Water Everywhere!
The past ten days has brought heavy rainfall across nearly all of central and north central Iowa. Fields flooded from rivers and streams, ponds filled, and all the soils in low-lying parts of fields were completely saturated. What can farmers expect to happen to the crops planted in these areas? Crops in standing water were expected to survive roughly 48 hours. You can probably already see the areas that have died. If corn survived, the kernels will be light and the potential for mycotoxins in the grain goes up. Soybeans will have moldy pods on the bottom of the plants and small seed at the top of the plants. Crops in saturated soils will see increased root diseases and other late season problems. In corn expect stalk rot to increase in saturated areas. Soybeans will most likely also see diseases increase.
SDS Update
Nearly every soybean field has some sudden death syndrome. Unfortunately some seem to have a lot more than others. Remember that SDS is more predominant in wet areas and that infection occurs early in the season. The level of SCN infestation also affects how much SDS is in a field. Higher levels of SCN equate to more SDS in the fall.
Soybean Rust Update
Watch the soybean rust progress at www.sbrusa.net. You can read the Iowa commentary by clicking on “state information.” The most recent find was in a sentinel plot in NE Oklahoma – just a stone’s throw from SW Missouri. The latest risk assessment from Dr. XB Yang suggests that the risk of a DAMAGING outbreak of soybean rust is low. The sentinel plots are being scouted more frequently because of the increased risk of rust getting to the state.
Top Die Back in Corn
Drive down any road and you’ll see corn that has brown leaves on both the lower and the upper portion of the plant. The brown lower leaves have been common for 2-3 weeks and are a reflection of a nitrogen shortage and of normal maturity. The top die back we’re seeing is most likely due to anthracnose top die back. Watch for anthracnose stalk rot in these fields as well.
Training Opportunities Still Available
The FEEL lab still has several excellent schools available yet this year. Take a look at: http://www.aep.iastate.edu. Among those schools are the Manure Management Clinic, an alfalfa clinic, a late season crop diseases school, the Iowa Drainage School, and a soils clinic.
To Learn More...
If you would like additional information on the above topics or have other crop-related questions, contact Field Specialist John Holmes.
Additional Sources
Previous 2007 Issues
2006 Issues
2005 Issues
2004 Issues
Crop news from other Iowa field specialists
John; Meridith
9/2/2007