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Todd Vagts
Iowa State University Extension
Field Crops Specialist
1240 D. Heires Avenue Office: 712-792-2364
Carroll, IA 51401 Cell: 712-249-6025
Email: vagts@iastate.edu Fax: 712-792-2366

After several nice warm days this last week, the cold north wind is blowing again yesterday. But the extended weather forecast indicates the cold should be short lived. The seven day forecast for northwest Iowa shows open weather with temperatures reaching from the mid seventies to low eighties. Allot of fertilizer went out last week and corn planting is in progress in many fields. We are approaching the optimum time for corn planting, which extends from the last week in April through the second week in May. Research over the last three years at Iowa State University indicates that no significant yield loss in corn occurs until after the 15^th of May. With the warmer days, insects will be emerging or blowing in from the southern states. A sampling of insects that need to be watched for include alfalfa weevil, black cutworms, seedcorn maggot, wireworm and flea beatles.

A few fields of corn have been planted in the area; I would expect that when fields dry up, more activity will occur this week. For those that put corn in the ground as of April 20, the area has accumulated approximately 20 (soil) growing degree-days (base 50).

Once the crop is in the ground, frequent field inspections should occur on a regular basis to monitor stand establishment and crop health. If a stand problem is found, spend the time to determine what caused the reduced stand, whether it may be from seedling disease, uneven seed placement by the planter, rodents, or insect pests. Make it a habit to pull plants and inspect roots. The root system will tell a lot about plant health and general soil conditions (compaction, herbicide injury, disease, and insect feeding). Early inspection of roots may help answer questions later in the season. The following two tables may be useful when inspecting plant populations and stand development.

Alfalfa across the region appears to have survived the winter in pretty good shape, although a few fields have suffered from winterkill of both alfalfa and grasses. Now is the time to be inspecting your fields for adequate survival of forage species. Refer to ISU extension publication PM-1362 for more information on evaluating alfalfa stands.

An alfalfa stand is best evaluated when it is about six inches high. Dig up plants (select one square foot sites per 10 acres) and split the crown. Look for firm and white (healthy) or yellowing and brown (decaying) tissue. More than fifty percent of the taproot should be disease free to be considered healthy.