DROOPY EARS IN CORN R.L. (Bob) Nielsen Agronomy Dept. Purdue Univ. Ears of com normally re main erect until sometime after physiological maturity has occurred (black layer de velopment), after which the ear shanks eventually collapse and the ears decline or “droop” down. This year, com field connoisseurs have report ed droopy ears in fields before they reached physiological maturity. Droopy ears are cute on certain breeds of dogs, but Excellent quality seed that exceeds: • 95% warm germ • 85% cold germ • 97% pure • We treat our seed with the most effective seed treatments in the industry. • We continually review the newest developments in seed treatment and make changes as improved treatments become available. • We sell only well-graded seed. Even in plateless planters there is a yield reduction when you use un-graded or plateless seed. The best, most appropriate genetics for your farm. Professional, knowledgeable, and well-informed representatives to help you understand your choices. Excellent replant policy 2. 3. • Quick Service • Agronomic consultation • Reasonably priced replant seed Courteous seed delivery, on time, protected from weather. Honest and fair treatment with the customer’s best interest our priority. The right to return any undamaged seed prior to May 31 for full credit. Bird Hybrids/Keystone Group Family owned, located in Pennsylvania “We raise and use what we sell!” TALK NEWS UPDATE lIA CORN GROWERS ASSOC., INC. droopy ears on com plants prior to physiological maturity are a signal that grain fill has slowed or halted. Premature ear declination (the fancy term for this problem) results in premature black layer for mation, lightweight grain, and ultimately lower grain yields per acre. What Causes Droopy Ears? The few times over the years that I have observed this symptom, severe drought stress has been a common de nominator. Similar instances of premature ear declination occurred in areas of drought HYBIRDS 'STOMER BILL OF Rl RR 1 BOX 81A New Columbia, PA 17856 1-888-825-5088 (Local: 570-538-1170) teystone Grou Committed to Excellence in the Field! stress in 1991 and 1995. Under severe drought condi tions, but where a sizable ear nonetheless exists, a reduction in the turgidity of the ear shank occurs and the weight of the developing causes the ear shank to collapse. In some instances, collapsed ear shanks can also result from extensive tunneling by European com borer larvae. Such tunneling weakens the ear shank, allowing it to col lapse, and can ultimately also cause ear droppage from the plant. Impact on Yield? Remember that the ear shank is the final “pipeline” for the flow of photosynthates into the developing ear. An ear shank that collapses prior to physiological maturity will greatly restrict, if not totally prevent, the completion of grain fill for that ear, and will likely cause premature black layer development in the grain. If the droopy ears you’ve looked at have not black layered yet, they will soon. Lancaster Farming, Saturday, October 19, 2002, Corn Talk-Ell (DdDIH IPMJK MIWO The timing of the onset of droopy ears determines the magnitude of the expected yield loss. If grain fill were to tally shut down at the full dent stage of grain develop ment (milk line barely visible at dent of kernels), the yield loss would be as much as 40 percent. If grain fill were to tally shut down at the late dent stage of grain develop ment (milk line halfway be tween dent and tip), yield losses for the affected ears would equal about 12 percent. Multiplying the percentage of affected ears in a field by the estimated yield loss per ear will give you an estimate of whole field loss. For exam ple, if 10 percent of the field contained plants whose ears drooped prematurely at the late dent stage, whole field loss would be estimated at 1.2 percent (10 percent of the ears multiplied by 12 percent yield loss per ear). Don’t forget this and other timely information about com can be viewed at the Chat ’n Chew Cafe on the World Wide Web at http:// www.kingcorn.org/cafe. For other information about corn, take a look at the Com Grow ers’ Guidebook on the World Wide Web at http:// www.kingcom.org/.
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