March 4, 2011
Heavy Rains in Parana Slowing Harvest, Increasing Insect Feeding
Wet weather continued to impede the soybean harvest in many areas of Brazil including the state of Parana, which is the second largest soybean producing state in the country. Soybean producing regions in northwestern Parana such as Umuarama, received twice their normal rainfall during the month of February. Normally by early March, the soybean harvest in the region would be half completed, but this year only 20% of the soybeans have been harvested.
Farmers in the region do not think the yields have been compromised as yet, but continued wet weather could negatively impact the quality of the seed. Early harvest reports indicate that yields are in the range of 50 sacks per hectare (3,000 kg/ha or 43.5 bu/ac), which is better than the long term average for the region which is approximately 45 sacks per hectare (2,700 kg/ha or approximately 40 bu/ac).
A concern for some of the later maturing soybeans in the region has been the tremendous increase in the stink bug populations. Stink bugs feed on soybeans by burrowing into the developing pods and soybean seed. They inject a toxin into the developing seeds in order to suck out the juice and the result is deformed pods and seeds and as a result, poor quality seed and lower yields. Their feeding activity also offers a pathway for other pathogens such fungal organisms to enter the seed resulting in even further damage.
The insects can be controlled by insecticides, but the nearly constant wet weather has kept the sprayers out of the fields and it has reduced the effectiveness of the insecticides that have been applied. These poorer quality seed are also discounted when they are sold to the grain elevator.