brazil and scientists and agricultural organizations are so concerned about this new pest that they convinced the Brazilian Congress to pass emergency legislation authorizing the importation and use of the appropriate insecticides to be used all across the country. The insecticides are already registered in 90 countries with good results in controlling the pest. The legislation (MP 619) passed both houses of Congress and is waiting the signature of President Rousseff.
Technicians in Mato Grosso found large quantities of the worms on virtually every property they visited in recent days. The worms were found on volunteer soybeans, corn, and numerous weed species. Scientists have advised farmers in the state to closely monitor their soybean fields as soon as the crop emerges and be prepared to spray immediately. State agricultural officials and commodity organizations will send out teams of technicians as early as this week to monitor the presence of the insect and advise farmers on the proper control methods.
In southern Mato Grosso do Sul, technicians found over three hundred of the worms in areas not yet planted to soybeans. The worms were found feeding on volunteer corn from the last growing season and on weed species such as foxtail. The worms are currently being held in Embrapa laboratories until they reach adulthood to confirm they are Helicoverpa. If confirmed, they will be the first confirmation of the worms in southern Mato Grosso do Sul.
Scientists are still working out the best control methods and they are advising farmers that the best time to spray would be late afternoon and early evening when the worms are more active. If left uncontrolled, the pest could cause significant harm to the soybean, corn, and cotton crops in Brazil.