True to its name, the Cottonwood Leaf Beetle is found in groves and forests filled with cottonwood trees so its caterpillar can feast.
Cottonwood Leaf Beetles have similar coloring to the pesky Colorado Potato Beetle, but their very different pattern makes it easy to differentiate between the two. The Cottonwood Leaf Beetle is yellow and black. Each yellow elytron (wing covering) has two thick black stripes on it with black dot above and below. The side edges of the wings are orange. The sides of the thorax are also orange, each with a single black dot in the center.
Adults are active in the spring when females begin laying groups of yellow, tubular fertilized eggs on the new leaf growth of cottonwood and willow trees. The larval caterpillars will feed on the leaves until they develop into pupae. They cocoon themselves right-side-up on leaves, and emerge as adults in a relatively short span of time. In warmer regions, as many as 4 or 5 generations can be produced each year.
Caterpillars are yellow with segments and side ridges that almost resemble the texture of alligators. Each ridged segment has a black dot and the tips share a black line that runs from head to rear. They chew the green parts of a leaf, leaving behind the veins, giving the leaf a skeleton-like appearance. Large numbers of Cottonwood Leaf Beetle caterpillars can defoliate young trees, harming their health and growth. Removing weeds in the vicinity of the trees where adults overwinter can help reduce the amount of reproduction that occurs in the spring. Spraying chemical insecticides on the affected tree can also control populations of this beetle.
Scientific Name: Chrysomela scripta
Size (Adult; Length): 5mm to 9mm (0.20in to 0.35in)
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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.