Japanese Beetles: How to Spot Damage and Control Beetle Infestation

​It's that time again! Invading hordes of Japanese beetles begin their quest to mate and eat all of our tender plants this time of year, so we thought everyone could benefit from some useful information about them and how to stop plant damage before it begins.


The first step is to recognize beetle damage. Oftentimes, you will see the beetles themselves on your shrubs, trees, and plants. They are slightly smaller than a penny and have an iridescent green/brown body. They can often be found on roses, but will eat practically any tender-leaf plant it lands on. If no beetles are present, damage to leaves can be white or light brown and have a lacy appearance to it. Now that you know what the damage looks like, we can discuss treatment options.


There are several ways to control Japanese beetles. The most common way is to purchase the Japanese and Oriental Beetle Traps. These traps contain a canister with a pheromone that attracts the beetles into the bags. While very effective, these traps must be emptied daily or every other day. We recommend emptying the bags into a bucket with a Sevin solution so that you can ensure the beetles are killed. One misconception about the traps that we hear quite often is that folks believe that placing a trap in the affected tree or shrub – or very near affected plants – is the correct way to place them. This is not the case! In fact, you might inadvertently cause more damage to your plants because the beetles will stop to munch on them before going into the trap. We recommend that traps be placed at least 30 feet from affected trees, shrubs, and plants.


Another way to control beetle damage is to use a granular systemic product, such as Bayer Advanced Rose and Flower Care or Bonide Systemic Granules for Insect Control. Both of these products are placed at the base of a plant and watered in thoroughly. The product is then absorbed through the roots and will kill beetles that ingest any part of the plant.


Lastly, you can also use products such as Sevin Concentrate Bug Killer or Sevin Dust to directly kill beetles that you see on your trees, shrubs, and plants. This is a great way to instantly kill the beetles, however, you must continually treat with these products because they will wash off with rainfall or watering.


As we are entering July, it is important to note that we are at the height of the life cycle of the beetles, so they have another six to eight weeks left until they leave! If you have any questions, please feel free to stop by the garden center! Until then, happy beetle hunting!

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