Even though it is still several more weeks before summer will officially arrive, this past week has definitely given us a sample of what summer will probably be like. It will be hot. But let's hope that it will not be as dry as it was last year.

Along with summer, we always encounter a few aggravating insects that we have to deal with. Since I have already started receiving phone calls about Japanese beetles and bagworms, let me share a little information with you about both of these pests. If you know about them before they arrive, you can better deal with them when they get here.

Japanese beetles were first reported in North America in 1916 and now occur throughout the eastern United States. They feed on over 275 different kinds of shade and fruit trees, shrubs, flowers, small fruits, and garden crops and will also eagerly feed on many weeds. Some of their favorite foods are roses, crape myrtle, grapes, and fruit trees.

The adult beetle is what is noticed most often as they feed on the leaves of our favorite plants. They are active for about six weeks during early summer. They have a terrific appetite and can do a lot of damage to plants very quickly. When they feed, they often leave only a lacy network of veins and stems where the leaves used to be. These insects secret a scent that attracts other beetles, so usually, when one starts feeding on a plant, many others join in. Most plants can withstand the loss of quite a few leaves and then fully recover, but home gardeners usually like to protect their favorite ornamental plants from this type of damage.

Most of the common garden insecticides, such as Sevin or malathion, are very effective on Japanese beetles but only provide temporary relief. Unless treatments are repeated every few days, more beetles will be attracted to the plant and damage will continue.

We usually don't see them, but the juvenile stage of this insect is a grub that lives in the ground for most of the year. These grubs feed off the roots of plants, especially the roots of lawn grasses. As the root system is weakened, it is more difficult for the grass to withstand droughts, such as we experienced last summer. When this happens, we often see spots or even large areas of our lawn turn brown and die.

Many homeowners are familiar with a product that is sold commercially for the control of Japanese beetles. This product is a preparation of Bacillus porilliae and is referred to as Milky Spore Disease. It infects and kills only Japanese beetle grubs. It is perfectly safe for humans and pets. If this product is used, it can be applied anytime from early July until frost. But please be aware that adult Japanese beetles can travel a long distance, so just because you get rid of all the grubs in your lawn does not mean that adult beetles won't travel from your neighbor's yard into your yard or garden.

Japanese beetle traps that can be purchased at most of the hardware stores or garden centers will usually catch a lot of beetles. But the ones they catch may not be the ones eating on your plants. These traps release a scent very similar to an adult beetle. This scent attracts many other Japanese beetles to the trap. Because of this, it is easy to see that you don't want to place one of these traps close to your prized flowers or fruit trees, because you will just be attracting beetles to them. Place the traps away from these plants. Better still, give them to your neighbors and let them place them in their yards. If you use one of these traps, you need to empty them fairly often. Once the trapped beetles die and begin decaying, they release ammonia that actually repels other beetles.

Bagworms are those little oblong things that look like drab Christmas tree ornaments dangling from shrubs. The thing you see dangling from the shrub at this time of the year is the cover that protects the eggs that the female laid late last summer. These eggs will start hatching in late May and June.

Although these caterpillars feed on a lot of different types of plants, their favorite plants are cedars, junipers, and spruce. It is not uncommon to see one of these evergreen shrubs with literally hundreds of these little bags hanging on it. When you see this, you can know that unless the owner does something pretty soon the plant will probably die. Once the bagworms become established, they can do considerable damage in a short period of time. Some of the plants they particularly like, such as Leyland cypress, do not recover too well from severe defoliation.

If you are paying attention to your landscape plants, you should be able to notice a bagworm infestation very soon after it starts. If you notice them soon enough and the plant is not too large, you can snip the little bags off with scissors. Place them in a plastic grocery bag and discard in the garbage can.

If you must use insecticides, the time to treat is immediately after the eggs hatch and before the young caterpillars establish their own "bag." Once they build their "bag," it will be difficult or impossible to treat them with chemicals. Several of the common insecticides used around the home, such as Sevin or Orthene, are very effective on these worms.

If you have access to the Internet, you can get detailed information from Cooperative Extension about these pests as well as many other pests you may encounter in your yard and garden. Go to http://www.ces.ncsu.edu/depts/ent/notes/ and select the type of pest you want more information about. Then select the specific pest from the menu. If you need more information, please contact me at your Cooperative Extension Center by calling 910-671-3276.

E-mail address: Everett_Davis@ncsu.edu

Mailing Address:
P. O. Box 2280
Lumberton, NC 28359-2280

Phone: 910-671-3276
Fax: 910-671-6278

Date Created 6/16/08