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It’s slow and go for crops thus far

By Staff | Jun 19, 2009

Experts say it is time to begin being aware that soybean aphids could be headed toward fields within the next couple of weeks. One sign to watch for is predators, such as ladybugs prevalent in the field.

Cooler, wet weather that seems to be stuck over the state this past week is affecting plant growth in some areas of the Farm News’ coverage counties, and is not affecting them in other areas.

Southwest counties

Mark Licht, ISU Extension field agronomist for the counties of Ida, Sac, Calhoun, Crawford, Carroll, Monona and Greene, said that overall he doesn’t think the cooler weather is affecting crops in his area quite yet.

“The growing degree days are only slightly behind normal for the growing season thus far,” Licht said. “Yes, in some cases the cooler weather is slowing root development and therefore nutrient uptake so there is some yellow or purple corn out there, but the recent rains and expected warm weather for this week should be of tremendous value to both the soybean and corn crop.”

Corn in Licht’s area is at the sixth- to seventh-leaf stage. Soybeans, he said, are anywhere from the cotyledon stage up to the fourth-trifoliate. Overall, he said, both crops are about where they should be for mid-June.

John Holmes, ISU Extension field agronomist, said that due to the recent cooler, wet weather these past few weeks, herbicides are working a little slower than normal. Here some grass growing in a bean field south of Fort Dodge is beginning to show signs of the herbicide working.

When comparing the 2009 spring to 2008 spring, Licht said the crops in his territory have tremendous potential.

“That is considering that last year much of the eastern half of my area was looking at extreme wet conditions and some places soybeans had not been planted yet,” said Licht. “This year the eastern half of my area has received some rain, but not as much as last year.”

Replanting, he said has been minimal at probably less than 2 percent and the crops are looking really good. The western half of his area has been running short on rainfall this year compared to normal and with that combined with well-drained, light soils they have needed the rain this past week.

“But the crops still look good with minor case of anhydrous burn or uneven plant development due to variance in rooting environment,” said Licht.

Licht said producers in his area should start digging some roots to check for corn rootworms in the next few weeks, especially in refuge acres or where the corn is having problems.

Soybeans, Licht said in the next coming weeks should be seeing the first generation of the bean leaf beetle and the soybean aphid should be soon to follow that. For those two insects, Licht said the best scouting method is to just get into the field and start looking at leaves.

Northwest counties

Joel De Jong, ISU field agronomist covering the counties of Lyon, Osceola, Sioux, O’Brien, Plymouth, Cherokee and Woodbury, said the cooler, wet weather in his area has slowed the growth and development of all plants with some beginning to show the yellowing of inactivity.

Up until recently, De Jong said, in some areas of the northwest corner were still quite short on moisture and the cooler temperatures were a welcome relief, reducing stress on some of those fields.

De Jong estimates that growth is still probably about average to maybe just a bit behind.

“We got off to a better start that last year,” said De Jong. “Planting was timelier into better (soil) conditions and stands of corn are better, but right now we are struggling to take the next step and grow rapidly.

“However, with wetter conditions, we struggled last year, too. So, I would say that overall we are better off than at this time last year.”

Producers, De Jong said, should be scouting their smaller corn looking for wilted and dying corn plants caused by black cutworms. They should start by checking where fields were weedier early in the year, in low lying areas and in areas that have a cutworm history.

In alfalfa, he said to get out there with your sweep nets and watch for potato leafhoppers, although there haven’t been any significant reports yet, the season is just beginning.

“We have been way below normal for rain in the northwest corner this spring, and some fields have suffered from it,” said De Jong. “But, they are now starting to develop those root systems to start taking advantage of subsoil moisture in storage.

“We had a lot of fields that did not get anhydrous applied until spring and with dry conditions I have observed quite a bit of anhydrous burn, but we are starting to take off with corn growth.

“Weed pressure has gotten a lot worse lately, many fields need to be treated. Although some fields have been sprayed, weed competition likely cost us quite a few bushels in several northwest Iowa fields this year.”

Northeast counties

The counties of Hancock, Cerro Gordo and Franklin are just a few of the counties George Cummins, ISU field agronomist, covers and he says so far this spring has been yet another trial for many producers.

“It’s been another challenging spring,” said Cummins. “We’ve had a lot of starting and stopping of planting this year. We started out with good soil conditions that the rain later hindered. What should only take 10 to 14 days to complete took six weeks to accomplish.”

Cummins said row crops are running behind normal in heat units and are continuing to fall behind. Flooding has also been a major problem for producers in his area.

“We are above normal in moisture,” said Cummins. “We have had some spotty storms with some hail damage in areas and are seeing some erosion issues as a result of the rain.”

Compared to last year, he said that although he has seen a lot of flooding there hasn’t been as many replanted acres this year, however.

In his coverage area just north and west of Mason City, Cummins said crops seem to be in good shape as that area has had less rain and more days fit for getting the crops in and for them to grow.

Black cutworms were seen flying in the first week in May and last week, scouting had began to look for damage and so far, Cummins said there has been no major damage.

Aphids he said have been found in northeast Iowa soybeans and they are expected to begin migrating towards the west, as they have in previous years. He urges producers to begin scouting for aphids in soybeans.

To get a close up look at the crops in Cummins’ area, he recommends attending the field day at the ISU research and demonstration farm in Kanawha at 9:30 a.m. June 25 with a program on soybean traits, corn production, soybean aphids and crop problems.

Central, southeast counties

John Holmes, ISU field agronomist for the counties of Humboldt, Webster, Hamilton, Hardin, Boone, Story, Marshall and Tama, said his area on average is short about 115 growing degree units since May 1, which he figures to be about five to seven days behind normal.

One issue concerning many fields in his area, Holmes said, is the delayed effect of herbicides due to the recent cooler, wet weather.

“We’re mainly seeing herbicides working a little slower and plants are growing a little slower,” said Holmes.

Many continuous corn fields are very un-even throughout his region and this he said is not necessarily tied to a nitrogen deficiency, but rather a rotational effect and with some heat they will begin to improve.

Overall, Holmes said corn and soybeans are looking good, but are just a little behind for this time of year.

When it comes to pests, Holmes recommended continued herbicide spraying. For alfalfa, he suggests scouting and sweeping for potato leafhoppers.

Holmes is also expecting the aphid migration from the northeast, adding they have already been spotted near Ames.

“Be aware they’re there,” Holmes said of aphids. “You can scout for them as easily as looking for predators, such as ladybugs (by) flipping flip that leaf over and counting.”

Another soybean pest that would be timely to look for he said is the soybean cyst nematode.

European corn borer moths have been pretty prevalent and producers should be looking at their corn for feeding and with corn that had been re-planted, Holmes suggests, to be on the look-out for black cutworm feeding as well.

Contact Kriss Nelson at jknelson@frontiernet.net.

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