Green County MGA

Green County Master Gardeners Association, Wisconsin

Watch out for those Japanese Beetles!

Japanese Beetles are back!  Japanese beetles occur in every state east of the Mississippi River except Florida. The insect’s spread is apparently governed by temperature and precipitation. The beetle is adapted to a region where the mean summer soil temperature is between 64° and 82°F and winter soil temperatures are above 15°F. Also, beetles thrive in areas where precipitation is rather uniform throughout the year, averaging at least 10 inches during the summer. Japanese beetles do not feed on turf, but are an important pest of many other plants. They feed on foliage or flowers and are a major pest of over 350 species of plants, including fruits, vegetables, ornamentals, field and forage crops, and weeds. Norway and Japanese maple, birch, crabapple, rose, mountain ash to name a few of their favorite ornamentals. For more information, print the Japanese-Beetle publication.