Dear Clint,
First, welcome to more than 100 new subscribers from the Farm Progress Show last week in Decatur, IL. We hope you find out weekly agronomic news resourceful and enlightening.
This week we discuss late season weather extremes, stalk rots and top dieback in corn and soybeans.
As soon as the plot data starts rolling in, be sure and visit our harvest results web page. |
Scout now for Stalk Rots
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 During the grain filling period, developing kernels become a
significant photosynthetic "sink" for the products of photosynthesis
and respiration.
Corn plants
prioritize the movement of these photosynthates to the kernels, even at
the expense of not maintaining cellular health of stalk, leaf, and root
tissues.
The primary effect of severe stress on a corn plant
(drought, heat, nutrient deficiency, leaf diseases, insect damage, hail
damage, consecutive days of cloudy weather) is a reduction in
photosynthetic rates. If photosynthetic capacity decreases
significantly during grain fill, plants often respond by remobilizing
stored carbohydrates from stalk and leaf tissues to supply the intense
physiological demand by the developing grain on the ears. In addition
to physically weakening the stalk of plants, remobilization of stored
carbohydrates and/or the consequent lower cellular maintenance of root
and stalk tissues increases the susceptibility of the plant to root and
stalk rots.
Reports have already begun to trickle in from
several areas of Indiana about weak plants with varying degrees of root
and stalk rot development. Fields at higher risk for weakened stalks
and stalk rot development will be those where plants have managed to
set fairly decent ears but have experienced severe stress during grain
fill (primarily drought + high temperatures in 2007). Growers should
monitor stressed fields the remainder of this month and into early
September for compromised stalk strength or the development of severe
stalk rots and adjust their harvest schedules accordingly to harvest
these fields early in the season before that one big storm brings the
crop to its knees.
SOURCE: Bob Nielsen |
I have received a number of calls regarding the premature death of
corn beginning at the top with leaves dying near the top of the corn
plant as well as leaf death near the base of the plant while green
leaves are still evident in the middle of the stalk near the ear. 
