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May 30, 2013

Soy Yields in NE Brazil Disappoint due to Dry Weather and Pests

Several extended periods of dry weather and excessive pest pressures have resulted in disappointing soybean yields in the northeastern Brazilian region known as MaToPiBa. This is the area where the four states of Maranhao, Tocantins, Piaui, and Bahia meet. Farmers have been migrating to this region of cerrado vegetation in recent decades to take advantage of cheap land prices and proximity to ports in northeastern Brazil.

While the area may be attractive due to cheap land prices, the MaToPiBa borders on the semi-arid region of northeastern Brazil. The summer rains start later here than in central Brazil and they end earlier resulting in less total summer rainfall. Irrigation is the best way to insure good yields, but limited groundwater resources restrict the amount of irrigation possible in the region.

The soybean acreage in the region expanded 7% during the 2012/13 growing season, but the soybean production declined 15%. Rainfall in the states of Maranhao and Tocantins was sufficient for normal crop development, but the rainfall amounts in Bahia and Piaui were significantly below normal during the growing season. In these two states much of the soybean crop encountered two episodes of dry weather, one in December and the other in February. These two combined episodes resulted in up to 60 days without rain or nearly two thirds of the soybean growing season.

Another problem for the soybean crop in the region was a relatively new pest in the region, the Helicoverpa caterpillar, also known as a corn earworms or cotton bollworms. The insect was discovered in the region two years ago, but the 2012/13 growing season was the first year that it caused significant damage to the soybean, corn, and cotton crops. It is estimated that the caterpillar reduced soybean yields by as much as 5 sacks per hectare (300 kg/ha or 4 bu/ac) in spite of the fact that some farmers applied 13 insecticide applications in an attempt to control the pest.

The state Plant and Livestock Protection Agency of Bahia (Adab) has set up a series of experiments on ten different properties in the region to test the effectiveness of new chemicals to control the pests.

The same insect was also found in soybean fields in Mato Grosso and Parana. Scientists in those states are worried that the safrinha corn crop in both states could serve as a bridge between soybean crops and aid in the spread of the insect. If the insect continues to spread, there is a potential for significant damage being done to the 2013/14 soybean crop in both states.

The combination of dry weather and insect pressure lowered soybean yields by as much as 30% in the hardest hit areas. The region as a whole lost an estimated 2 million tons of potential soybean production during the 2012/13 growing season due to these two problems.