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Kidadl Team

AUGUST 06, 2021

19 Spotted Cucumber Beetle Facts You’ll Never Forget

Spotted cucumber beetle facts include that they can infect plants with a bacterial disease.

The spotted cucumber beetle or Diabrotica undecimpunctata is an agricultural pest commonly found in North America. Also known as the southern corn rootworm, it can cause serious beetle feeding damage to field crops. This is also the reason why these beetles are a major agricultural concern. These insects are expensive and difficult to control because of their larvae’ subterranean nature. Three subspecies of these beetles are Diabrotica undecimpunctata howardi (spotted cucumber beetle or southern corn rootworm), Diabrotica undecimpunctata tenella (western cucumber beetle), and Diabrotica undecimpunctata undecimpunctata (western spotted cucumber beetle).

Western spotted cucumber beetles are native insects located throughout North America – the United States, Mexico, and Canada. Beetles cucumber are most destructive and abundant in the southern regions. However, these beetles don’t cause any trouble in sandy soils. It is one of two species that cause a lot of problems in the North American cucurbit plants. The other species is the striped cucumber beetle. It is easy to tell the adult of these two species apart. The southern corn rootworm is larger and has dark black spots on its back whereas the striped cucumber beetle is known to have long black stripes.

You can also check out our fact files on longhorn beetle and dung beetle from Kidadl.

Spotted Cucumber Beetle Interesting Facts

What type of animal is a spotted cucumber beetle?

The spotted cucumber beetle, Diabrotica undecimpunctata, is a type of beetle that is either orangish-green or yellowish-green in color and has 12 black spots on its back. They also can reach a length of about 0.25 in (6.4 mm) long. This species becomes active between dusk and dawn.

What class of animal does a spotted cucumber beetle belong to?

The corn rootworm belongs to the Insecta class and is found across the United States, Mexico, and Canada. It is one of the two species that are known to create havoc and damage trap crops. The other species is the striped cucumber beetle (Acalymma vittatum). Both species (spotted and striped cucumber beetles) primarily feed on roots, leaves, fruits, and flowers of cucurbit crops such as cucumbers, pumpkins, melons, and squash. Alternate host plants include peanuts, potatoes, corn, and beans of spotted and striped cucumber beetles.

How many spotted cucumber beetles are there in the world?

The accurate number of these beetles in the world is not available.

Where does a spotted cucumber beetle live?

The Diabrotica undecimpunctata belongs to the Chrysomelidae family. This is a common agricultural pest insect that can be found easily on the east of the Rocky Mountains. Its closely related species can be found throughout the United States.

What is a spotted cucumber beetle's habitat?

A southern corn rootworm's habitat is usually agricultural land where it can find a host cucurbits plant to feed on.

Who do spotted cucumber beetles live with?

There is not much information available regarding who these beetles live with.

How long does a spotted cucumber beetle live?

One spotted cucumber beetle's life cycle is about 6 to 9 weeks long. They can pass through 2 or even a partial third generation per year.

How do they reproduce?

Unmated adults spotted or striped cucumber beetles overwinter under debris around buildings and leaves. This beetle steps out of its hiding sites during late March. Females lay four eggs per day and about 125 eggs in a lifetime. Female beetles oviposit or lay eggs between late April and early June. Once the eggs hatch, the larvae feed on roots present in the soil. They take somewhere between two and four weeks to mature before pupating. Their immature stages, where the larvae feed on the roots and stem base in the soil, can cause cucurbits plant damage. The first generation of adult beetle will emerge between late June and early July. In most cases, there are two generations of adult beetle per year from females that lay eggs. However, there has been a report of a single generation of adult beetles in the city of Oregon. Three have been reported in Alabama and southern California. It takes them somewhere between six and nine weeks to finish one life cycle. A 12-spotted spotted cucumber beetle is known to pass two or a partial third generation.

What is their conservation status?

No information regarding their conservation status is available at the moment.

Spotted Cucumber Beetle Fun Facts

What do spotted cucumber beetles look like?

Mature cucumber beetle larvae are about 0.47 in (12 mm) long and look like worms. Their body is white and slender and they have three pairs of brown, long legs. They also have a brown-colored head capsule that measures 0.3 in (8 mm) the first instar, 0.4 in (10 mm) the second, and 0.6 in (15 mm) the third. The cucumber beetle larvae's last segment’s dorsal side has a dark brown-colored plate. It takes the larvae seven, five, and four days to develop first, second, and third instar respectively. The complete larval development takes about two to three weeks. In the last stage, the larva builds a chamber inside the soil to pupate within it.

The next stage is the pupae where they are initially white but with age, they turn yellowish and start to look like an adult. They are about 0.18 in (4.5 mm) wide and 0.3 in (7.5 mm) long. At the tip of their abdomen, there is a pair of stout spines. Other abdominal segments’ dorsal side consists of smaller pines. The pupal period can vary between 6 to 10 days.

The next stage is the adult beetle. They are yellow-green in color, have 12 black spots on their forewings or elytra, and are 0.25 in (6.4 mm) long. They have black hands and legs and their beaded black antennae are about 0.06 in (1.6 mm) long.

Spotted cucumber beetles have 12 spots on their back.

How cute are they?

With their colorful appearance, some might consider the spotted or striped cucumber beetles cute.

How do they communicate?

Not enough information is available regarding their means of communication.

How big is a spotted cucumber beetle?

It is about 0.25 in (6.4 mm) long and its beaded black antenna are 0.06 in (1.6 mm) long.

