Potato Beetle

The potato beetle goes by various names, including the potato bug, ten-lined potato beetle, and ten-striped spearman, and they are one of the worst potato pests on the planet. This bug is notorious for its ability to resist pesticides. In fact, they have become immune to 52 chemical compounds used in insecticides over the last 50 years, including cyanide. However, there are some populations that aren’t immune to all these chemicals. These beetles first originated in the southwest United States and northern Mexico. But they are presently found across North America, Asia, and Europe.

Potato Beetle Species, Types, and Scientific Name

The potato beetle’s scientific name is Leptinotarsa decemlineata, and they belong to the order Coleoptera, which contains over 250 000 species, making it the biggest order of Insecta. This order is generally distinguished by a pair of membranous hind wings, and pair of hardened front wings called elytra. In addition, they have slightly modified chewing mouthparts that serve various purposes and undergo a complete metamorphosis.

Potato beetles are members of the Chrysomelidae family, also known as leaf beetles. This family consists of around 37 000 species, over 2 500 genera.

Appearance: How To Identify the Potato Beetle

Potato beetles have a round shape with a yellowish-orange exoskeleton, striped with black lines on the wings, black spots behind the head, and two dark brown antennae on the head with uneven tips. Their bodies measure 0.39 inches from the head to the tip of the abdomen and are around 0.12 inches wide. Additionally, these beetles can weigh between 50 to 170mg. Lastly, potato beetles have three pairs of yellowish feet with dark brown or black tips.

Habitat: Where to Find the Potato Beetle

Potato beetles prefer to inhabit temperate and terrestrial suburban gardens, fields, and grasslands. While native to small areas in western North America, they have spread incredibly quickly to potato crops on other continents like Asia and Europe.

During winter, adult potato beetles will dig four to 12-inch tunnels in the ground of harvested potato fields, and once the weather starts to heat up, they will emerge, usually around May. Adult potato beetles do migrate, but not far distances. They will only travel several miles to find a solanaceous host. So, besides potatoes, these hosts include:

• Nightshades
• Tomatoes
• Peppers

Diet: What Does the Potato Beetle Eat?

Their name is derived from their primary food source, the potato plant. However, potato beetles also feed upon several other plants, like tobacco, tomato, pepper, and eggplant.

Life Cycle of the Potato Beetle

These beetles have a polygynandrous mating system where they choose multiple mates once breeding season starts. Their mating seasons usually kick off in May once the weather starts to warm up. This is when people will begin seeing infestations pop up in their crops or gardens. Adult potato beetles will only feed for a short period before mating. Female potato beetles usually lay their eggs underneath the host plant’s leaves, which shields them from the sun’s rays. These tiny beetles can deposit over 300 eggs within four to five weeks.

Eggs take around four to 10 days to hatch, depending on the latitude and temperature. Once they hatch, larvae will emerge with four instars that last for approximately 21 days. During this period, the larvae will feed off the host plant, only stopping while they molt. Then the larvae drop into the soil and develop a spherical cell where they morph into a yellow pupa. This phase generally lasts for five to 10 days. Potato beetles can have one to three generations every year.

Is the Potato Beetle Dangerous to Humans?

Potato beetles are not dangerous to humans, but they might be toxic to smaller animals as there are many species that won’t eat them.

How to Get Rid of the Potato Beetle

There are a few natural methods that will get rid of a potato beetle infestation. However, they will only work if you act fast to ensure the infestation doesn’t get larger. If you spring into action as soon as you see evidence, you have a much higher chance of saving your crops. Therefore, it’s best to illuminate potato bugs when they are in their egg or larval stage because 75% of the damage they cause happens before the larvae morph into adults.

Hand-Pick Beetles

If you see chewed or damaged leaves in your crops, this might be the first clue you have an infestation. Therefore, regularly check your potato leaves for larvae or eggs. Additionally, where there are adult beetles, there will be larvae as well. If the infestation isn’t too large, you can hand-pick the eggs, larvae, and adults from the plants and discard them in a bucket of soapy water which will kill them.

If you can’t find any evidence on the leaves, check the soil around the plants in the early mornings, as adult beetles will burrow into the ground at night and resurface in the morning.

Vacuum Cleaner

Not many people know this, but you can actually use a vacuum cleaner to suck potato beetle eggs, larvae, and adults off the plants. While there are specific bug vacuums available, a normal handheld vacuum will do the trick.

Deterrent Sprays

Deterrent sprays mainly work on eggs or larvae as the adults have a hard carapace that is tough to penetrate. There are several sprays that are officially categorized as organic and contain azadiractin or Spinosad. Azadiractin is an insecticide that was developed from fermenting natural soil organisms. However, this product only works on larvae. A more effective solution is Spinosad, but it needs to be applied every 10 to 14 days while the beetles are still in their larval stage.

Neem Oil

Neem oil is an organic gardener’s go-to pesticide because it is so effective. This oil is extracted from the seeds of a neem tree and contains several compounds usually found in commercial insecticides. How it works is it reduces insect feeding and interferes with their hormone systems., which stops them from reproducing. However, while this is considered an organic product, it does not mean it isn’t toxic to humans; it just means that it’s made from naturally occurring ingredients. But, Neem oil in a spray form is relatively safe, but some people may experience skin irritations when using this product, and it can cause digestive issues if ingested. The only way it will work is if the insect actually eats the treated plant.

BT

Bacillus thuringiensis var. tenebrionis or BT can work really well at eliminating potato beetle infestations if the insect is in its larval stage. Therefore, people have to find the eggs and dose them in BT for it to be effective. Bacillus thuringiensis var. tenebrionis is a soil bacteria that paralyzes certain insects’ digestive systems, which makes the larvae starve to death. However, there are several strains of BT, so be sure to ask which one works specifically for potato beetles.

Encourage Natural Predators

Natural predators of the potato beetle include ladybugs and stink bugs. By artificially introducing these bugs to your garden, you can reduce potato beetle infestations. However, these predators won’t be able to get rid of the whole population, but they do make a dent.

Another option is to entice birds to your garden with multiple bird feeders, housing, and birdbaths, as they like to prey on the larvae.

Up Next

• Types of Beetles
• Horned Beetle Facts
• Figeater Beetle Facts

1. Wikipedia, Available here: https://en.wikipedia.org/wiki/Colorado_potato_beetle
2. Crop Watch, Available here: https://cropwatch.unl.edu/potato/colo_potato_beetle#:~:text=Adults%20overwinter%20four%20to%2012,such%20as%20tomato%20and%20pepper.
3. University of Florida, Available here: https://entnemdept.ufl.edu/creatures/veg/leaf/potato_beetles.htm