Elm Leaf Beetles
Facts, Identification & Control
Pyrrhalta luteola (Muller)
AppearanceWhat Do They Look LIke?
Elm Leaf Beetle image licensed under CC
- Size: Adult elm leaf beetles are about 13 mm long.
- Color: They are yellow to olive colored. They have a dark band on the outside edge of each wing cover. The larvae are yellow and have a black stripe.
How Did I Get Elm Leaf Beetles?
Because their diet consists of outdoor plants, these insects typically don't live in houses. However, toward the end of summer, adults begin to search for safe spots in garages and attics to overwinter. When the pests awaken in spring, they often have trouble finding their way outside. Homeowners may see large numbers of them in living spaces.
How Serious Are Elm Leaf Beetles?
As their name implies, these insects eat the leaves of elm trees. Elm leaf beetles usually don't kill trees on their own. Rather, they weaken it, making it prone to disease and damage from other pests. Indoors, they are just a nuisance. They do not harm people or the wooden components found in homes.
Signs of Infestation
In homes, the mass migration of the adult beetles is the most obvious sign. They spend the winter in attics, crawl spaces, or hiding in the living space. Outdoors, elm trees that show browning leaves and premature leaf drop can indicate elm beetle activity. A closer inspection of the plant would be needed to detect the feeding larvae.
How Do I Get Rid of Elm Leaf Beetles?What You Can Do
There are a variety of products that will control elm leaf beetles while they infest trees. These are biological agents, insecticidal soaps and oils, and systemic products. The specialists at the garden center can help with these. Follow label directions for these products to help reduce the number of beetles that try to enter the home. It may also limit the amount of damage that the beetles might do.
The quickest way to remove these insects from the inside of the home is with a vacuum cleaner. To keep elm leaf beetles from entering homes:
- Check outside for openings.
- Repair screens on windows, attic vents, and crawl space vents.
- Make sure exterior doors close properly.
- Add weather-stripping where it is damaged or missing.
An insecticide barrier on the outside of homes will reduce the number of adult elm leaf beetles that gather there, and add protection from invasion. The choice of product and formulation is important to ensure effectiveness. Your local pest control professional will have the products and the equipment necessary to get the job done.
Behavior, Diet & HabitsLife Cycle & Reproduction
Elm leaf beetle females can produce up to 800 eggs in her life. These eggs usually appear underneath the leaves of the selected plant. Larvae hatch, feed, and then pupate in crevices in the tree toward the end of summer. In some areas of the country, two or three generations occur during the summer.
In the fall, adult beetles try to find a place to spend the winter. Many times they gather on houses and then find openings that lead inside. When they are trapped inside the home, they gather at windows and doors at the onset of spring. Mating occurs at this time.