The Asiatic red lily bug, or red lily beetle, can be devastating to the lilies in your flower beds. The bugs attack all parts of the plants, and because of their size, the larvae can be hard to spot. You can fight an infestation of these pests, but it requires patience and daily monitoring to keep them from taking over.
Asiatic red lily bugs have red bodies with black legs and black heads, and are similar in appearance to oblong ladybugs without spots. They lay tiny (3 mm long) bright orange eggs. The larvae are orange as well, but soon after they emerge they spread their sticky black feces over their bodies to discourage predators.
The red lily bugs are voracious eaters of bulbous flowers, especially lilies. Both adult and larval forms of the bugs eat leaves, flowers and stems of the plants from spring to fall. As the bugs destroy the leaves, the plant's ability to produce food through photosynthesis fails. This weakens the plant, may prevent it from producing flowers the following season, and in severe infestations can kill it.
History and Spread
The Asiatic red lily bug is native to mainland Europe and Asia. It spread from there to England, with the first case reported in the 19th century. By the 1940's the bugs had become established in that country. The first reported sighting of Asiatic lily bugs in North America occurred in Canada in 1945; since then, the bugs have spread southward into the eastern states of the U.S.
The adult bugs emerge from the soil in the spring and mate soon after. The females lay lines of eggs on the underside of lily plants, and the larvae emerge seven to 10 days later. The larval stage is the most destructive in the bug's life cycle. The larvae strip the plant's leaves and flower buds before dropping off the plant to pupate on the ground. In the fall, the adults burrow into the soil to survive the winter.
Controlling an Asiatic red lily bug infestation requires vigilance. You'll need to check your lilies daily and pick off and crush any adults, eggs or larvae you find. An easy way to find the adults is to lay a white or light-colored fabric on the ground underneath the plant, then shake the plant. The adult bugs often drop to the ground with their black undersides facing up, making them easy to spot on the light-colored background. Larvae are more difficult to see, so you may want to treat the plant with an insecticide to help control them. Insecticides containing imidacloprid work well on Asiatic lily bugs, but be aware that this chemical may also be partly responsible for colony collapse disorder of honeybees.