North Stonington - Four years after the state banned the use of conventional pesticides on school fields, grubs have rendered Wheeler High School/Middle School ball fields unusable, school officials said.

The town has had students play on recreation fields and at Dodd Stadium - locations that are still allowed to use non-organic means to deter pests, according to North Stonington Superintendent Peter Nero.

Between 12 and 20 grubs might be living under a small area of grass in the North Stonington fields, Nero said. But the damage isn't from the grubs themselves - it is from the animals, like skunks, that seek them out as a food source and dig into the ground.

That's what caused Wheeler's fields to become pocketed with holes that could easily trip and injure athletes.

"This my 39th year in public education - I've never had to deal with grubs before," said Nero, who until recently worked in Rhode Island schools.

The state's pesticide ban took effect for day-care centers and schools with students in kindergarten through eighth grade in October 2007. This March, the state legislature voted to expand the ban to high schools, parks, playgrounds and municipal greens, but that will not take effect until January 2017.

A study of the grub population on the school fields was conducted by University of Connecticut specialists Steven Rackliffe and Jason Henderson, who determined that 98 percent of the grubs are a variety that is difficult to control using measures allowed by state law.

Grubs are the larval stage of certain types of beetles, said Rackliffe, and many fields in this area contain a species that can be controlled by parasitic nematodes, which are allowed on school fields. But North Stonington is infested primarily by European chafers, which are "a little bit tougher," said Rackliffe, who is an associate extension professor of turfgrass science at the University of Connecticut.

Although Rackliffe said he's not an expert on the chafers, he believes it is unusual for a population as large as the one at Wheeler to develop. He said they are more commonly found in small pockets among Japanese beetle grubs.

The European chafer "may be the most serious grub pest of home lawns and low-maintenance turf," according to the Michigan State University's Department of Turfgrass Science website, which recommends treating an infestation with insecticides.

Rackliffe said he and Henderson are "trying to provide (North Stonington) the best way to manage those fields within the state law." Right now, he said that appears to be constant overseeding and adding new grasses, increasing the density of the turf.

That method is costly, however, and not guaranteed to work.

This is the first year since 2007 that the grubs have created a problem for North Stonington. The use of effective pesticides until 2007 likely prevented problems, said Nero, who believes the effects are just beginning to wear off this year.

The fields were doing alright until a period of heavy rainfall this summer, which was when the grubs "really started to get active," Nero said.

To counter the grub population in accordance with state regulations, North Stonington public schools have allotted more than $30,000 to re-seed the fields. Nero, however, did not seem optimistic about the results of that method.

Preston Superintendent John Welch said his schools, especially Preston Plains Middle School, have encountered similar problems.

Over several years, there has been "growing deterioration" in the fields, he said. They are still playable "but it's really just a matter of time" until they reach a state as "extreme" as North Stonington's, continued Welch.

Overseeding, said Welch, "from our point of view isn't a solution. It's a band-aid."

He said the state should amend the law to allow for the use of pesticides at schools in certain circumstances. He also criticized what he sees as inconsistencies in the regulations: pesticides can, for instance, be used if insects invade the school cafeteria, but can never be used on the fields.

"We're just looking for some common sense here," he said. "We're not asking for a total removal of this ? but I think there has to be some kind of waiver system."

In a letter sent to State Rep. Diana Urban, D-North Stonington, in late October, First Selectman Nicholas Mullane took a tougher stance against the law.

"We will have to ship our students out of town for home games," wrote Mullane. "This Bill HAS TO BE reversed or modified."

He also cited a statement by the Connecticut Council of Small Towns that opposed the regulations, noting that many towns have had difficulty maintaining their fields and that "the use of an Integrated Pest Management Approach and an advisory board would be better."

The first selectman was not satisfied with Urban's reply - an email the following day that read, "Talking to environment comm chairs to see if we can add an emergency application. I walked the fields. It is bad!!"

Mullane wrote back that an "Emergency Waiver would be great but legislation still needs to be revised or repealed."

k.catalfamo@theday.com

Twitter: @kccatalfamo