he
current
USDA corn per acre yield estimate for Indiana puts the Hoosier State
squarely in first place among the major corn producing states and is identical
to the final yield estimate of 147 bu/ac for the 2000 crop. What triggers this
fearmonger alert is the memory of last year’s near epidemic of stalk rots
that accompanied the high yields. While I’ve not heard of any significant
discoveries of stalk rot yet in this year’s crop, I nonetheless believe
folks should spend some time walking fields during the next several weeks to
confirm that the problem is not developing.
Conceptually, the potential for stalk rots to develop when yield potential is high is due to the fact that high yield potential requires a lot of output from the photosynthetic factory that we otherwise call a corn crop. If stress of any kind during the grain fill period severely limits the photosynthetic output, the corn plant is more likely to remobilize stored carbohydrates from the lower stalk reserves to the developing ears. When the carbohydrate concentration declines in the lower stalk and root tissues during grain filling, the plant becomes more susceptible to the development of root and stalk rots.
Last year’s stalk rot outbreak was the result of several plant stresses during grain fill including significant loss of healthy leaf tissue due to diseases and significant drought stress beginning in late July. By early August last year, stalk rot symptoms were evident in many fields and quickly became a major problem during the harvest period.
Fortunately, this year’s crop is generally healthier than last year’s crop. Soil moisture conditions, on average, are also more favorable at this moment. Indeed, few if any reports of stalk rot have come to my attention.
Nonetheless, if you know that certain fields or areas within fields have been under considerable stress during the past few weeks AND the yield potential of the field was heretofore pretty darn good, it would behoove you to spend some time walking those fields and inspecting the condition of the lower stalks. The inspection technique is simple: Squeeze the lower stalk. If it collapses easily, you’ve got trouble. If you cannot squeeze it easily, you’re probably okay.
For other
information about corn, take a look at the Corn Growers Guidebook on the World
Wide Web at http://www.kingcorn.org