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CROP WATCH

By Staff | Aug 23, 2013

This has been one season where you don’t have a clue as to what extreme in weather is next to arrive.

Floods, late-season snow, abnormally cool and cloudy days, incessant rains and now the opposite which is a severe drought.

At the start of this week most people had watched and listened to enough weather predictions and heard that the 90-degree temperatures are returning with scant signs of receiving any rain.

That just might cook a lot of the crops given their shallow roots and already dry profile. Both corn and soybean crops, as well as pasture crops already under stress for quite a few weeks may not have the ability to tolerate too much more of the same.

The markets seem as unsettled as they have ever been which may be related to how disconnected Chicago and Washington’s perspective on the state of the 2013 crop status.

The more people we visit from the local area or elsewhere that have traveled to different states to view and walk the crops, the more have a different opinion than NASS.

Part of that disconnect was made visible when updated figures were released last week on prevented planting acres, where USDA finally admitted were too low and misleading.

Details on PP acres

So the actual updated figure is now at 3.4 to 3.6 million acres. The list still needs and should to be more complete by giving the county-by-county figures for acres that are now either sitting black or planted to a cover crop. Thus far what has been given is counties with more than a certain percentage of PP.

We know two major counties in north central Iowa totaled more than 50,000 acres alone. And those two were not the two hardest hit. Then, on a Midwest-wide survey. Anyone who makes the trek to the Twin Cities can see that everywhere east of Iowa Highway 15 in southern Minnesota was affected greatly by the wet May and June.

What is not counted are the acres planted to corn or beans that are so far behind in development that their chances of reaching maturity and drying down before frost are low.

This situation is causing different people to use the old phrase of 40-40-40 corn again.

Shallow roots

A problem all season has been the lack of deep rooting on the corn crop. There were many factors that contributed to this, and we will have to figure out which ones we need to focus on and try to correct next season.

If it is planting depth, that should be easy to remedy. If it is lack of good soil porosity, that will take more time and a long-term program to build soil organic matter and tilth.

If it’s due to excessive weight on the machinery, as quite a few growers noted, then they will have to make changes in equipment used or tires versus tracks.

The move to central-fill planters and how full they should fill the big tanks will be a topic that will be brought up. Some of those questions will be answered if and when growers track the yields of select rows at harvest time and make their comparisons.

After the dry conditions of 2012 many corn growers knew they wanted to plant at least 2 inches deep. Though they had the best intentions in mind, when they got to their wet fields this spring they often found out they had to goose their tractors a bit to get their bigger and heavier planters through the wet spots.

This raised their planting depths to about 1 inch, which ended up causing a major decrease in total roots formed.

Then if they had any measurable amount of rootworm feeding each lost root increased the degree of drought effect the plant suffered.

Corn prospects

The big question now is how will the yields of the Midwest corn fields turn out? That answer will depend on how well each field has been managed and how much Mother Nature helped each with timely rains. For quite a few weeks we have been able to observe differences in plant coloration and presence of, or lack of, leaf streaking.

Besides rooting amount and depth, making sure the plants were as physiologically efficient and were not lacking in any nutrients or micronutrients has been important.

I was over in one of the best part of the state on Monday, where yield prospects on their well-drained and on-time planted corn was very good a few weeks ago.

Their corn still looks good, but many on the Tama soils are yellowing badly and seem to be on a steep decline. Any foliar or dribbled-next-to-the row fertilizer applications have helped as have the use of any micronutrient mixes.

More growers are now recognizing that the corn crop is yellowing. Considering that much of the crop was planted four to six weeks late, this is an ominous trend since a high percentage of the dry matter still needs to be deposited.

We used to cause this anthracnose top die back and some may still be that. We think it is more a combination of Goss’s wilt and fusarium infection of the pith down in the crown region. The sieve plates at each node have been turning darker brown each week if you have been watching for this.

Soybean potential

At this time, the late-planted bean plants appear to be challenged with the number of pods they are forming. The later any burning herbicide was applied and the worse the burn was, the lower the pod count appears to be.

The same also applies to what is occurring due to the degree of drought each field is going through. Any extra management that was used with the purpose of adding branches and flowers looks like it is working.

In most of the fields planted on time there are now 30 to 45 two- and three-bean pods that are in the process of filling. There are still 30 to 80 small pods and flowers that could still develop if rain arrives in the next week. After that point, many of them are likely to fall off.

The number of pigweed species surviving in each field is becoming more apparent each week as they poke above the canopy. It looks like there are an unlimited number of variants in that weed family.

The ones that appear most capable of surviving herbicide are the hybrid that stands 3 to 5 feet tall, has a large diameter reddish root, have a red stem and long, smooth leaves.

Be aware that such weeds have been releasing pollen that could have pollinated surviving pigweeds growing in neighboring corn fields.

Those offspring could be the ones emerging in next year’s bean fields.

Bugs of the week

In a year where aphid numbers are staying low, we have continued to scout bean fields to determine what other threatening insects were going to appear and multiply.

Last year is was spider mites due to the hot temps and dry conditions. This year when we have had a severe cool drought it appears that thrips may be the wild card insect.

These are small, torpedo-shaped, yellowish-green insects that like to suck sap out of the bean leaves.

They are not normally thought of as yield damaging. Two years ago bean growers in Argentina who were suffering through their worst drought in 50 years, the thrip populations grew unchecked and they damaged every leaf, plant and yield.

Attempts to control them with three to four pyrethoid applications failed. Their damage appears similar to that done by mites as the leaves take on a silverfish scratched appearance and have less photosynthesizing ability.

If you are scouting for them recognize that the white- and black-striped thrips are predator mites that help the situation.

Pirate beetles can also serve as thrip predators if they can catch the fast moving pests.

Say another prayer that the rains make it 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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