Monday, June 6, 2016

Japanese Beetles

Japanese Beetles have emerged from the ground and are munching down on our ornamental plants like there is no tomorrow, leaving behind lacelike foliage everywhere they dine. The warm weather has also caused the cockroach to move inside for a little air conditioning (can you blame them?) and the calls are rolling in about chinch bugs and fleas.

Japanese Beetles come out of the ground here around the beginning of June (as you probably noticed) as beetles. In parts of the country, they are the number one damaging insect to ornamentals, and they seem to be gaining a stronghold in the Lowcountry. As recent as five years ago, I can remember talking to friends in Charlotte whose plants were getting devastated by this ferocious eater, and they would say how lucky we were not to have them down here in the Lowcountry. Roses and Crepe Myrtles are some of their favorite plants.

Once the Japanese Beetles come out of the ground, they eat and mate. A female returns to the ground to deposit between 40 and 60 eggs (you can see how the populations can grow rapidly). The female beetle must burrow in the ground to lay eggs and the eggs need moisture to survive. A well irrigated landscape is a lot easier for the beetle to dig in than a dry, hard, area. The adult beetle dies off and the eggs turn into grubs over the summer. By mid to late August the grub is full grown and overwinters in the soil. In late May to early June the adult (beetle) emerges again and the life cycle starts over.  

The grubs from this beetle damage grass and other plants by eating the roots. Using a product like Grubz Out in late August or early September (if your grub populations warrant treating) or in April will help your turf; however, do not fool yourself into thinking all your beetle problems will be solved.  The adult beetle can fly for miles to chow on your precious ornamentals! Milky Spore is an organic option that seems to do a good job now that our grub population is high enough for the spores to have a steady food source.

Using a ground drench systemic insecticide in the early spring like Dominion will help protect your plants, and you might get lucky and kill a few grubs while you are drenching! Once the beetles are on your plant there are many good contact insecticides that you can use to kill them as well as some organic controls. Since contact insecticides have limited residual activity, plan to reapply the product according to the label.

Traps for Japanese Beetles are a little controversial. The attractants they use (one is a virgin female beetle scent) can lure more beetles to an area than the trap can trap! Many ornamentals on the way to the trap and near the trap can suffer extensive damage.

Roaches, fleas, mice, and chinch bugs are becoming uninvited guest in many homes and yards. Are you protected from these unwelcome guests?