site logo

The Colorado Potato Beetle

The Colorado potato beetle showing stages of development and work on a potato plant. Note the small patch of eggs and different sized grub on the plant and the grub, pupa and adult at side.

This is one of the worst pests of the potato. As the name would imply it came originally from Colorado but is common now all over the country. The full grown insect is short and thick with a hard shel

, striped with yellow and black. The grubs, on the other hand, are soft and red or orange with black spots. Both the grubs and the beetles feed on potatoes and often completely strip them of their leaves. Since they feed on foliage they can be very quickly destroyed by dusting or spraying the plants with a poison such as Paris green or arsenate of lead. The patches of yellow or reddish eggs are found mostly on the under side of the potato leaves. When the fat grubs are full-fed they go into the ground and change to pupae and later to the striped beetles. This pest should not be mistaken for the so-called old-fashioned potato beetles which are long and slender and either bluish grey in color or striped with yellow and black. These are blister beetles and are entirely different.