White mushy larvae known as grubs are taking over Lincoln Square neighborhood parks just as warmer weather sets in — again.
The Chicago Park District discovered a grub infestation in Winnemac and Welles parks while evaluating fields for the season, Chicago Park District said in a March 9 letter to stakeholders.
Around mid-April, a landscape contractor will treat the park grubs and re-seed the grounds with fields closing for eight to 10 weeks after that as the grass grows again, Park District said in the letter.
They aim to re-open the parks’ fields and baseball diamonds on June 1 in Winnemac and July 1 in Welles, and are looking for alternative sites for the youth baseball leagues and CPS High School Sports to play, the district said.
But sports games are likely to be moved elsewhere for much of the spring season, frustrating the parents of over 2,000 kids registered in baseball and softball leagues at Welles Park Parent Association, a volunteer organization for youth baseball and softball.
“There’s probably just some disappointment, hey this is what I thought it would be and now it’s not,” said Joseph Negussi, WPPA president, who acknowledged that the Chicago Park District has been a “great” partner to work with.
Some are upset because the notice came just as the league was about to start its spring season mid-April. Now they may have to travel further to drop their kids off for games at nearby replacement parks, which haven’t been determined yet.
“No one’s happy about it, of course, but we’re gonna make the best of it,” Negussi said.
Grub infestations aren’t new to the 15-acre Welles Park. They were most recently back in 2023, recalls Negussi, who had hoped that after the treatment round, they wouldn’t return.
“It’s happening again, three years later,” he said. “We just want to make sure that it doesn’t happen again.”
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A grub on wet pavement at Chicago’s Welles Park in 2021. (John J. Kim/Chicago Tribune)
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A grub on wet pavement at Chicago’s Welles Park in 2021. (John J. Kim/Chicago Tribune)
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Grubs were also confirmed in some areas of Humboldt and Williams Park, the Chicago Park District told the Tribune.
Located between Lincoln and Montrose Avenue, Welles Park offers fields for baseball, football, softball and other sports. Winnemac, located at 5100 N. Leavitt St, is part of a school-park campus program and offers youth programs like basketball and summer day camp, according to the Park website.
Grubs are C-shaped, white beetle larvae that grow underground during the winter, and like an unwelcome flower, sprout during spring and summer seasons. The most common species in Chicago are the Japanese and Green June Beetle, said Christopher Dietrich, an entomologist at the Illinois Natural History Survey.
Grubs themselves are usually not an issue for homeowners with grassy lawns, but the holes that skunks and raccoons dig up to eat the larvae, can turn lawns into “mine fields,” said Rebecca Fyffe, director of research at Landmark Pest Management.
“Raccoons and skunks are digging holes next to each other until it’s just little holes and there’s no lawn left,” said Fyffe about the grub feasts of small mammals that “can turn a beautiful lawn into a big mud patch.”
Fyffe said she gets about three to five calls each day from June to October from people concerned about the holes in their lawn, especially green and well-irrigated lawns, in the Chicago metro area. For parks, that means the five-inch-deep holes and mud can interfere with sports activities.
But grubs are also important for the eco-system, helping sustain bats — crucial to controlling insect populations — in the area who feed off the mature larvae also known as June bugs, said Fyffe.
“I can’t stress how important these grubs are as part of a healthy ecosystem,” Fyffe said.
Since grubs are not considered a structural pest, owners who want them gone can spray an insecticide such as Trichlorfon, or hire a landscape contractor to assess.
Experts say there’s no research to suggest grubs are becoming more common, but Dietrich believes recent heavy rain might make them more visible to the unlucky park-goer, who may see them emerge. Similarly, recent droughts may cause them to lay more eggs in healthy-looking lawns instead of in natural vegetation.
Warmer temperatures due to climate change might be impacting grubs, said Fyffe, who is seeing more uncommon insects like black widow spiders in Chicago than in past years. But so far, grub calls remain consistent with prior years.
