April 18, 2013
New Insect Caused Significant Crop Loses in Western Bahia
As farmers in western Bahia finish harvesting their 2012/13 soybean crop, they are reporting disappointing soybean yields due to dry weather and the infestation of a new leaf-eating caterpillar in the region. Western Bahia and the neighboring states of Maranhao, Piaui, and Tocantins are considered the new promising agricultural frontier in Brazil.
According to data from the Irrigated Agriculture Association of Bahia (AIBA), approximately 80% of the soybeans in western Bahia have been harvested and the regional soybean yields are averaging 37.6 sacks per hectare (2,256 kg/ha or 32.7 bu/ac), which is 32% lower than the 55 sacks per hectare expected at the start of the growing season (3,300 kg/ha or 47.8 bu/ac). Corn yields in the region are also expected to decline to 125 sacks per hectare (7,500 kg/ha or 115 bu/ac), which is down 22% from the initial expectation of 160 sacks per hectare (9,600 kg/ha or 148 bu/ac).
The primary reason for the lower yields is dry weather during January and February which not only increased moisture stress on the plants, but it also led to a tremendous increase in the number of caterpillars in the soybean, corn, and cotton fields of the region.
The leaf-eating caterpillar is from the Helicoverpa moth, which was first found in the region two years ago. It has also been found in the neighboring states of Maranhao and Piaui. While the insect is new to farmers in northeastern Brazil, it is a familiar pest in other parts of the world where it is called by various names including corn earworms or cotton bollworms.
With the harvest of the corn and soybean crops winding down, cotton producers are concerned that within 30 days their cotton crop will be the only remaining crop in the field and it could be an attractive target for the pest. AIBA has already estimated that cotton yields will decline 15% from initial estimates due to losses caused by the insect.
In addition to lowering the yields, controlling the insect has been very costly for farmers in the region. Cotton farmers have had to increase their insecticide applications at an additional cost of US$ 80 up to US$ 350 per hectare. The increase in insecticide purchases is expected to total US$ 92 million. Total loses in the region due to lower yields and increased cost associated with the pest is estimated at R$ 1.5 billion.