Boozy Beetle Wreaks Havoc on Lawn Mower

Editor’s Note: The following article appeared in Mike Merchant’s blog, “Insects in the City,” which can be found at insectsinthecity.blogspot.com. The blog offers readers news and commentary about the urban pest management industry and is excerpted here with permission of the author.

Every now and then I get a note about a pest so bizarre it’s kind of hard to believe. I recently received an email through one of our county offices from a citizen having problems with insects boring into his riding lawn mower gas tank. He knew it was an insect that made the perfectly round holes because they were still inside some of the holes, and he was able to carefully extract about 15 of them.

And this wasn’t the first time. His neighbor had a similar experience with his mower being damaged by the little pests the previous spring.

Being good at your job doesn’t mean that you know all the answers, but it does involve knowing where to go for the answers. In this case, I got lucky. I put out an inquiry about gas-sniffing beetles to entomology colleagues and immediately got several replies.

Some of my colleagues recalled a paper put out in 2011 by Chris Carlton and Victoria Bayless at the Louisiana State Arthropod Museum. They had published a scientific note describing cases where a small beetle had been found boring into plastic gas cans. The authors identified the beetle as a type of bark beetle called camphor shot borer (CSB), Cnestus mutilatus.

The finding must have impressed even my Louisiana colleagues because, as they reported in their paper, the can is now permanently stored at the Louisiana State insect museum (http://lsuinsects.org).

The CSB is yet another insect that’s not native to this country. It was first reported in the U.S. in 2004, and is now found throughout the Southeast from North Carolina to Texas. It normally feeds on a variety of hardwoods, but especially sweetgum. In Texas, it’s more likely to be found in the eastern part of the state.

One entomologist pointed out that these beetles are commonly attracted to his alcohol-baited traps used to collect other bark beetles. Since most gasoline these days contains alcohol, it makes sense that alcohol may be what’s attracting these little guys to lawn mowers.

Aside from patching tanks with duct tape, how can we use what we know about this insect to prevent it from ruining lawn mowers and perhaps causing fiery mayhem from Charlotte to Houston? A glance at the collection data stored on BugGuide suggests that this beetle is active primarily in the spring (March to June). So, protecting gasoline containers in the spring is particularly important. Storing gas canisters and mowers in enclosed sheds or under some type of tarpaulin may be helpful, especially in the spring. Keeping the outside of the plastic fuel canisters free of spilled gas also might help.

Being good at your job doesn‘t mean that you know all the answers, but it does involve knowing where to go for the answers. In this case, I got lucky. I put out an inquiry about gas-sniffing beetles to entomology colleagues and immediately got several replies.

The last solution might involve finding gasoline that doesn’t contain alcohol. But that might be harder than building a new shed for the mower.

The author is an entomology specialist for Texas AgriLife Extension. Readers can contact him via email at mmerchant@giemedia.com.