Wednesday, December 03, 2008

by Gordon Wolf

The corn and soybean crops are doing well in west central Iowa, especially considering the conditions in the spring, according to Mark Licht, Northwest Extension Field Agronomist based in the Carroll County ISU Extension office.

Licht serves Ida, Sac, Calhoun, Monona, Crawford, Carroll, and Greene counties.

"The corn is running nearly two weeks behind the past several years. Corn diseases and insects are at low levels at present although the weather conditions are conducive for potential foliar disease outbreaks," said Licht. "Western bean cutworms are at very low levels compared to past years and therefore should be of little concern."

Soybeans are running about a week behind normal and in some places are 12 to 18 inches shorter than normal, Licht reported.

He said soybean aphids have become problematic across most of west central Iowa over the last week and that bean leaf beetles have reached the level for second generation control in several fields.

"For both corn and soybeans, another pest is causing severe defoliation on field edges. That pest is the grasshopper," said Licht. "Defoliation may be severe enough to warrant control at least at the field edge since the grasshoppers can continue feeding through August."

Licht reported that timely rains have been received.

"This is likely a blessing since both corn and soybean root development was slowed in May and June due to cool, wet conditions," Licht explained.

"When field soil moisture is continuously above field capacity, there is no need or incentive for plant roots to grow deeper in search of moisture," he continued. "I feared a mid-season dry period due to potential crop stress being compounded with poor root growth. Nonetheless, moisture has not been in high demand in 2008."

Licht also reported that replanted crops are looking pretty good, although they are much further behind.

"Some corn was planted into late June and soybeans were planted into early July. There is some potential that these crops will not make it to maturity due to an early frost," he stated. "Part of that depends on the maturity that was available at the time of replanting. We will have to wait and see how they do."

West central Iowa experienced several hail and wind storms.

"I think that there are spots in all seven counties that I cover that have had some degree of hail damage at some point this growing season," said Licht. "The worst hit area stretches across central Crawford County to southwest Calhoun County.

"Wind damage has been problematic due to straight line winds from central Carroll County through southwestern Greene County," he continued. "Damage estimates due to straight line winds and hail are as high as 90% yield loss in the worst hit areas but generally damage was limited to less than 30% yield loss."