Obviously, this is not a weed. Perhaps instead of putting it under the "Weed of the Week," I should give it a separate page, the "Menace of the Month” since it is primarily a June infestation. ​

​​Several people have asked me about some irritating, ubiquitous, destructive bugs (I’m trying to express my dislike of them without compromising my upbringing) so I thought I’d discuss them instead of a weed this time. In my garden the main offender right now is the rose chafer beetle, I’ve heard some people call them potato bugs, but they aren’t. I know because I also have potato bugs. Unlike the rose chafer beetles, the potato bug flies rather quickly and purposefully. We used to call the rose chafer beetles and the related Japanese beetles “clumsy bugs” because they never seem to be in control of their motions. Every landing seems to be a crash landing.

​Rose Chafer Beetles prefer sandy soil…but do not limit themselves to sandy areas. They are called rose chafer beetles, but they aren’t any more particular about their food than the soil. They really like grapes, strawberries and other fruit leaves. These beetles “skeletonize” the leaves — eating the leaf tissue between the veins — as oppose to just chomping the whole leaf down.

Caught in the act

​Beginning in June the bugs emerge from the soil where they have lived as a larva and begin eating almost everything in sight. Some plants seem almost buried in the insects.

​There is a ray of hope. The damage usually is only cosmetic. They may make plants look ghastly, but plants generally recover once the infestation ends. So, here’s some good news: the beetles die out around the end of June. The bad news is that they lay eggs in the soil before they die. The grubs hatch and burrow deeper into the soil to eat and rest until the next spring when they will emerge to decimate everything in their path. The only good thing I can say about them is that they don’t eat the roots of the grass so at least the lawn is spared.

Suggested methods of controlling the rose chafer beetles include hand picking them, but I think a person could potentially damage their carpal tunnel nerve if they tried to pick all the beetles. Another suggestion is to have a Dust Buster or similar hand vacuum that is dedicated to bug removal (it will get gross inside). Vacuum them off the plants and dump them into soapy water. Even kids wouldn’t mind doing that.

​Common garden insecticides such as Sevin and malathion are also suggested but they need to be reapplied every 10-14 days or after a heavy rain. A less intimidating chemical would be an insecticidal soap or Neem oil. Systemic insecticides, like those found in rose care products, will work but the beetle has to take a bite of the plant before it is poisoned, so some damage continues to occur and I wouldn’t suggest using these on edible plants like grapes or strawberries.

Some people use finely netted row covers like cheesecloth, but if you are depending on pollinators for plants such as grapes, you don’t want to shut them out with the beetles. Some people use traps, but the scent has been known to lure beetles from other people's property. Also, because the beetles are so erratic in their flying, the traps should be at least 50 feet away from the plants you are trying to protect or they will very possibly miss the trap and land on the plant.​One reason rose chafer beetles are so abundant is that no one eats them. They contain a toxin that can sicken or kill birds and small animals. Fortunately, the chickens seem to know this. While they seem to instinctively jump at any moving thing without thinking, when it comes to the rose chafer beetles they don’t even notice them.

​According to the experts, the rose chafer invasion is over by the end of June and then Japanese Beetle infestations starts. As awful as that sounds, in my neighborhood the Japanese beetles are already hanging out with the rose chafer beetles. They don't wait until July. They are all clumsy together.

​Unlike the rose chafer beetles, Japanese beetle grubs do cause damage to the grass by eating the roots. One way to attack them is by adding HB nematodes to the lawn. These things sound magical. Nematodes are a type of worm. It’s been estimated that there are about a million different species of nematodes — some beneficial, some nasty. The specific kind needed for Japanese beetle grubs is the HB (Heterorhabditis bacteriophora) nematode which is also effective on the rose chafer beetle. The point is to give the grubs worms. The nematodes seek out the grubs and enter their bodies. Then they excrete a bacteria which converts the grub into food for the nematode. It’s sort of like the nematode digests the grub from the inside and then eats it. When the grub dies increased numbers of nematodes leaves the dead grub and start searching for a new one to devour. This sounds like the inspiration for an alien horror movie. Fortunately, beneficial nematodes only attack soil dwelling insects so plants, birds, earthworms and people are safe.

​Another method of attacking the grubs is a type of bacteria that causes milky spore disease. The females lay eggs in late July or early August. The eggs hatch soon afterward and begin to feast on the grass. As the weather gets cooler the grubs go deeper into the soil so the best time to get them is in August, after they hatch and before the cool weather drives them deep into the soil. When the grubs are feeding they eat the spores from the bacteria which reproduce in the grub and eventually kills them. When the grub dies the increased spores go back into the soil for the next grub to eat. Like the nematodes, milky spore in the soil is not harmful to beneficial insects, birds, bees, pets or people. However, in Minnesota they are killed out by harsh winters and need to be added to the soil every year.

Japanese beetle grub.
The chickens love these things!

​While, rose chafers seem to tend toward flowers and fruit leaves, Colorado potato bugs love nightshade plants, like potatoes, obviously. However, in my garden I’ve discovered they definitely prefer ground cherries to potatoes. They also like tomatoes, tomatillos and even peppers, but the ground cherries get the brunt of their attack.

​Unlike the chafers, the Colorado potato beetle does not skeletonize the leaves. They just chomp them like a caterpillar. ​

These are less “in your face” than the clumsy varieties, but prehaps more destructive. They are very prolific; one female can lay as many as 800 eggs usually depositing them in batches of about 30 on the underside of leaves. These eggs hatch into disgusting slimy larva. Few things in nature gross me out, the potato bug larva is one of them. They are fat, slimy and squishy, gathered in bunches on the leaves and stems.

Larva on what used to be a ground cherry plant

​With each female laying up to 800 eggs, there is no shortage of these bugs. This is especially tragic because they also have the ability to rapidly develop a resistance to chemicals and have developed resistance to all the major insecticide classes. This makes chemical control rather unsuccessful. Since there are so many of them, even natural predators have a hard time making a dent in the population.

​This bug is such a serious threat to those who rely on potato crops that it has gotten the reputation of being evil. During the Cold War areas of the USSR claimed the beetle was a CIA plot to destroy their agriculture. A children’s book published in Czechoslovakia in 1950, On the Evil Potato-Eating Beetle, presented the Colorado beetle to children as an enemy from the West to destroy communist agriculture. Children were instructed to fight this evil and were even released from school to gather the bugs and drown them in gasoline or alcohol.

​And the distasteful reputation of the potato bug continues. As recently as the 2014 unrest in Ukraine the pro-Russian separatist were sometimes derogatorily called kolorady, the Ukrainian term for the Colorado beetle. The name began in reference to the black and gold Saint George's ribbons worn by the separatists.

The more I garden, the more I understand the farmers' frustration with insects. Sometimes it seems like a very unfair battle. When I'm in that sort of mood it a good time to remember, it’s a beautiful world, but it’s not perfect.