Bugs are appearing in our driveway at night. Most are almost dead. But they...

Asked May 8, 2015, 2:34 PM EDT

Bugs are appearing in our driveway at night. Most are almost dead. But they could awakening from hibernation. I have attached two photos of one. My questions are: 1) what is it? 2) are they harmful? 3) Do we need to be concerned.

Belmont County Ohio entomology

1 Response

Wow. These beetles are right on time.

You have a 'May' or 'June beetle'---which would fall into the beetle order (Coleoptera) and beetle family called Scarabaeidae. A common genus would be Phyllophaga---roughly translated, it means 'leaf feeding.' Your local Extension office would probably verify that genus and put a species name on it, too.

You are seeing the seasonal emergence of the adult stage of this insect. This will occur every year about this time---hence, the common name. The adult beetles have completed their development and have emerged to disperse around the countryside, find mates and reproduce. This particular species will probably be around for the next month or two, but you'll probably see more members of this family throughout the summer---some larger and some smaller than these. Many of these scarab beetles fly at night and are readily attracted to outdoor lights. Installing 'bug lights' outdoors might reduce some of the beetle traffic in your driveway, but maybe not much.

After mating, female beetles will lay several batches of eggs after digging down through your grassy lawn to a depth of a couple of inches, most likely. You may or may not see evidence of egg laying, but in the next few weeks, those eggs will hatch to produce a tiny 'white grub.'

'White grub' is the common name for the characteristic larval stage associated with the scarab beetles---all of them. When exposed to bright light, these chunky, multi-segmented white larvae curl into a characteristic defensive pose---a C-shape. They will have 3 pairs of segmented legs on the thorax and a well developed, dark reddish brown head capsule and chewing jaws. You will find these---or larvae of other species of scarab beetles---when you dig in the garden or dig up some turf.

Hatchling grubs will be tiny. As they feed on grass roots, they grow and molt several times over the summer and early fall. But as day lengths and soil temperatures decrease in fall, the middle-sized grubs---full of fat now---move deeper into the soil and become less active. Fat sustains them over the winter; their physiology changes such that they don't freeze despite how cold it might get. In the latter part of winter, the grubs become active again and dig back up into the root zones of the grasses. Their physiology shifts into high gear now; they grow larger yet and eat substantially more. Once they reach larval maturity, they molt into a transitional stage called the pupa which also occurs in the soil. This stage neither eats nor moves. After a few weeks, the adult emerges, digging an exit hole to the surface and taking flight. One year is a common length for a life cycle of these insects.

As for their effect---if you have a lawn with bald spots or browning patches, these could be due to the feeding damage of white grubs. In Ohio where you have rain and humidity, some turf problems could also be due to disease. Your Extension office and agents could help you determine which is what and appropriate measures for each.

Over the course of the summer, you will see other species of scarab beetles, too, most likely. If you haven't had a lawn before, you will learn more about them in the next few months than you ever thought possible.

However, May and June beetles can't hold a candle to another member of the scarab beetle clan---Japanese beetles. Their white grub larvae feed on roots of turf and other plants, but the adults fly during the day, feeding on foliage and often fruit and sometimes thin bark on a variety of landscape trees, shrubs, and ornamentals. Their adults are rather attractive with dark emerald green tones, but their appetites and potential destructiveness are legendary. Some years will be worse than others. You can get all of the info you need at your local Extension office. Or you can get a head start on this project 'on line.' Google 'white grubs,' 'turf insect control'---and especially 'Japanese beetle' and see what you're in for.

I attached 3 pictures for you. Phyllophaga is the adult stage of a scarab beetle---and is what I think you would have now. Popillia is the genus of Japanese beetles. What that grub looks like is basically what other members of the scarab beetles look like in that immature larval stage. All of them will be underground in the larval stage. The green June beetle in the pasture is basically the life cycle shown over the months---typical for the beetle family.

If you live in an apartment and have no landscape to care for, you'll still have flying beetles. If you do have a landscape, you'll be in for a crash course in landscape care and maintenance. There is no 'once and done' treatment for these insects; there are treatments for them involving various appropriately labeled insecticides. Rather than rushing down to the nursery or WalMart or some place and staring at products, not knowing which to pick for what, consult your local Cooperative Extension Service office to skip the confusion and get some facts. Before buying ANY product, READ THE LABEL to see if it fits your problem and you have the appropriate equipment and skills to apply it. READ THE LABEL again as you prepare to use the product, especially if it's 'been a while.'

If you don't find the phone number for your Cooperative Extension Service in your local telephone book (try county, state or government listings), go on-line and look for Cooperative Extension Service under the 'Ohio State University' web page. That web site will be a wealth of information for you on insects, mites, plant diseases, weeds, plant selection and care, etc etc etc.

Just FYI---where I am located, southern New Mexico---we have no established Japanese beetles. With our continuing drought (seems we're always in one), grassy lawns are not that popular or extensive here. We still have May and June beetles, but with our elevation---and possibly because we are in the 'Land of Manana,' our scarab beetles tend to appear more in June through September and usually mid-October. We really can't appreciate the scarab beetle problems that you have in Ohio and most of the Midwest.

Good luck with this project---and check out the Cooperative Extension Service.