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CROP WATCH

By Staff | Jul 20, 2012

For most of two months we have been glancing skyward hoping to see a large bank of moisture-ladened clouds waiting to dump rain on our respective areas.

Nearly every time it is supposed to rain we have been disappointed. We are finally at the point where we are saying that major rain needs to arrive this week or the top end in yield is gone, and in the worst case scenario the entire crop might be.

This major drought now includes all crop-growing areas east of Colorado and been dry since last July. In this section of the country, we realize that the profile wasn’t full after the warmest winter anyone can remember.

Then spring rains during the last two weeks in late April were the sole reprieve that gave us hope that conditions would return to normal.

All of a sudden the national media is paying attention to our lack of rain and what it has done to the crops. Typically people just go their grocery store or restaurants for food and there is no concern about supply.

Now with South America and North America experiencing severe droughts in the same season we have to ask where any extra grain is being held in storage.

Argentina had its worst drought in 50 years as did parts of Brazil. So where are all the experts predicting the needed grain is going to come from? In an election year, what the USDA is going to try to crash the price of grain. Any efforts on its part may be futile as nature will rule.

On the producer group level, the corn grower groups realize that very high grain prices will lead to demand destruction that could take years to restore.

Flying again

I had the chance to go flying again last weekend to see how the crops looked in central and north central Iowa in comparison to how it looked the week before. Seeing the crop from about 500 feet lets one get a great look at how things are on the ground. What we saw was that more of the sandy areas and shallow soils are expanding in size and degree and to which the crop was hurt. Those areas are generally gone. There was quite a color change in the week’s time with the crop being much yellower. You would have to conclude that is in the serious decline stage.

The beans are having a tougher time closing the rows and in the worst areas seem to be shrinking in size. Since they are now in the R3 growth stage this stress will hurt pod retention and final yields. Several good rains could help hold the late flowers and unfilled pods, so they still have potential.

There were a few storms that raked central Iowa in the past weeks without leaving much rain. From the air one could see corn that had lodged or been knocked down. It seemed to be variety-specific and perhaps tillage-specific. One can’t see such problems from the road, but it will be evident from the combine this fall.

Crop prospects

So how is the corn crop and its yield prospects? Many fields still have their 160- to 200-bushel per acre potential if rain falls in the next week.

The kernels range in developmental stage from just silking to early blister stage. Very few of the fields show much color to the kernels. Those blister stage fields will be dependent on receiving the rain if they hope to avoid a kernel abortion problem.

If rain doesn’t fall in the next week we will likely see the 95-degree temps and high moisture-use levels crash quite a few fields.

Too many of them will likely drop below the 20 percent soil moisture range. Plants that developed roots deeper than 6 feet deep are still staying alive and progressing, but not thriving.

The best dryland corn crops are near Pocahontas, where 2-inch and 4-inch rains fell a few weeks ago.

Soybean yield potential is partially intact. While late beans got hammered by the early frost and early beans often out-yielded them, this season the later maturity beans may have the advantage if late season rains arrive.

It is a good, but somewhat scary time, to go into the fields and pull the husks back to see how pollination fared. Most of the corn planted in April has hit this stage. It appears that corn trying to pollinate during the first blast of 100-degree days had problems in releasing and receiving enough fertile pollen.

Either the base or tip kernel sites did not all get pollinated. Now the May planted fields have to go through this gauntlet and see if they can be successful with pollination. This may be a time when having plants vary widely as to when they tassel could be an advantage in that the pollen-shedding period will be wider than normal.

So far the ear size and kernels site counts look good in the later crop, but it is too early to tell if pollination was successful.

When scouting and evaluating fields the variables that seem to be affecting how the corn crop is doing are: Variety and its drought rating, rooting depth and presence/absence of compactions, soil biology and moisture infiltration measurements, and the use of any biological that increased the number of root hairs.

Crop conference

I had the chance to attend a few hours of a crop educational conference outside of Boone last week. Jerry Hatfield was the presenter, and he shared a lot of his knowledge. What attendees came away with that that technology was great and traits may sound glitzy, but the No. 1 thing that would permit a grower to increase yields and improve productivity was to improve the soil and its health to hold an additional 4 to 5 inches of water that fell in May or June and used in July and August.

Growers who were already doing this are seeing the benefits. Such methods could not be patented or purchased at any retailer so they may not get written about much or advertised, but they will increase in importance.

Saving soil from erosion and having it act as a sponge is crucial.

Diseases spotted

A newer disease or complex that is being detected in many portions of the Corn Belt is causing the root system to turn black and rot away. It looks and acts different than pythium and phytophthora, plus those tend to be wet weather problems, and it sounds more like diplodia, but that is not supposed to attack the roots. No person or research group has identified it yet.

Common rust has been on the corn for several weeks and is easy to identify. A recently identified rust that has been spotted in several counties in north central Iowa is Southern rust. It can be much more damaging and needs to be identified and treated quickly.

Goss’ wilt is still here and different groups are still debating whether the disease can only be a leaf disease or is mainly a stalk and vascular system disease.

There is still too much politics attached to the disease and why it has spread so far so fast. We still need to have a strip test based on DNA and not degradation compounds.

Most of the corn that flash-died and flash-dried last year never showed foliar symptoms. Something had to have killed it before it black-layered.

Be alert to grain problems such as aflatoxin contamination this coming feeding season. Any person or animal who is highly sensitive will have to be alert to all food sources and potential toxin content.

Insects, spiders

There are a few cases reported of soybean aphids being spotted. The high temps have to be detrimental to their survival and reproduction.

The main concern in both corn and beans has to be that of spider mites. These little sap-sucking spiders live and feed on corn and soybean leaves. They suck sap and can desiccate plants if their populations climb high enough.

I pulled the trigger on a few corn fields when we found silver dollar-sized colonies, or larger, three leaves above the ear leaf. Populations like that can kill a corn plant.

Reports about some soybean fields being heavily infected are going to be circulating shortly

Thus any insecticides being recommended will have to reflect the need to control and not boost the mite population.

In Argentina’s drought we saw that the main damaging insect on bean plants were the thrips. Once they built high populations they couldn’t bring the numbers down.

Many farmers sprayed three to four times in trying to control them. I can find higher numbers in many fields and have to wonder if they will have the same effect here.

Bob Streit is an independent crop consultant and columnist for Farm News. He can be reached at (515) 709-0143.

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