Japanese Beetles
The adult Japanese beetle is one-half inch in length and metallic green in color with bronze-green streaks on their wing covers. They have five small white tufts projecting form under the wing covers on each side and a sixth pair at the tip of the abdomen. These white tufts help to distinguish them from similar metallic green or coppery colored beetles.
Life Cycle
After spending the winter in the grub stage, deep in the ground, the Japanese beetle will slowly rise to the soil surface and pupate. After a few weeks, adults emerge and shed their pupal skin. This can occur as early as mid-May, but more commonly takes place during the four to six weeks period between June and mid-July. The highest populations of adult Japanese beetles can be found in the Ozarks during the first two weeks of June and then numbers begin to decline in mid-July. Individual beetles live about thirty to forty-five days.
Soon after emerging, the beetles will feed and mate and the female beetles will drop to the ground and deposit forty to sixty eggs in small batches approximately two to three inches deep in the soil. Egg laying is favored in the damp soils found in lawns, golf courses and pastures, thus starting the life cycle over again.
Feeding Patterns
Japanese beetles can feed on more than 300 species of plants, ranging from roses to poison ivy. The beetles usually feed in groups, starting at the top of the plant and working downward. Adults feed on the upper surface of foliage, chewing out tissue between the veins. This feeding pattern gives the leaves a skeletonized or lace-like appearance.
Some of the most common plants that Japanese beetle adults feed on include:
- Small Leaf Linden
- River Birch
- White Birch
- Roses
- Rose of Sharon/Althea
- Crepe Myrtle
- Purple Leaf Plum
- Cherry/Weeping Cherry/Sand Cherry
- Flowering Crabapple/Apple
Japanese beetles are also fond of certain weeds and non-economic plants such as Bracken Elder, multi-floral rose, poison ivy, and wild fox grape. Elimination of these plants whenever possible helps to destroy the possibility of infestation.
Control
We have found the best way to control Japanese beetle adults is to treat the plants with an insecticide that lasts about 25 days on the plants. The Japanese beetle will normally stay off the treated plants.
We also recommend setting traps. Japanese beetle traps can be found in many lawn and garden centers. The traps use a sweet smelling food-type lure that attracts and captures the beetle. The trap's scent will last about 20 days. You will need to check the traps and change them as needed. The trap should be hung away from the area you are trying to protect and 10-15 feet away from gardens and landscape plants.
Please contact your RYANPro for assistance with protecting your landscape plants from this pest.