Colorado potato beetles are the most serious insect pest of potato plants in North America. Both the adults and larvae of these ‘potato bugs’ feed on the leaves of potato plants, causing widespread damage, reducing crop yield, and even killing the plants altogether.
Potato bugs are one pest to watch out for this summer, but how can you identify them? Are there any other pest species they can be confused with, and how can you tell them apart?
What are Colorado potato beetles?
The Colorado potato beetle is a black-and-white striped insect found throughout North America. Also known as the ‘potato bug’, the Colorado potato beetle is the most important insect pest of potatoes in the United States.
Keep in mind!
Both the beetles and their larvae feed on the leaves of potato plants, and can cause widespread damage to crops.
Potato bugs are also known to inhabit tomato, eggplant, and pepper plants.
Where do potato bugs come from?
The Colorado potato beetle is so-named because it was first identified in the Rocky Mountains of Colorado in 1824. However, potato bugs are not native to Colorado and are actually thought to have originated in central Mexico. Since then, it has spread throughout Mexico and North America, and is found in every state except Hawaii, Alaska, California, and Nevada).
What do potato bugs eat?
Potato bugs are the most serious pest of potato plants in the United States. Adult beetles feed and lay their eggs on the underside of potato leaves and, once hatched, the larvae also feed continuously on the foliage of the host plant. Potato bugs prefer potato plants, but are also known to invade and destroy tomato, eggplant, and pepper plants.
Damage caused by Colorado potato beetles
Colorado potato beetles usually feed in groups and can cause severe and widespread damage to host plants. Both the adults and larvae feed on the leaves of potato plants, and the resulting defoliation can lead to significantly reduced yield and even plant death.
Life cycle of the Colorado potato beetle
The life cycle of the Colorado potato beetle consists of four distinct stages, and can be completed in as little as 30 days.
Adult potato bugs usually feed for 5 – 10 days on the leaves of their host plant before depositing a batch of up to 300 eggs. The adult beetles usually lay their eggs on the underside of leaves, where they are protected from the sunlight.
Potato bug larvae emerge from their eggs after a period of 4 – 10 days. Once hatched, they begin feeding on the leaves of their host plant immediately. The larvae eat almost constantly for around 21 days, before dropping off the plant and burrowing into the soil to pupate.
The pupal stage of the Colorado potato beetle lasts for 5 – 10 days and takes place in the soil beneath their host plant.
Adult potato bugs may overwinter a few inches below the surface of the soil, before emerging in the Spring to feed, mate, and lay more eggs.
How to identify Colorado potato beetles
Colorado potato beetles are serious potato pests, and home-growers need to be on the lookout for these insects. The adult beetles have an oval shape and measure around 3/8 inches long. They have yellowish-orange wing covers decorated with a distinctive set of 10, narrow, black, vertical stripes.
The eggs of the potato bug are yellowish-orange, oval-shaped, and are usually laid on the underside of potato leaves. Finally, the larvae of the Colorado potato beetle are brick-red with black heads when they first hatch, though their color fades to pink as they mature. All Colorado potato beetle larvae also have two rows of black spots on either side of their bodies.
Colorado potato beetles vs. false potato beetles
Colorado potato beetles are often confused with false potato beetles. Although these beetle species look similar, the false potato beetle is not a pest, whereas the Colorado potato beetle most certainly is.
The easiest way to tell them apart is by the color of their wing-covers. Whereas the Colorado potato beetle is yellowish-orange with black stripes, the false potato beetle is white and black. The false potato beetle is also less widespread than the Colorado potato beetle, and is found primarily in Eastern states including Texas, Florida, Missouri, Illinois, Indiana, Maryland, West Virginia, and Virginia.
Colorado potato beetles vs. striped cucumber beetles
Another insect that is often mistaken for the Colorado potato beetle is the striped cucumber beetle. Both of these insects have yellowish bodies with black stripes, which can make it easy to get them confused. However, cucumber beetles have brighter yellow bodies than Colorado potato beetles, and only three black stripes (whereas Colorado potato beetles have 10).
Unfortunately, striped Cucumber beetles can be as bad for your garden as potato bugs, as they feed on a wide range of host plants.
They are usually found on cucumbers, squash, melons, and other related plants, where they feast on the blossoms, roots, stems, and leaves, depending on their life stage. They also carry a bacteria that causes bacterial wilt, and which may be transmitted to host plants.
Colorado potato beetles (AKA potato bugs) are a serious insect pest of potato plants. These bugs are thought to have originated in central Mexico, and have since spread throughout most states of North America.
Adult Colorado potato beetles can be identified by their yellow-orange and black stripes, and their larvae by their brick-red coloring and twin rows of black dots. Potato bugs can cause severe damage to potato plants by feeding on the leaves, leading to severely reduced crop yield and even early plant death.