ISU experts are not certain what effect, if any, the warm winter will have on spring and summer insect populations throughout the state.

There is a widespread feeling among both farmers and other Iowans that the winter has a huge effect on the following year’s insect population, said Ken Holscher, associate professor of entomology. The spring weather may have more of an influence on insects than the extent of the winter.

“The honest answer is we don’t know,” Holscher said.

Usually, insects will crawl into cracks and crevices of buildings to lay eggs in the spring and then die when the weather gets colder. However, the long fall and mild winter may have allowed some insects to emerge earlier than normal.

But Holscher said spring is a better indication of whether there will be more bugs than usual.

“Most people assume if you have a real mild winter, you will be inundated by insects the following spring and summer and that’s not necessarily true,” Holscher said. “I think the more critical time is in the spring.”

The warm weather during this past mild winter will affect different insects in different ways, said Richard Pope, extension program specialist in entomology.

“For some insects, it’s going to be a boon that we had the warm weather. For others, it will actually be a detriment,” Pope said. “There’s some insects that we’re anticipating more problems from and some insects that we are actually expecting less from.”

One insect Pope said both farmers and homeowners may have increased trouble with this planting season is the bean leaf beetle, which looks like a ladybug but has six square dots on its back. Pope said he anticipates the pest “did not have very high mortality relative to other years.”

“We’ve seen increased numbers of these bean leaf

beetles over the past five or six years,” Pope said. “At the same time, we’ve had a series of rather mild winters.”

Pope said the bean leaf beetle causes problems by feeding on young beans both in soybean fields and gardens. The beetle can also be a carrier of a viral disease that can decrease soybean yield as well as decrease the value of infected soybeans.

Another insect expected to have increased populations due partly to the warmer winter weather is the lady beetle, more commonly known as the ladybug. Pope said while ladybugs bother many homeowners during the winter and early spring, they can become a positive asset when they leave homes in the late spring and early summer.

“It’s irritating to people when ladybugs seem to come crawling out of the woodwork and get in the way,” Pope said. “However, once they get into the field and get into the yard, they are a strongly beneficial insect because they are attacking some of the other insect pests we have.”

The gentle winter seems to have aided farmers with another problematic pest – the European corn borer. Pope said the European corn borer is “probably our number two economic pest of corn.”

Pope said early surveys are showing “almost record percentages of winter larvae” of the borer are infected with a usually fatal fungal disease.

“If they’re infected with the disease, it’s pretty likely they will not survive,” Pope said. “That’s a good thing. It’s one way we were benefited by the warm weather because it may have encouraged the disease to come on.”

Both Pope and Holscher said the population of many homeowners’ No. 1 pest – mosquitoes – will not really be affected by the winter weather. Pope said the rainfall pattern in upcoming months will be key.

“We’ll have mosquitoes,” Pope said. “When we have the problem years where we have huge populations of mosquitoes, it again is tied to the weather and the pattern of rainfall that we get.”

Another pest, identified just two years ago, may also pose a problem to farmers this year. The soybean aphid reproduces often, and during crop season can go through many life cycles.

Since many spray treatments are required to keep this bug at bay, the soybean aphid can be a real pest to farmers.

Both experts agree that while the warm winter may have allowed the survival of more insects, the weather patterns during the rest of the year will really dictate whether certain insects thrive or fail.

“I don’t get too excited over wintertime conditions,” Holscher said. “I wait to see what Mother Nature will throw at us. That will dictate what we have for the rest of the year.”

– The Associated Press contributed to this story.