Recently I've seen the effects of cloudy skies and wet soil. I spent time in fields with saturated soils and noticed a continuous pattern, purple!
Areas that took on heavy rains through the final days of May are showing the purple leaves, commonly referred to as "purple corn." This has been a result of waterlogged soils where the fibrous root system in corn has been limited to growth.
Scout's Report 6/10: Minimal insect pest activity in fields so far
Fibrous roots are responsible for the uptake of nutrients like phosphorous, sulfur, manganese, and zinc. When these roots cannot find these nutrients, the plant will show the signs of nutrient deficiencies. Purple leaves indicate a lack of phosphorous in the plant which is commonly due to saturated soils where the roots cannot breathe.
Another common sign of nutrient deficiencies I have found in most fields is the distinct yellow striping between veins on a corn leaf. This indicates a similar issue, where the plant cannot take up manganese, zinc, or sulfur.
These corn plants are in the V3-V5 growth stage. With the crop being young, it will grow out of the discoloration with warmer conditions.
Ben Grimme, one of my supervisors, and I found some cases of rapid growth syndrome in some corn. This is a result of extended cloudy, cool periods before a time of warm temperatures and sunshine for corn around the V5 growth stage. We have only noticed this on a small portion of a field and in no continuous pattern.
The look of it may concern some growers, but they should be assured it will not decrease yield or impact plant health.
Recently I traveled to Marion to evaluate hail damage on corn and soybeans. Areas of the corn looked demolished from the road. I learned that as long as the growing point can make its way through the ragged leaves above it, that the plant will recover and still produce 95% of original yield potential.
Young corn can recover >>
Young corn has an amazing ability to recover from early season damage, but patience is required to allow damaged plants to demonstrate whether they will recover. Damaged but viable plants will normally show noticeable recovery from the whorl within five to seven days with favorable weather and moisture conditions. These plants were around the V4 growth stage, so the growing point was right at ground level and protected from the hail's direct impact.
The soybeans looked totally dead from first glance. We determined that the auxiliary buds were still intact and yield would not be affected. Both crops will not call for replant because of hail since they have the proper parts to continue life.
My insect traps did not show much moth flight. Rain over the previous weekend most likely killed the moths when their wings got wet. I found some black cutworm moths in north central Indiana, however they are of no concern to these farmers because the crop is beyond the growth stage that they will affect yield.
Look for my findings again next week!
Kettler is an intern with Beck's Hybrids, working with Beck's staff, primarily Ben Grimme, Kris Johnson and Denny Cobb. Cobb contributed to this story.