DES MOINES, Iowa - Late-planted crops and extreme weather have played havoc with corn and soybeans in many regions, creating such problems as pest pressure, ear rot, lodging and other challenges. For these reasons, late-season scouting until harvest can greatly benefit growers, says an expert at Pioneer Hi-Bred, a DuPont business. Such scouting can lead to better harvest management and provide keen insights into 2012 seed decisions.
"Each region of the U.S. has experienced some type of stress this growing season," says Chuck Bremer, Pioneer agronomy information manager. "For some, that means a late start for planting due to excessive rains while others experienced stress in the form of drought."
Late-Season Corn Management
"A later planting start, like those across the Northern and Eastern U.S., invites the threat of frost before reaching black layer," Bremer says. "Should this occur, growers could consider using their crop for high-moisture corn or silage for their livestock."
Drought conditions plagued areas across the South and Southeastern U.S. Growers in these areas should watch for Aspergillus flavus and Fusarium ear rots.
"The best way to avoid load rejection at the elevator due to Aspergillus flavus is to adjust the combine settings," Bremer says. "If growers suspect the disease, they should adjust their combines to reduce cracking of the grain. This includes adjusting the cylinders, turning up the air and adjusting the screens."
If the crop goes into feed, Fusarium can cause complications on the backend. The disease can continue to grow in storage following harvest and be can be toxic to livestock. Continuous monitoring is necessary.
Growers could possibly anticipate lodging in areas where crops were planted in less than optimum conditions and encountered drought stress. "Growers should pinch their stalks," Bremer says. "If the plant shows stress, growers need to schedule those fields for early harvest, if possible."
Another issue that continues to expand is Goss's wilt. The disease originated in Nebraska and continues to expand into Iowa, Wisconsin, Illinois and surrounding states. Plants with this disease commonly have lesions with wavy margins. The margins of lesions have a water-soaked appearance with black flecks within the lesions that cannot be rubbed off the plant tissue. Growers encountering the disease should consider a hybrid with Goss's wilt tolerance next season.
Late-Season Soybean Management
The Northern U.S. west of Lake Michigan has potential to see soybean aphids. According to Bremer, the pest is surfacing in soybean fields in this region. The threshold for an application is 250 aphids per plant up to the R5 stage.
Other risks for soybeans include spider mites. Indiana, Illinois, Missouri, Iowa and some areas across the North are encountering this pest. Double-crop or late-planted soybeans have greater potential to host spider mites. Soybeans planted early are past the peak feeding time for spider mites and therefore, are less susceptible.
"Spider mites thrive in hot, dry weather," Bremer says. "Growers should scout the edges and corners of fields first, shaking the bottom leaves over a sheet of white paper. If a grower sees 'moving dirt' they may have spider mites."
As the season progresses, growers in Illinois and Indiana should scout for sudden death syndrome (SDS) due to rains early in the growing season.
"SDS will show up in fields with prime soils. The plant will have yellowing and defoliation in the upper leaves," Bremer says. "Typically the disease is confined to an area and likely will not take an entire field."
If a grower sees SDS in a field, he or she should consider choosing a variety with high tolerance ratings to the disease; Pioneer®brand varieties offer growers a choice in level of SDS tolerance.
"Each growing season offers growers the opportunity to reflect and learn lessons," Bremer says. "It's a good time to gather data and use it to make informed seed purchases for the 2012 growing season."