Mayflies a dark spot on GM's launch of big SUVs

Bug stains marring the launch of General Motors' most profitable SUVs?

Add mayfly mayhem to the list of auto industry problems in 2020.

GM believes the insects, also known as fishflies, are responsible for stubborn black residue dotting more than 2,600 Chevrolet Tahoes and GMC Yukons that were built in Arlington, Texas, and waiting to be shipped to dealerships.

The mess has delayed shipments of the redesigned 2021 SUVs to dealerships already coping with tight inventory levels. Some stores have spent hours working to carefully remove the substance without harming the paint.

One Tahoe that arrived at Pete Eischen Chevrolet in Fairview, Okla., last week — three months after it was built — has been hit so hard that the hood has to be painted, Sales Associate George Eischen said. The chrome accents, painted panels, windows and wheels also were spattered.

"We were told all would be cleaned before delivery. We waited three months for nothing," he said.

Behind full-size pickups, large SUVs are GM's most profitable segment and offer the kind of bottom-line boost that the automaker and many dealers are desperate for during a difficult year. GM is addressing the problem before sending most of the vehicles to dealerships and expects to have all of them cleaned by mid-September. GM said fewer than 100 affected SUVs made it to dealerships before being cleaned.

"Plant personnel are rapidly cleaning vehicles so that they arrive to our dealers and customers in flawless condition," a spokeswoman said.

The SUVs were being stored near a lake after leaving the Arlington plant. High populations of mayflies are common around lakes, said Molly Keck, an entomologist and specialist with the Integrated Pest Management Program at Texas A&M AgriLife in San Antonio. The emergence of a big population "may not happen every single year, but it definitely happens," she said.
The insects can emerge from the water any time of the year, she said, and typically fly toward a light to mate before returning to the water. "It just really depends on water, and if they have a [water] source where they've been able to lay their eggs."

Although GM is blaming the residue on mayflies, it remains somewhat of a mystery.

Mayflies "don't really make a stain," Keck said. "When they emerge from the lake, they're not feeding. So there's nothing in their gut for them to be able to excrete out."

The automaker sent Chevy and GMC dealers a bulletin this month explaining that there may have been insect residue, a grease substance or spots on the paint when new Tahoes and Yukons were delivered.

It instructed dealerships that received affected vehicles to use a bug remover, wash with a brushless car-wash system or power washer, apply polish with a foam pad and inspect the paint under high-intensity fluorescent lighting. GM allotted dealerships up to 2.5 hours of warranty repair time per vehicle, according to the bulletin, a copy of which was obtained by Automotive News.

Pete Eischen Chevrolet received another affected Tahoe about 10 days before the latest arrival and sent it to an independent body shop. That vehicle had been sold to a customer before delivery but was still in the shop last week, George Eischen said.

The dealership is eager for every Tahoe it can get because inventory has been low since the spring, when the coronavirus pandemic forced GM to halt production across North America for eight weeks.

"These are our profit item right now," he said, amid even tighter supplies of the store's usual top seller, the Silverado 1500 Crew Cab. "These desperately needed units were another 2020 failure for a struggling Oklahoma rural dealer who needed them for the bottom line."