A number of stress factors or injuries can interfere with corn pollination. Once corn ovules (developing kernels) start to swell, the success of pollination easily can be determined.
Prior to that time period, here is an easy way to determine the success of pollination:
The time period for this test is between pollen shed and blister formation.
Select the corn ear you would like to check. Carefully remove the husks. With the tip of the ear pointing down, shake the ear. Silks will fall from ovules that have been successfully fertilized.
Silks that remain attached indicate ovules that have not been fertilized (pollinated).
Pollination of this ear of corn was poor, as indicated by silks that didn't drop free of the ear when the ear was shaken.
Tip: With a sharp knife, make a longitudinal cut the length of the corn ear. You may also carefully cut through husks at the base of the ear. This will make the husks easier to remove. With practice, you will be able to determine how deep to make the cuts.
This method of checking pollination only helps determine if the pollination process is successful. According to Dr. Bob Nielsen at Purdue University, severe wilting of corn in the two weeks prior to silking can reduce yield 3 to 4 percent per day. During the silking and pollen shed period, Nielsen indicates that severe stress can reduce yield 8 percent per day.
During the two weeks following silking and pollen shed, severe stress can reduce yield 6 percent for every day that the stress continues.
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Kevin Black is GROWMARK’s insect and plant disease technical manager. His e-mail address is kblack@growmark.com.