In order to avoid interferance with proper ear set foliar fungicides are best applied at brown silk.The shot above comes to you compliments of the Pioneer Agronomy Services Department - Johnson Iowa.It shows what can happen if foliar fungicides are applied to corn prior to tasselling.

The heavy spring rains we experienced back in early June are but a fading memory but the damage they caused our soils is still very evident.Water is a forceful agent.As it strikes the ground it breaks down soil aggregates causing them to lose their structure.In many ways the damage rain droplets do to soil structure can be likened to the explosive nature scud missles do to buildings.
As soils compress from the heavy weight load of water they lose their oxygen supply.Without sufficient oxygen root growth slows.Cooler soil temperatures and fungal pathogens further restrict root growth.With time a significant differential in top growth becomes evident between areas of fields that have the best internal drainage to those that have the worst.This can be noted in the top photo.This is going to lead to considerable variation in silking across fields and considerable variation in harvest moisture.This will also pose a considerable challenge for growers who are contemplating applying a foliar fungicide.To avoid potential interferance with pollination and ear set foliar fungicides are best applied at brown silk.

Do you notice a difference in the nodal root system of the two corn plants shown above? The plant on the left was grown in a simulated moderate weed pressure environment where the weeds grew 4 inches from the plant.Notice how its nodal root system is shorter and how they are growing straight down almost as if it was trying to get away from any neighbouring weed competition.In reality corn plants do read their environment and they will respond to it.It has been discovered that it is the reflected light ( called phytochromes ) that comes off nearby competitive weeds that makes the corn plant react in this manner.The corn plant on the right was grown in a simulated weed free environment.As you can see its nodal root system is much more prolific and reaching out in all directions.It will be able to interface with more soil volume thereby having greater opportunity to extract more water and soil nutrients from a greater volume of soil.This experiment helps shed some light on why researchers
are adamant that you need to keep the crop weed free from the 3 true leaf stage until the 8 true leaf stage in order to maximize yield.

Spray timing trials like the one shown here are conducted each year by the University of Guelph to document the amount of yield loss in corn if weeds are not controlled between the Critical 3 and 8 leaf stage.The corn in the first shot above was sprayed at the ideal 3 leaf stage of corn on June 5th.
Weeds were allowed to continue to grow in this second shot for an extra week until being sprayed on June 12th at the 5 leaf stage of the crop.Even though you'd tend to visually think the crop looks just as good, previous weed control timing studies have shown that there will be anywhere from .5 to 3.3 bu/acre/day yield loss due to the additional week of weed competition.
Weeds in this third shot were not controlled until June 19th when the corn was sprayed with glyphosate at the 7 leaf stage.As you can see leaving weeds to compete with the corn for this length of time has really hurt the crops ability to perform.Though the weeds have been killed and come harvest the grower will have a clean weed free field he will unknowingly have suffered some serious yield loss.
This last shot goes one step further to show the magnitude of impact uncontrolled weeds can have on the crop if spraying is delayed until the 9 leaf stage of growth or in this case June 26th.This is 3 weeks later than the ideal 3 leaf stage that was sprayed on June 5th.Though this is much longer than what most growers would ever leave weeds to compete with a crop it still goes to show just how much weed competition can hurt a crops performance.The take home message here is that for growers to maximize the yield performance of the hybrids they grow they need to keep their crop weed free from the Critical 3 -8 leaf stage in order to maximize yield.

Growers have found their No-til soybeans this year growing slower and staying yellower longer than normal as compared to their conventionally tilled soybeans.The fieldshot above shows
exactly what many growers have been experiencing.Part of this can be explained by the wetter and cooler spring that we've experienced.The extra 4-5 ton per acre of corn residue from last years bumper corn crop has not helped matters as it is contributing to keeping soils much more moist and cool.Soil bacterial populations are also tying up N as they break down the extra Carbon that has been added to the soil from last years bumper yields.The C/N ratio of corn stover is roughly 60:1 and the soil microbes job is to keep the soils C:N ratio at 10:1.The unfortunate part of this is that to break down this extra carbon load the soil micobes are tying up in their bodies most of the mineralized N that is in the soil.Though the soybean plant in the early part of its life depends on a bunch of this same mineralized N to keep it green and growing it is experiencing some serious competition from the soil microbes for N thereby leaving the soybean crop short of its needs and looking much yellower than normal.Because soil N mineralization has been very slow this year the plant is having a difficult time coming up with sufficient N to stay a healthy green until its nodules are formed.Once nodule formation occurs and kicks in gear the plant will be able to produce all of its own Nitrogen needs and turn a deep dark green.It takes roughly 8 lbs of N to produce 1 bu of soybeans.It remains to be determined whether an additional 30-40 pounds of N this year would have helped soybeans overcome this early N deficient period and produce more beans come harvest.There are a few locations that have tried broadcasting an additional 30-40 lb of N to their crop to see if this will have any beneficial result.Though this is not something that is normally recomended we will have to wait and see if under the circumstances of 2009 it has any value.
Conventionally tilled soybeans like those shown above have had the advantage of a slightly warmer seedbed this spring.This has helped the crop in two ways.First the warmer soil temperatures have allowed bacterial populations to mineralize N at a faster rate which has helped make the crop greener.Also the warmer soil tempeatures have helped improve the speed of Nodule formation so the plant can begin fixing its own N sooner.
We wouldn't normally expect to see No-til soybeans like those shown here staying dramatically yellower than conventionally tilled soybeans for such a long period of time.A factor that could be contributing to their extended yellowness is their slower growth rate.If soybeans are sprayed with Glyphosate,the Glyphosate/Enzyme complex moves to the plants meristematic tissue.With slower growth this higher concentration of Glyphosate-enzyme complex will cause plants to yellow flash.The only resolve to this dilemma is to hope that we receive some Warmer 80*F+ temperatures to move crop growth along.

In a wet cool year like 2009 slugs have been a menacing problem for many a corn grower.Generally speaking slugs would not normally be bothering 7 true leaf corn like that shown in these photos taken on July 7th around 7:30 PM in the evening.However with heavy residues to hide in and lots of cloud cover they have continued to be a greater concern for a longer period this year.Double click on the photos and you'll gain a greater appreciation as to how much leaf leaf tissue that they have already consumed.
Though this large 7 true leaf corn should survive this slug invasion the smaller 5 true leaf corn shown below may not be as fortunate.
The amount of leaf tissue consumed on these smaller plants is considerably curtailing their growth.
There are many plants that have suffered so much leaf defoliation that they have already died.
This field located just south of Mt Brydges along the 402 was planted in wheat residue.Though trash whippers were used to clear the wheat residue from the corn row the cooler moist soil and the wheat residue itself has served to provide a haven for slugs.There is no proven solution to control slugs.Though some growers have sprayed a 28% N solution near dusk results have been mixed as to its benefit.

It can never be stated enough how important it is that growers know exactly what traits and technologies they've purchased and what hybrids they should plant in each field.In the case of the grower above he had been planting glyphosate resistant corn when he moved to this field and filled up his planter with a non glyphosate resistant hybrid.As you can see when he sprayed the field in the second week of June with Glyphosate the non - glyphosate resistant corn was killed off. The small corn shown in these shots is now the new June 15th replant corn. Every year someone somewhere makes a costly mistake like this.This is exactly why EXPLICIT FIELD PLANS of what hybrids a grower should plant in each field should be well laid out on paper ahead of the planting season.