My blog site is primarily dedicated to growing tropical and subtropical plants, whether as a houseplant or in the garden

How to Control Japanese Beetles

How to Control Japanese Beetles

Japanese beetles…the bane of my existence!  As a passionate gardener, I’m fiercely protective of my garden.  My tropical garden in Ohio brings me so much happiness, but it is also a lot of work.  Gardens are always under attack by a variety pests, critters and diseases including aphids, Japanese beetles, deer, and a variety of fungal diseases.  It’s never a dull day in the garden.  But when I see something attacking my garden, it’s time to take action!  Like clockwork, every July brings the dreaded Japanese beetle to my garden.  They are mainly contained to the Eastern part of the United States (for now).

What Japanese Beetles Do

In short, they wreak havoc on your plants!  If left unchecked, they will disfigure and defoliate your plants.  This year in my garden, they have attacked one of my hardy bananas (Musa basjoo), my 4 O’Clocks, and they love eating the flowers on my tropical hibiscus flowers. They even started to eat the leaves of my Brugmansia which are toxic!  I wonder if they will die?  They have started to skeletonize various leaves, but I put a stop to it (keep reading and I will tell you how).  In addition, they will also eat the spent tropical hibiscus flowers but sometimes I see them make holes in fresh hibiscus buds.  If you have roses, they LOVE rose buds.  I no longer have any roses in my garden so I don’t have to worry about this anymore!  Take a look at what the damage looks like in the pictures below.

The photograph above is a leaf on my Musa basjoo.  The photograph below shows my 4 O’Clocks.

Awful right?

How to Control Japanese Beetles

First of all, did you know that the grubs in your lawn turn into Japanese beetles???  First the grubs will eat the roots of your grass, and then they will grow up into Japanese beetles!  How rude.  If you have grubs, having your lawn treated for grubs will help keep your Japanese beetle population down.  I’m not here to recommend or promote any harsh chemicals because I greatly minimize the usage in my own garden, but if your lawn has grubs, you may want to do some research and choose a product that you are comfortable with.  Preferably, do some research on organic treatments!  An indication that you have grubs in your lawn include seeing dead patches of grass in late summer/early fall in an otherwise green lawn.

I wanted to start with what NOT to do first.  Do NOT use those bright yellow bag Japanese beetle traps! Why?  Because you’re basically recruiting all the Japanese beetles in your neighborhood and creating a big party for them!  You will be attracting a lot more Japanese beetles to your garden than would normally come, and not all of them will end up in the trap!  Many of them will begin to feast in their new buffet that is YOUR garden!  So avoid these bags at all cost.

Since I don’t like to use any harsh sprays unless I have to, I choose the manual approach to dealing with Japanese beetles in my garden.  It is also the safest and most effective way.  If I’m walking through my garden and happen to see one on my plants, I simply pick it off with my bare hands, throw it on the ground and give it a good stomp.  But, if I start to see quite a few, I use the following method:

  • First, I obtain a plastic cup or any other small container with no holes.
  • Add a squirt of dishwashing soap.
  • Fill the cup about halfway with tap water.
  • Walk around the garden and flick/drag the beetles to their soapy death right in the cup (see the photograph below)

If you are diligent, you will keep them under control, all without the usage of any harsh chemicals.  The good part is that they will not appear all summer.  They’ll normally last 1-2 months or so.  I am a big proponent of minimizing the impact on ourselves, our pets and the environment by using no harsh chemical sprays in our garden.

Another way to control Japanese beetles would be to simply plant things that they don’t like to eat!  Do your research online.

Happy Japanese-beetle picking!