Japanese beetles were first found in North America in a New Jersey nursery in 1916. With no natural predators to regulate their populations, the insects soon began to devour plants in gardens up and down the Eastern Seaboard. Today, the Japanese beetle is still one of the most common and destructive invasive pest species in North America, particularly on the East coast.
If you have a garden here in Maryland, chances are you’re already familiar with these pests which can be distinguished by their metallic green heads and copper-colored wings. You may also recognize the damage they leave in their wake – skeletonized leaves with nothing left but veins and stems. The good news is there are steps you can take to protect your garden and prevent a full-blown beetle infestation.
Apply Neem Oil
This combination fungicide-insecticide-miticide can not only be used to eliminate adult Japanese beetles in your garden, but also help to control a number of other diseases and pests as well. It’s a safe, organic option that can be effectively used throughout the growing season.
Target Grubs
One of the best ways to prevent Japanese beetle invasions is to eliminate them while they’re still grubs growing in the soil. The best time to treat the soil for grubs is between mid-July and the end of September. You can do this in a variety of ways. If you’d rather not use pesticides in your garden, you can use Nematodes (microscopic parasitic worms) to eliminate grubs populations. Otherwise, there are a number of curative pesticide options available as well.
Manual Removal
There’s nothing wrong with getting rid of Japanese beetles the old-fashioned way. If you start to notice a few beetles here and there in your garden, you can prevent the problem from getting worse by removing them from plants by hand. It’s easiest to do this in the morning when beetles are still slow and lethargic.
Some people use sticky pheromone traps to capture and kill Japanese beetles as well, but in some cases this can make infestations worse by attracting more of the beetles to your garden. Instead, your best bet is to keep a close eye out for grubs in your turf and apply neem oil concentrate as soon as you see mature beetles in your garden.