Hornets Are Eating My Lilac

Hornets are a type of social wasp and are closely related to yellow jackets and umbrella wasps. According to National Geographic, there are about 20 hornet species, and most of them live in Asia. Like other social wasps, hornets make "paper" nests, and they don't leave a stinger when they sting. Hornets are considered beneficial insects because they eat pests like caterpillars and grasshoppers. However, the European, or giant, hornet also feeds on lilac bushes.

The European hornet looks something like a yellow jacket, only bigger. These hornets are the largest ones in North America, growing up to 1 1/2 inches long. This hornet's head and thorax are reddish brown, and the abdomen is black with yellow markings.

European hornets chew bark off lilac bushes and other plants in order to feed on the sap below. In addition, the bark is used to build nests. European hornets can strip the bark off smaller twigs, causing the part of the twig above the stripped bark to die. In addition, lilac leaves may turn prematurely brown in late summer and early fall. If the twig tries to regrow, it develops an unusual swelling just above the injured spot.

European hornets aren't as aggressive as some other wasps, although they will sting to protect their nest. Because they're beneficial insects, they shouldn't be destroyed unless it's absolutely necessary. The only way to control European hornets is to find and destroy their nest. European hornets fly at night, as well as during the day, and they're attracted to lights. Use a flashlight with red cellophane over the lens, and wear protective clothing. Use a pressurized wasp and hornet spray with a 10 to 15 foot range. Spray the nest at night when most of the hornets are in the nest and they're less active. Be ready to move quickly away if hornets come out of the nest. You may need to spray again the next night. Yellow jacket baits that contain poisoned meat don't work on European hornets because they eat live insects. Consider using a licensed professional pest control operator to remove nests because he's trained and has the right equipment to do the job.

European hornet nests are usually found in protected areas like inside hollow trees or in sheds, birdhouses, attics and porches. Nests can be 2 or 3 feet long and contain up to 1,000 hornets, although most nests contain 300 to 500 workers. The nests are surrounded by a thick, papery covering and may have more than one entrance. Hornet populations die off when the weather turns cold and nests are never reused. New nests are made each year.

European hornets were introduced into the United States during the 19th century, and were reported in New York in 1840. As of 2011, it could be found in most of the eastern United States as far west as the Dakotas and as far south as Louisiana.