Scientific Name: Leptinotarsa decemlineata
Colorado potato beetles are oval shaped about 3/8 inch long and have black stripes on the body and a brown head. Eggs are orange and usually found on the underside of leaves. Larva are red-orange in color with dark spots along each side of their body. Adults and larva eating on the tops of potato leaves are very easy to see.
They are common throughout the Arizona and overwinter in fields and gardens. They become active at the same time as our potatoes start to grow in the spring. Adult beetles, their eggs and larva may be found on your potato plants at the same time.
Colorado potato beetle adults and larva eat other members of the nightshade family including eggplant, tomato, and peppers.
Early or late planting, crop rotation and mulching may help in the control of the beetle. Good garden practices such as weed control, removal of debris and watching your plants closely is probably the best way to control the Colorado potato beetle in your garden.
Floating row covers may be placed on top of your potato plants which should help stop the hungry potato beetles. Companion planting or catnip, sage or possibly tansy may discourage the beetles. Mulching with straw may provide habitat for predators like lady bugs, lacewings, or ground beetles.
Hand picking the adults that emerge in the spring and squishing the eggs found on the leaves of the potato is probably the most effective method of control. The larva do the most damage so by preventing the hatching of the eggs along with the destruction of adults you could reduce the damage to your veggies. Colorado potato beetles have a remarkable ability to develop resistance to insecticides. You may try neem oil or drowning them in a bucket of soapy water, or a jar of alcohol.