Have you seen fancy green bugs flying around the yard? Japanese beetles are in the air, and boy are they hungry! Their favorite food? Adults will eat holes in flowers, leaves, and fruit. They feast on roses, raspberries, currants, grapes, peaches, apples, and many other plants.
And they can really eat. According to the United States Department of Agriculture, the Japanese beetle is the most widespread turf-grass pest in the United States. Efforts to control them in the larval and adult stages are estimated to cost more than $460 million a year. Losses from grubs alone have been estimated at $234 million annually, and $156 million to replace the turf they kill. These can be serious plant pests.
Adult Japanese beetles are very pretty. They are only about -inch long, but their bodies are stout. Their shells are metallic green and they have copper wings. As you were digging in the garden, you may have discovered them in their larval stage. They are a white C-shaped grubs that like to eat the roots of your turf.
They lay their eggs in June and July, usually near the rootline of grass. In a few weeks, the eggs will turn into grubs that will feed on the roots nearby. It is a big cycle and they want to keep us busy.
If your yard has a large grub population, chances are the chemicals you applied this spring to kill grubs worked on your lawn. So where are the beetles coming from? The neighbor s yard. The adult beetles can fly at least mile.
First thing to remember when you think about your beetle battle: They are here to stay, so you will never completely get rid of them. Just like the emerald ash borer, we just have to adjust our habits to include them in our landscape.
If you only notice a few beetles in your yard, be thankful. Hand-pick those beetles from your plants so they aren t damaged.
Another way to protect your plants is to cover them. You can pull a parachute of nylon netting or polyester row covering over them so the light and rain can get in, but the bugs can t. You can also get tough and spray the area with an insecticide specifically formulated to kill Japanese Beetles that contain chemicals like carbaryl, malathion, methoxychlor, and rotenone.
There are also many biological controls without chemicals. Look for parasites, nematodes, and fungi to fight them in a natural way.
I m not a big fan of beetle bags. These traps can be another way to minimize damage, but they also lure legions of beetles to other parts of your yard.
If you read the directions on the label of the trap, it says to put the trap 3 to 5 feet above their favorite food source. If you put it really close to something else they like to nibble on, like roses, you may have more damage to your rose bed because you were luring the beetles to it.
Traps are baited with the chemicals that make the beetle think it has found the perfect place to eat and mate. Once the pheromone scent lures them in, the trap won t let them out, and they are left there to die. From June through September, you can catch thousands of them.
The only way the bag treatment will be successful is to get the whole neighborhood involved. One or two traps per acre may have an effect on an area.