What Extra-Long Silks Mean for Pollination

Extra Long Corn Silks ( RL (Bob) Nelson, Purdue University )

Certain areas of the country might be seeing extra-long silks on corn. This leaves many farmers with questions about what that means and if it will be a net positive or negative on pollination and overall yield.

When silks first emerge, they grow anywhere from 1” to 2” each day, and slow due to aging or inhibition caused by captured pollen, according to Bob Nelson of Purdue Extension in a recent post. Inhibition of silk elongation typically occurs within 12 hours of pollination.

However, if pollen never reaches the silk it will keep growing for up to nine days after it first emerges—which could lead to extra-long silks. This is a drought-defense system and often gives silks more time to capture pollen, which could mean the crop is more successful at pollinating.

While corn hybrids used to begin pollen shed before silk emergence, better genetics have allowed silks to emerge two to four days before pollen shed begins. Thus, giving the plant more time to catch pollinate, Nelson explains.

In some cases, when silks get too long you could see a downside.

“Kernel set near the base of the cob may fail it the initial emerged silks deteriorate enough prior to pollen shed that they become non-receptive,” Nelson says. “Kernel set near the butt end of the cob may also fail if later-emerging silks from higher up on the ear ‘shade’ or otherwise obstruct the initial emerged silks from capturing pollen.

“Because this phenomenon can result in poor kernel set, and lower grain yield, it may behoove you to check fields soon for the success of pollination and kernel set,” he adds.

Checking pollination is easy. Strip the husks and give the ear a good shake, the silks that fall were successfully pollinated, those still holding on weren’t. You can also examine the kernels to see it they’re starting to blister, the ones that look empty weren’t pollinated.