University of Missouri Extension
LAMAR, Mo. — Jill Scheidt, agronomy specialist with University of Missouri Extension,
scouted fields near Arcola in Dade County and near Verdella in Barton County on July 22.
Scheidt observed corn that was finished pollinating and either in the blister or milk stage.
To find out how well your corn pollinated, visit YouTube and search for Scheidt’s video, “How
to tell how well corn pollinated.” (Direct link at http://youtu.be/imbS9Z6vJvE).
“Once pollination has occurred, silks are no longer needed, and Japanese beetles are not a
threat,” said Scheidt.
Scheidt observed soybeans ranging from emerging to bloom stages.
“Japanese beetle populations are lowering and should not be of much concern,” said Scheidt.
Threshold levels for Japanese beetle in soybean are 30 percent defoliation before bloom and 20
percent defoliation during and after bloom.
Bill Wiebold, plant science professor at University of Missouri conducted a two-year study on
this issue. Using a seeding population of 150,000 seeds per acre and a maturity group three,
soybeans planted in mid-July yielded around 30 bushels per acre.
Over 30 years of data from University of Missouri weather stations suggests that the median
probability date for a killing freeze, of 28 degrees, begins Nov. 7.
“Soybean yield is protected from frost if the plants have reached physiological maturity. If a
killing frost occurs before this time, harvest will be difficult and soybeans are likely not to
change color,” said Scheidt.