How fast can a spotted cucumber beetle move?

Not enough information is available regarding its speed.

How much does a spotted cucumber beetle weigh?

Not much information is available regarding its weight.

What are the male and female names of the species?

Not enough information is available regarding the male and female names of this species.

What would you call a baby spotted cucumber beetle?

Babies are called larvae. The larvae feed on roots present in the soil. Compared to the losses caused because of bacterial wilt disease, this damage is minimal.

What do they eat?

Adults feed on flowers, pollen, and foliage. Their feeding damage on melon rinds begins late in the season which can reduce market quality. The larvae of these insects, which become active between dusk and dawn, are known for feeding on stems and roots which damages them. Compared to the losses caused because of bacterial wilt disease, this damage is minimal.

Are they dangerous?

Adults spotted cucumber beetles are known to be nasty little pests that attack cucurbits plants like cucumbers, pumpkins, melons, and squash during the growing season by feeding on them. Also, this species causes bacterial wilt of cucurbit or trap crops by spreading it around and infecting plants, which then start to wilt and eventually die.

Would they make a good pet?

You should only get them as a pet if you are an expert in insects as their poisonous nature makes them difficult to take care of. When they bite you, a chemical substance is released causing your skin to blister. There won't be permanent damage, but a bite can cause a lot of pain.

Did you know…

Even though there are several similarities between spotted and striped cucumber beetles, Acalymma vittatum, there are a few differences. Adults are known for feeding on more than 200 crop and non-crop plants. Rarely do adults feed on any plant other than cucurbits. Also, the yellow or green spotted cucumber beetle seems to be a pest farther down the south in the US whereas the striped cucumber beetles, with the black stripes, are known to dominate farther north.

Striped cucumber beetles lay their eggs at the cucurbit plants’ base and then, the beetle larvae start feeding on the roots of these plants. They are very different in this case as they lay their eggs on corn and grasses so that the beetle larvae do not damage the cucurbit crops, the most popular plants for cucumber beetle feeding. After spotted and striped cucumber beetles eggs hatch, their larvae start feeding on the root tissue. You cannot just look at the aboveground foliage and see the obvious damage done by the larvae that are feeding on the plants by the adult beetles. You will have to pull up the plant and find resistance because of the roots being eaten by spotted or striped cucumber beetles. The larva will then pupate in the soil for a week before becoming adults.

How do you get rid of spotted cucumber beetles?

Here are quite a few ways to get rid of cucumber beetles. Regularly inspect the cucurbit plants that have been planted recently to check for the beetle, especially when the plants are seedlings. Catch pests like cucumber beetles with a yellow sticky trap. Knock them into the ground and place a piece of cardboard under the plant to catch them. You can also use a handheld vacuum for sucking up the beetles. It is hard to pick them by hand, but if you use yellow gloves that are coated in petroleum jelly, it will be much easier. Use row covers for covering seedlings. However, in order to allow for pollination, you will have to remove these covers during the blossoming time for multiple hours every day. There is a spotted cucumber beetle pesticide that you can use on cucurbit plants because of their highly sensitive nature. You will have to use them when plants have just started to emerge from the soil. According to The 1963 Old Farmer’s Almanac folk advice, wood ashes and nasturtiums are effective against them.

There are a few ways to prevent them from infecting your crops. By tilting your land or garden during late fall, you will be able to expose spotted cucumber beetles hiding there to the winter conditions and decrease the beetle populations. For spotted cucumber beetle control population, remove all the debris after the fall harvest. Rotate your crops so that cucurbit crops aren’t directly planted into the soils that contain cucumber beetles over winter populations. Instead of direct seeding, you can transplant young plants. This way, you will be able to protect the vulnerable seedlings from damage. Plant trap props like cucurbit varieties that are attractive to cucumber beetles at your harvested crops’ perimeter so that the beetle populations don’t migrate into the harvested crop. If they are an annual problem for you, let them come out of hiding and plant the seeds later. Adult beetles can find vulnerable seedlings. By the time your seeds are up and growing, the beetles will already be gone thinking that there are no cucumbers in your land. You can use natural enemies such as braconid wasps, soldier beetles, and some nematodes. Plant your cucurbits vegetables with flowers that can keep the pests away from your plants that you don’t want to get attacked by the beetles.

The bacterial wilt of cucurbits can cause a lot of damage to the cucurbits plants once they have been infected by the spotted or striped cucumber beetle. Because of the bacterial wilt, the leaves will turn brown and yellow at the margins, wither completely, and die. The bacterial wilt is caused when the bacteria overwinter in spotted or striped cucumber beetles. Managing spotted or striped cucumber beetle is the best way of controlling bacterial wilt. Once the plant has been infected by bacterial wilt from the spotted or striped cucumber beetle, pesticides won't be able to do anything. You have to catch the beetles using a yellow sticky trap or trap row covers in order to prevent bacterial wilt.

There is not a lot that can be done once the cucurbits plant gets bacterial wilt. In the case of bacterial wilt or cucurbits, the leaves will start drying up and the cucurbits plants will wilt and die.

How does the spotted cucumber beetle get its name?

Cucumber beetle is a name given to the genera of beetles that are known for feeding on cucurbits like cucumbers and other plants. These notorious pests of agricultural crops have spots on their backs and are, therefore, known as the spotted cucumber beetle.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other arthropods from our bombardier beetle facts or Christmas beetle facts pages.

You can even occupy yourself at home by coloring in one of our free printable Spotted cucumber beetles coloring pages.

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