Some are orange, some are yellow, some have spots, some do not, and sometimes Larger Elm Leaf Beetles are considered a small pest.
Individual Larger Elm Leaf Beetles have a variety of forms. The most recognizable version is yellow with two large brown-black spots on the bottom of the elytra (wing covering) and two lighter spots by the head. As their name suggests, they are found on elm trees where there larval form devours leaves. Hazel, pecan, and birch trees are also a host plant. This species rarely defoliates a large area, but occasional outbreaks happen. It is not as troublesome as other elm-feeding beetles like the Elm Leaf Beetle. Signs of caterpillar presence include the skeletonizing of leaves and a growing brown appearance to foliage, almost as though the leaves were scorched.
Adults stay in the canopy and females lay fertilized eggs on the bottom of leaves. Newly hatched larvae are a metallic red-brown color and they immediately start chewing the fleshy parts of leaves, leaving the thick veins behind. When ready to pupate, they move down the tree into soil and stay there through winter. Adults emerge in the spring. Because only one generation is produced each year, they rarely wreak havoc on a significant scale. When populations are large, however, they are considered a more serious pest. Natural controls like parasites and predators reduce the population the following year, stopping outbreaks from becoming widespread.
Larger Elm Leaf Beetles are found most often in hardwood forests and woodlands that have elm trees in abundance.
Scientific Name: Monocesta coryli
Size (Adult; Length): 10mm to 16mm (0.39in to 0.62in)
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.
Antennae: Beetles have a pair of antennae on the head used as sensors.
Head: The head is home to the insect's eyes, antennae, and mandibles (jaws).
Thorax: Holds the three pairs of legs as well as vital internal organs.
Elytron: One of two wing cases on a Beetle that protects its wings (plural: elytra).
Wings: Appendages used for flying and kept under the elytra until needed.
Abdomen: Houses organs related to circulation, reproduction, and excretion.
Legs: Beetles have three pairs of legs located at the thorax, numbering six legs in all.