Warm Winter Effect On Crops Depends On Planting Dates

While the near-record warm winter Ohio has experienced this year will cause some insects to appear earlier than normal, whether or not the bugs will impact field crops negatively depends more on the weather in spring, the variety of insect, and how early or late farmers decide to plant this year, an Ohio State University Extension entomologist said.

Insects such as the bean leaf beetle, which damages soybeans, the corn flea beetle, which targets corn, and the alfalfa weevil will likely be seen earlier than normal this year, said Ron Hammond, who also has an appointment with the Ohio Agricultural Research and Development Center.

The reason?

This winter is the warmest winter experienced nationwide since 2000 and the fourth-warmest winter on record, according to the National Oceanic and Atmospheric Administration. This was caused because the jet stream, which divides the cold air to the north from the warm air to the south, settled at a much higher latitude this year, the federal agency said.

The warmer weather will cause insects to come out earlier to feed and become more active in the months before spring, Hammond said.

In addition, many insects migrate from southern areas, such as black cutworm, true armyworm and potato leafhopper, he said, noting that their development is affected by weather conditions farther south. Whether they migrate earlier or not into Ohio will depend on the weather conditions later this spring, he said.

But the impact these bugs can have on field crops depends more on the stage of crop development and growth, Hammond said.

“If insects arrive in fields early but no crop is even planted, this could lead to greater mortality if they cannot find alternative hosts,” he said. “However, if the insect arrives or begins feeding earlier when crops are smaller in size, a greater potential for injury exists.”

However, corn flea beetles in particular, and their ability to vector Stewart’s bacterial wilt, is of concern this year because of the warmer winter temperatures, Hammond said. In fact, more corn flea beetles are expected this year, significantly increasing the potential for Stewart’s bacterial wilt.

But farmers can mitigate the damage if they scout their fields earlier and with more tenacity, he said.

“We recommend that growers scout, scout, scout,” Hammond said. “Growers need to be out in their fields to be aware of the insects they’re dealing with and pay more attention this year, especially in the crop rows, because more insects may be waiting for crops to come out of the ground.”

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