Japanese Beetles are a metallic green beetle with bronze coloured wings that feed on the tissue between the veins of plant leaves. Plants, such as roses and flowering and ornamental shrubs, fruit trees, grapes and even poison ivy, are subject to their feeding. They leave the plant’s leaves with a skeletonized appearance. When there isn’t enough leaf surface, the plant is unfortunately not able to get enough sunlight to support it’s own life, and in cases where there are many leaves damaged by the beetles, the plant will ultimately not survive.
Japanese Beetle Life Cycle
Adult Japanese Beetles live between 30 and 45 days and feed heavily on roses and many different plants and trees throughout your garden. During this time, the females lay 40 to 60 eggs in the soil. These eggs hatch within 2 weeks and the larvae begin to feed underground until the fall when the temperature drops, to which the move underground to avoid the frost. In the following spring, the larvae will return to the surface to feed again. And finally in June, the grub pupates and the adult emerges to start the life cycle again.
There are several options that can be put into place in order to control Japanese Beetles.
You can handpick the beetles off of plants and kill them by squishing them or dropping them in hot soapy water. This is easiest to do either early morning or late evening when the beetles are least active.
Nematodes are a natural and effective alternative to chemical pesticides, and have no detrimental affect on non-target species such as lady-bugs, earthworms and other helpful garden insects. Nematodes are naturally occurring microscopic organisms that, when watered in, will infest and kill white grubs living in your lawn. However, they themselves do not persist in your soil - they die off when the grub population is reduced. They can be applied anytime during the year when the soil-swelling insects are present and soil temperatures are above 12 degree C during the day.
Japanese Beetles traps use floral lures and pheromones, which attracts both the male and female beetles. They then fall into the container or bag provided (depending on the trap) and cannot get out. These traps are proven to reduce population numbers and damage due to the beetles. However, note that the lures may attract more beetles in the area than may have been present.