Update from the Field: Twisted Sister
Posted by David Dyson, Agronomist on June 18, 2018
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As the corn growing season moves from cooler, spring-like weather to the heat of summer, it is not uncommon to see fields with scattered plants whose leaves appear twisted or wrapped. This phenomenon is known as rapid growth syndrome. It can occur when the corn plant transitions into the very rapid growth stage beginning at V5 and lasting through late vegetation, at V12. The rapidly-expanding plant leaves tend to remain rolled (Figure 1) in the whorl and fail to unfurl as the growing point pushes out new vegetative material. Hybrid differences can be seen in the field as well. While some genetics appear more prone to twisting, differences in relative maturity, rate of plant growth, and timing of temperature changes in the environment can all help to explain many of the visual differences between hybrids in a field.
Figure 1: Twisted corn plant caused by rapid growth syndrome. This picture was taken north of Kokomo, IN on 6/4/18.
The main cause for twisted whorls is an extreme increase in temperature, which stimulates rapid growth in the plant. I saw many acres affected by this syndrome after the last major heat wave. Over Memorial Day weekend a few weeks ago, we experienced daily high temperatures reaching over 90 degrees Fahrenheit in northern Indiana. Following a cooler, wet period, we are about to reach those same highs again. With this in mind, growers should be aware that rapid growth syndrome may appear.
In some fields with larger twisted plants or with very tight twisting, you will see yellow or white leaves (Figure 2). Leaves will become yellow or white within the wrapped plant due to lack of sunlight penetrating the layers of leaves within the twist (Figure 3). When they release from the whorl, the yellow or white color is present but quickly recovers with exposure to sunlight.
Figure 2: Leaves showing no pigment due to being deprived of sunlight while wrapped inside twisted leaves. This picture was taken north of Kokomo, IN on 6/4/18.
Figure 3: As you look across this field, you can pick out white “flag” leaves every now and then as they unroll. This picture was taken north of Kokomo, IN on 6/4/18.
You may notice bumps or blisters (Figure 4) on the twisted corn leaves that resemble Dicamba injury on soybean leaves. This symptom is not necessarily a chemical reaction. When the inside of the leaf grows faster than edge of the leaf, this can present as blisters.
Figure 4: The "blisters" on the leaf are caused by the interior growing faster than the edge of the leaf. This picture was taken north of Kokomo, IN on 6/4/18.
In conclusion, rapid growth syndrome tends to be a short-lived phenomenon that is obvious for several days before the leaves unfurl. Observations comparing twisted and non-twisted plants have not shown noticeable differences in yield. Typically, by tasseling, it is very difficult to pick out those plants that were twisted earlier in the season. If you are experiencing similar or other symptoms in your fields, contact your local representative at The Andersons for assistance in correctly diagnosing issues.
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Dave Dyson is a regional agronomist for The Andersons’ Farm Centers which are located throughout Ohio, Michigan, and Indiana. He is an Indiana native and grew up on a dairy farm in Miami County. A graduate of Purdue University with a degree in Crop & Soil Science, Dave has a deep knowledge of various agronomic topics and is committed to helping growers improve their crops. If you have any questions, Dave can be reached at david_dyson@andersonsinc.com.
