Tuesday, June 2, 2009

Colorado Potato Beetle

This is the Colorado Potato Beetle (Leptinotarsa decemlineata). They are common throughout most of the United States. Pictured here are the eggs, larva and the adult. As adults they measure approximately 3/8 of an inch in length. Their bodies are rounded with a reddish head and thorax. Numerous black markings are on the back of the head and thorax. Right in the center of the head you will notice a triangular mark. The elytra are yellowish in color and have ten black vertical stripes. Adults will overwinter in leaf litter or other sheltered places. In the spring they become active again and begin seeking mates. After mating, the female will deposit orangish-yellow eggs on the underside of leaves of the host plant. In the case of these beetles the host is potatoes, but may also be found on a variety of other plants including eggplant, horsenettle, tobacco, buffalo bur, thorn apple, tomato, pepper, common nightshade, belladonna, etc. Once the eggs hatch the reddish colored larva will feed on the leaves of the plant. Once the larva reach full size (in about 21 days) they will drop from the plant and burrow into the ground to pupate. In approximately 10 days the adult will emerge. In 1811 a man by the name of Thomas Nuttle first discovered this beetle, but it was not fully described at that time. In 1924 a man by the name of Thomas Say studied this insect at length. It was found on Buffalo bur in the Rocky Mountains. Later it became apparent that its food of choice was the potato plant when vast acres of these plants were found destroyed by the eating habits of both the larva and the adult. With the prevalence of potatoes and other food favorites of this beetle it has been able to expand its range exponentially. By 1974 it had reached the Atlantic coast. We find a few of these on the potatoes each year, but rarely in large numbers. Seven Dust helps keep them in check an protect our potato crop. The eggs and adult pictured here were photographed this year. I assume the eggs belong to the adult pictured. The larva was photographed last year and I was never able to locate the adult.


  1. Hi Shelly - Nice post. I have some minor clarifications. Thomas Say described the beetle in 1824 from specimens he collected on an expedition to the Rocky Mountains. However, he probably actually collected it in the Great Plains somewhere along the way before reaching the Mountains. The beetle was first noticed as a pest of potatoes in Nebraska in 1859, after which it took only 15 years for it to makes its phenomenal spread across the entire eastern U.S.

  2. Hey Ted, glad you stopped by. Thanks for the information. Most information I found was very sketchy. It is always nice to have further info to share. It never ceases to amaze me the resilance of insects.