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CROP WATCH

By Staff | May 26, 2011

Everything seems to be happening at a rapid pace now that the majority of the crops have emerged.

Having the planting season last for about six weeks will make daily progress seem slow at times, but when the weather cooperates there don’t seem to be enough hours in each day.

So now we are at a point where the Iowa crops generally look good, but need to do some catching up and benefit from the heat units that are expected to arrive over the next few weeks.

The latest acreage surveys painted a very good picture as to the progress made in most the Midwest over the past three weeks, but tell of a few areas where conditions have not been as favorable.

Ohio and parts of both the northwest and southeastern parts of the Corn Belt are facing their challenges.

Based on the rainfall that is occurring this week their ability to meet their cropping deadlines will be put to the test.

We have all been wondering where the extra acres will be coming from to meet the usage demands so what happens in those areas plus the Wheat Belt states will be important to overall U.S. grain supplies.

Memorial Day is almost here, a holiday that typically signals the true start of summer and all of its activities.

A lot of work has to be completed during those months, but it can also be one of the most enjoyable and beautiful parts of the year.

All those colors, tastes, and sounds that we always get to enjoy – fresh sweet corn, tomatoes, strawberries, the 4th of July and picnics.

Storm Weather

A number of meteorologists and the National Weather Service seem to have predicted a wildly active tornado season. They seem to be correct as small Iowa towns, and large urban areas such as St Louis, Tuscaloosa, Minneapolis and now Joplin got hammered.

For years we wondered why the bigger towns and cities seemed to be immune from attack. The twisters also seemed to leave churches and hospitals alone. Now after the damage in southern Missouri this past Sunday every place and building seems to be fair game. Does that mean more hail storms this summer?

Crop growth

Most of the corn as of mid-week was still only at the V1 thru V2 growth stage. It will have to hurry up to match the nearly knee high by June 4, which is what we have seen in the best years during the last decade.

As we get into late May and early June, when the nighttime temps are supposed to be warmer, the rate of growth should pick up.

Most of the soybeans are either still emerging or are only in the VE thru unifoliate stages. Cool temps and lack of sunlight on many of the days is slowing their pace of growth.

The accompanying low soil temps are going to be lowering the rate of nutrient release from the soils. It is at times like these when row-applied or foliar fertilizers can have the largest effect on the small plants.

The application of in-furrow-applied biological to boost nutrient availability can also help.

Last week I mentioned that many growers were seeing a percentage of their corn plants were having a hard time emerging and beginning their growth.

A variety of things seemed to be going on. One of them was that in spite of good seed depth and lots of moisture in the profile, the seeds appeared to have been placed in dry soil.

Those seeds in question germinated and began growing about a week later than their counterparts within the same row.

How or why the moisture didn’t move up to swell the seeds has still not been answered.

In other fields there are still seedlings that have expanded their leaves and are roped out without having reached the soil surface.

Their push is gone and will continue to decay. In most cases they look like they were battling a heavy crust, though in most cases no crust was present.

Weed control

The percent of farmers that applied residual herbicide increased again this season.

Some of those efforts were challenged by the wet weather and plans tweaked a bit to get the products or a substitute applied.

A quick inspection of the degree of control can give a first impression of how good the control was, but a better and more accurate impression can be gained after we get several weeks of heat.

A number of products that can go on “early post” will be applied over the next few weeks, so the weather has to cooperate during this time period.

Most of these post-applied products have applications guidelines that are growth stage specific, so being able to correctly judge the size of the corn plants is important in getting things right.

Remember that with herbicides the leaf is counted only if its collar is fully exposed.

The normal growth rate for corn plants this time of year is two leaf stages per week. Later in the season that could accelerate to 2.5 per week.

In soybeans after they have reached the first trifoliate stage they form a new set of leaves every 3.8 days.

In the move back to the use of more residuals more planning and forethought will need to be used to eliminate or minimize all cracks that any weeds may try to sneak through.

The advent and addition of P450 safeners to the herbicide arsenal helps the system greatly and makes good weed control much more possible.

The challenges that will be posed by nature and the wide genetic based that many weeds possess as they develop tolerance or resistance to what herbicides we may chose to use will likely always be with us.

It will be interesting to see what interaction between weed populations and used cover crops are uncovered as that research is done.

Another angle that exists is that there are slated to be a few new herbicides appearing in weed trials this season.

New ones have been rare the past seasons as the reward for firms trying new materials was slim.

Insect pests

Due to the variation in plant size and differing locations within the state several pests may be appearing now or expected to be around over the next weeks.

The first might be corn flea beetles going after small corn plants. They were last seen as a problem around 2002 or 2003 in a drier spring when large numbers were found stripping corn plants.

Their ability to transmit Stewart’s Wilt is what causes them to be of concern. One has to scout for them during a calm, warm and sunny mid-day time period.

The next would be bean leaf beetles. With such a high percent of the beans emerging during the same time period, their population should be spread out rather than concentrated. The winter conditions were deemed not favorable for their survival in northern Iowa.

Black cutworms are worth watching for on no-till fields that supported the growth of any mustard plants. Due to wind direction this spring they are more likely to appear in eastern Iowa than out west.

What to keep track of

Over the next few weeks operators will have to stay on top of all weed populations as well as monitoring the growth of the crops.

Those who listened to crop or fertilizer advisors over winter and want to use tissue testing to monitor micro-nutrient levels may want to prepare to take early samples for analysis.

That would mean pulling whole plant samples prior to the early application window in one to three weeks.

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

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