Colorado Potato Beetle Leptinotarsa decimlineata
The most dreaded leaf beetle probably is the Colorado Potato Beetle below. It used to destroy potato crops completely. This is mainly due to the fact that it multiplies very quickly indeed: three weeks after being laid an egg goes through all stages of beetle life and is an adult itself, capable of laying eggs. And each female will lay some 500 eggs! Yet, this once was a scarce beetle. It used to live in a small portion of the State of Colorado. It used only a small amount of food plants (nightshades only) and was considered a rarity by coleoptorists. But then the potato arrived. The potato is a member of the nightshade family as well. The Colorado Potato Beetle quickly adapted himself to eating potatoes and soon it became so abundant that it destroyed potato crops all over the US. By the mid-1800's it was imported to Europe, where it soon became as destructive as it used to be in the USA. All kinds of pesticides were used to kill the animal, but usually in vain, for the animal quickly immunized itself to most insecticides. The best definition I ever read about this beetle is this one: the Colorado Potato Beetle is a beetle still mad at us for eating his potatoes. The animal does not really look like most other leaf beetles, but rather like a large Lady Beetle. It suddenly turned up in our garden in the summer of 2004.