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Sponsored: Pollination Stress Impacts Yield

Pollination often takes place over a week’s time or longer, and corn plants are most vulnerable to pollination stressors during the two weeks of pollen shed. Extreme heat and drought stress lead the list of factors that hinder effective pollination.

This is especially true when daytime temperatures exceed 95 F with low relative humidity and plants are experiencing drought stress during the critical pollination period. The greater the number of days the plants experience the described conditions, the greater the potential yield impact. In addition, temperatures above 100 F can seriously hinder and even kill pollination. 

Most weather-related pollinator stress is caused by hot temperatures combined with a lack of rainfall. However, damage resulting from hailstorms during the tasseling stage can be equally harmful, further reducing the pollen source.

“During pollen shed, without any cooling at night, farmers will see the most issues,” says Jason Welker, Mycogen commercial agronomist for western Nebraska. “Unfortunately, we can’t control Mother Nature, but understanding how conditions can impact pollination can help us to determine potential yield loss.”

While growers are powerless against the forces of Mother Nature, there are steps to take to mitigate the effects of both insect feeding damage and environmental conditions. For example, applying irrigation during drought stress can help.

Managing pest populations is one way corn growers can improve pollination potential. Feeding by corn rootworm beetles and Japanese beetles can damage cornsilks, potentially decreasing the silks available for pollination.

Drought or heat stress during pollination can also result in zipper ears, or ears with missing kernel rows. Ears affected by zippering have kernels that developed poorly or more slowly than other kernels or have ovules that aborted shortly after pollination. Also, scout for silk-feeding beetles during pollination, and treat when population thresholds are reached.

“Understanding how heat and other environmental factors impact yield can help growers plan,” Welker adds. “If you know you’re a in drought- or heat-stressed geography, consider lower populations, a full-flexed ear type and even a stress-tolerant hybrid.”

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