My rose bushes are being eaten alive by beetles. The leaves and the blooms. What are your suggestions? Thanks

Japanese beetles LOVE roses. One of my reference books describes Japanese beetles as “beautiful little metallic green insects with bronze wing covers”. Anyone who has fought an infestation of Japanese beetles would take issue with this description!

Japanese beetles were accidentally introduced into this country in 1916. They arrived in New Jersey, probably hiding in their grub stage in the soil of imported nursery stock. The beetles made their way to Kentucky by 1937.

Japanese beetles prefer to feed on plants in full sun. They will usually feed in groups that start out at the top of the plant, working their way downward. A single beetle won’t do much damage, but groups feeding in your garden can be devastating. They will devour blooms, ripening fruit, and tender leaves with smell veins. One some plants, they will eat only the tender tissue between leaf veins, giving the leaves a lacy appearance characteristic of beetle damage.

A little information about beetle life cycles might be helpful. Adult beetles emerge from underground over wintering sites in June; they begin feeding, starting on low growing plants and eventually flying their way up into trees. Adults will live for 30-45 days, with populations reaching their peak in July. Just before dying, female beetles will lay their eggs in lawns or other grassy areas just below the soil surface. The grubs that hatch from these eggs are grayish white with brown heads and have a characteristic C-shape. They will feed on grass roots until colder weather drives them further down into the soil below the frost line. As the weather warms again in spring, the grubs move back up and resume their feeding on roots. The grubs will then pupate in the ground emerging as adults to start the cycle all over again.

To control Japanese beetles it is most helpful to eliminate the adult populations. You can do this by attacking them early in the morning or in the evening when they will tend to be slow moving and sluggish. Take a bucket of soapy water out to the garden with you and shake the stems holding the beetles over the bucket. They will fall in and drown. You can place a sheet under small trees and shake them and then fold it up quickly to capture the beetles before squishing them. (Make sure this is an old sheet, you won’t want to reuse it.)

If you have lots of beetles on your rose blooms, once you have had some bloom damage from chewing, it is usually a good idea to leave the damaged bloom on the plant. The beetles will tend to “finish off” a bloom that has been chewed on already, before going on to the next one. This way you can limit damage somewhat.

Control of grubs is usually not warranted in the lawn. Statistics show grubs damage to lawns occurs in only about 5% of lawns. (Of course if you are in that 5%, you might take issue with this statement.) Grubs chewing on grass roots will cause patches of brown grass in your lawn. Grub damaged turf will pull easily away from the soil-just like pulling up a rug. To determine whether or not grub populations are high enough to warrant applications of pesticides, cut out a one foot square of damaged turf. If you see more than 10-12 grubs in that one-foot patch, you might want to apply a control.

I recently had one of our listeners call in and say that she had discovered a recipe to trap and destroy Japanese beetles. She mixed ¼ cup of Joy Dishwashing liquid with ¼ cup of lemon juice and a pint of water. Put the mixture in a bowl and set it near plants that the beetles are attacking; she says they will come over and drop right in to meet their demise.

Here’s another recipe that you might want to try. Collect a half cup of beetles; mash them up, mix with 2 cups of water and strain. Mix ¼ cup of this bug juice and a couple of drops of Ivory liquid hand soap with 2 cups of water and use as a spray.