As I write this, my daughters and I are enjoying a stay in The Galena Territory. We have shopped till we dropped on Main Street, enjoyed an afternoon at the pool, and played Sorry and pinochle. I still haven’t managed to win a single game. What I have managed to do is notice the damage on the Linden tree outside our townhome. Every morning, the pile of skeletonized leaves on the sidewalk gets larger. While we are enjoying burgers, fries, and ice cream cones, the Japanese Beetles are feasting on that Linden tree morning, noon, and night. The Japanese Beetle was first discovered in southern New Jersey in 1916. They quickly spread across the eastern U.S., arriving in Chicago in 1932 and into the St. Louis area by 1936. Although largely confined to urban Illinois until the late 1990s, they have become a major pest in many rural areas.
The Japanese Beetle life cycle is 12 months long. The life cycle can be broken up into two parts: the grub stage and the adult stage. They can be very destructive during both stages.
For 10 months out of the year, the Japanese Beetles are in the ground in the form of larvae or grubs. The grubs feed on turf grass roots and the roots of ornamental plants. They can cause extensive damage to your lawn or ornamental plants. One sign of grub damage to lawn is small, irregular patches of dead or dying grass. To determine if you have grubs, pull up the damaged grass and look for small C-shaped grubs.
In mid to late June, the grubs emerge from the ground in the adult form of Japanese Beetles. The adult insect is about a half inch long and is a shiny, metallic copper color.
The adult beetles spend six weeks eating and mating. They feed on over 300 types of plants. They cause significant damage in the six weeks they are out flying around. They eat leaves, ripening fruit, and flowers. The plants I have seen damaged by Japanese Beetles this year include Birch trees, Hydrangea shrubs, roses, herbs, and Linden and maple trees. More and more damage will be evident as we move through the month of July.
When protecting your lawn and plants from Japanese Beetles, a multi-faceted approach is best. Because the beetles are both a grub and a flying insect, you may want to try to control them at both stages of their life cycle.
Milky Spore is an organic, pet-safe product that kills the grubs. It is available in a powder form that has a 10-year product guarantee. Once you apply it, you don’t have to apply it for 10 years! It can be applied anytime the ground is not frozen. Imidacloprid, which is the active ingredient in GrubEX, is also an effective way to kill the grubs. It is usually applied from spring to early summer.
The adult beetles can be controlled through cultural or chemical means. One popular cultural control is to simply cut off the top of a plastic milk jug, fill it with soapy water, and knock the beetles from the plants into the milk jug. Another very controversial cultural control is Beetle Baggers. The Beetle Baggers are designed in such a way that a lure is hung over a plastic bag. When the beetle flies to the lure, it gets caught in the bag. The bags can fill up pretty quickly and need to be changed often. This option is controversial because the baggers attract beetles. If you choose this option, be prepared to face some questions from concerned neighbors.
There are many very effective chemical means of controlling the adult Japanese Beetles. If you have plants in your yard that are particularly susceptible to damage, consider using a systemic insecticide. There are systemic insecticides that can protect your trees and shrubs for up to one year. Bonide and Bayer both make very effective products.
There are also ready-to-use sprays that can be applied now to control the Beetle damage immediately. Bonide makes a spray aptly titled Japanese Beetle Spray. When working with any chemicals, please read and follow the label instructions.
By using a multi-faced approach in your yard, you should begin seeing a reduction of damage due to the Japanese Beetle. It is an insect problem that needs to be tackled because 1000 adult females lay 50,000 eggs each year.
Kathleen Carr is the owner of The Growing Scene, Inc., a garden center and landscaping company. She can be reached by calling 815-923-7322 or tgsinc12@msn.com. Have a gardening question? Please contact her. She will address it in an upcoming column.
