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CROP WATCH

By Staff | Aug 13, 2010

Does anyone else get the impression that we now live in a rainforest area? Nearly every day lately we watch the black storm clouds build during the late afternoon and by news time thunder cracks and rain falls in thick sheets.

With the thick canopy in most fields and high humidity each day the wild theory from the meteorologist at Southern Illinois University who postulates that the daily evapo-transporation sets up its own weather systems doesn’t seem so wild.

Most places within the state have now garnered a full year’s worth of rain already and there are nearly five months left in 2010. In another month we will be wishing for enough dry weather that we can have that two-inch soil moisture deficit going into harvest that will absorb the small rains quick enough to not delay harvest.

These 90-plus degree days seem hot, but they are just a matter of getting used to. Years ago it always seemed that those were the days when the hay or straw was ready to bale, so like it or not that was the main chore of the day – if it wasn’t baling, it was the day to set forms and pour concrete. There was nothing like a little exercise to break a sweat.

If it were not so hot, this is typically one of the nicest times of the year. The spring rush is now over with. Most bug worries are over with, even though this is normally aphid scouting and spraying time in Iowa.

All of the ladies’ flowers are in full bloom. The last part of the sweet corn season is still here and all of the accompanying items out of the garden. The last few nights we have sat down to some good ol’ Iowa-raised beef burgers crowned with fresh tomatoes, fried eggplant, watermelon and crookneck squash. In any fancy restaurant such faire is tough to beat.

Last week was the time for the Minnesota Farm Fest. It is a smaller and folksier version of the Farm Progress Show. They still play their polka music in booths or pump it over the loud speakers as well as serving brats and kraut at several of the stands.

On my drive north it was apparent that the farmers in Minnesota are growing the crops, for which they’ve wished for the last few years. Mother Nature is delivering plenty of heat units and enough rain in timely amounts for farmers in Minnesota, North Dakota and Wisconsin.

Those people, plus farmers in northwest Iowa, have the premier crops this season. What is even better and making bankers, farmers, and businessmen happy is that it comes at a time when prices seem to be rebounding.

Row crops

The continuous wet conditions, coupled with soils that never froze to help fracture shallow compaction, continue to cause problems with this year’s main crops. The list of problems have to include limited rooting depth, poor moisture infiltration, anaerobic rooting zones, reduced nutrient uptake and potential loss of nitrogen.

What is very common now in fields south of U.S. Highway 20 are yellow cornfields and soybean fields dotted with areas of brown plants. In many of those yellow fields growers recognized that something needed to be done, but in many cases they either did not have the equipment to apply sidedress nitrogen, or didn’t have enough dry weather to get the job completed.

When the combines roll, they will likely find large enough per acre yield losses that they could have afforded to buy or hire such equipment. Having dry weather would have still been a challenge.

The brown beans are due to sudden death syndrome, which we had forecast to reach “worst ever” levels.

After it shows up there is nothing that can be done for the fields except make plans for 2011 and beyond. There does appear to be a large varietal difference that growers will recognize and select with next season.

To confirm such a diagnosis one can go into those spots and pull plants. Squeeze the nodules and they should be squishy with a yellowish inside. At some point a bluish slime will be growing on the exterior of the root.

Next season make sure you include a product such as Saber X seed treatment at planting. The trichoderma fungus works to kill the fusarium before it infests and provides season-long control.

A second beneficial fungus from another source appears to also offer very good control of both SDS and white mold. Anyone who can get me a decent supply of the mouse dropping-like sclerotia from 2009 problem fields for screening work, let me know.

There are a few more biological products close to being commercialized that are originating from several well-recognized research programs. Watch for any pseudomonad products also. Educate yourself about them as they will be very valuable in the future.

As to how the corn crop is doing as far as grain fill, the intense heat with warm nights is causing problems that is only being recognized by scouts and farmers who actually scout their fields.

What happens with these warm nights is that starch formed during the days is burned off at night. Thus the kernels depth is reduced and yields will be lowered. These shallower kernels are now evident in many fields where multiple problems have been at play.

What has been visible is that fields that received either a micronutrient application or a fungicide application, or both, are much greener and have deeper kernels. It looks like it will be money well spent.

By this week it was easy to find ears with kernels that were 50 percent to 80 percent dented. This is earlier than normal and indicates that black layering and the end to grain fill is only about two weeks away.

While seeing this dent is normally a good sign, having it happen so early means that heat units and reduced grain filling days will be lost. Remember that such problems within the U.S. and other places like China and Russia are the reason that grain prices have risen from their depths of two to three months ago.

It creates a sense of optimism that most had not expected in what looked like a blue marketing season.

Soybean scouting

This week’s soybean scouting is detecting several normal leaf diseases as well as several regular and irregular insects. The normal leaf/stem diseases include Septoria, downey mildew, frog eye spot, and anthracnose, plus several bacterial infections.

The time to treat the fields with ground rigs and get good enough coverage is mostly passed. With septoria being a lower canopy disease, trying to get decent results this late is difficult.

Aphid numbers are still climbing slowly and may not reach high enough numbers to cause problems, but we learned to never count them out. Scouts are now finding the larvae from all of the little moths that were flying at night the past two or three weeks and they are chewing on the leaves, sometimes consuming enough tissue to be worrisome.

We can’t ignore them and hope they go away.

Another insect that may not get enough attention are all the small white flies. Brazilian researchers have found that they spread a viral disease called hasta necrosis that hurts bean yields.

I don’t know of any who has studied them very well to see if they vector any disease in the U.S.

CRW

The corn rootworm beetles can now be found in many corn fields. It seems to be mostly the western ones that have become numerous. Having them show up is not unusual, but they normally appear along U.S. Highway20 around July 3 to 5.

In a year with an excess of growing degree units why are they appearing four to five weeks late?

Knowing that Bt toxin levels decline after the V4 corn growth stage, their late appearance questions the ability to use that technology to effectively control them using the Environmental Protection Agency’s low dosage strategy.

Tours

There will be quite a few field days over the next month. Be sure to attend those that tell about new management steps or tools that can be used to better deliver fertilizers or fertilizer efficiency.

Keep an open mind about some of the plant protectant products that could offer better weed or disease control.

P.S. Send sandbags and life boats to the Ames area.

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