Mark VanGessel, Extension Weed Specialist; mjv@udel.edu
Buggy-whipping in corn is a common sight early in the growing season and later under certain environmental conditions. The cause of buggy whipping is the abnormal formation of waxy leaf layers causing leaves to unfurl improperly. Agrichemicals and environment can cause this. The chloroacetamides (Dual, Harness, Surpass, Topnotch, Outlook, etc.) can all cause this problem. Injury from these products occurs either before the corn emerges or very soon after emergence. Postemergence herbicides such as Banvel, Clarity, Status, or 2,4-D in the whorl can cause buggy-whipping.
There is a phenomenon called “accelerated growth syndrome” that Bob Nielson at Purdue University identified as early as 1995, if not earlier. Basically it is unusual twisted growth where the affected plants are tightly twisted, often bent over severely and do not unfurl on a timely basis. Young leaves deep in the whorl continue to grow rapidly, but are unable to emerge from the twisted upper leaves. The growth stage where this seems to occur is around 5 to 6 visible leaf collars. After the whorls unroll, you may see “yellow tops” across the field. The younger leaves that had been trapped inside the twisted upper leaves are yellow because they had been shaded for quite some time. After a day or two the plants will green up and the problem will not be visible. Yield effects will be minimal, if any. This problem often occurs when the field has plenty of nutrients and moisture, but growing conditions are less than favorable followed by a sudden return to optimum growing conditions. I have seen this occurring in some of my plots this year. It appears some hybrids are more prone to developing it than others.