Japanese Beetles


Japanese Beetles are one of the most destructive insects found in Missouri today and are marching west. They originated in Japan, but have been in the US for several years. Only recently have they been found in large numbers in this area and they are coming with a very large appetite. Adults begin emerging from the soil from mid-June to August. Beetles survive as adults for several weeks, and their longevity, coupled with the long interval over which emergence occurs, means they are present for two months or more in some areas. Therefore, it may be necessary to spray for this pest several times during the summer if they are present in large numbers in your trees and landscape beds to prevent defoliation.

Japanese Beetle
Japanese Beetle

Adult Japanese beetles are a brilliant metallic green color, generally oval, 3/8 inch long and 1/4 of an inch wide. The wing covers are copper-brown and the abdomen has a row of five tufts of white hairs on each side

Japanese Beetles can quickly defoliate over 220 different types of ornamental landscape plants (400 world wide) by eating the tissue between the veins of leaves and flowers. This type of feeding is called skeletonizing.

Trees and shrubs most attractive to adults include: Japanese and Norway maple, river birch, pin oak, sycamore, plums, elm, cherry trees, roses, crape myrtle, flowering crab, willows, lindens, and Virginia creeper. Any flowering tree or shrub will also be a favorite target of this pest. The white grub in the larva stage will also feed on a wide variety of plant roots of ornamentals and turfgrasses. The main concern in our area at the present time is adult beetle damage to broad-leaved plants.

Japanese beetles are increasing dramatically in Missouri and wet years like this tend to favor insects like the Japanese beetle. Due to our wet weather, we expect Japanese beetle damage to be significant in Missouri this year.

Japanese Beetle Damage
Japanese Beetle Damage

Therefore, please continually scout your trees and landscape beds for this pest. If you do not see this insect now, it is safe to say you probably will before the summer is over. Japanese Beetles also send out scouts to expand their range. If you only see a few beetles during your inspection, it is best to catch them and put them in a jar of soapy water to kill them. A dead scout does not return to bring more beetles to you area. Each year their numbers will multiply significantly so a few this year may become hundreds next year and possibly thousands the next year and so forth.

If you find evidence of Japanese beetles feeding on your trees or plants, please call Central MO Turf Management immediately. This insect is a very serious threat to your landscaping efforts and its control should be taken very seriously. We are beginning spray operations now for the Japanese beetle, in addition to all other chewing insects that can attack your landscaping and ornamental trees.

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