Flea Beetle: All You Need to Know for a Pest-Free Garden

Flea beetles are a subfamily of leaf beetles known for their distinct jumping abilities. These tiny pests can cause significant damage to various plants, including vegetables and ornamental plants. As gardeners and farmers seek solutions for controlling these insects, understanding the biology, behavior, and damage caused by flea beetles is essential.

Different species of flea beetles come in a range of colors, such as shiny black or brown, with some having white or yellow stripes. Typically, they measure around 1/10″ in size, with the exception of the spinach flea beetle, which grows up to 1/4″ long. The presence of these beetles can be identified through the small holes they leave on the leaves of affected plants, known as “shotholes.”

Preventive measures, such as covering plants with row covers or using insecticides containing permethrin, can help control flea beetle infestations. However, it’s crucial to consult with a professional or local extension office to determine the best course of action based on the specific beetle species and the types of plants being affected.

Identifying Flea Beetles

Appearance

Flea beetles are small insects that can cause damage to plants by feeding on their leaves. They have enlarged hind legs, allowing them to jump long distances when disturbed. Most adult flea beetles are very small, ranging from 1/16 to 1/8-inch long1.

Colors

Flea beetles can be found in a variety of colors, including:

  • Black
  • Bronze
  • Bluish
  • Brown to metallic gray

Some species also have stripes1.

Types of Flea Beetles

There are several types of flea beetles, including:

Striped Flea Beetle

  • Scientific name: Phyllotreta striolata
  • Stripes: Present
  • Typical damage: Shotholes on leaves2

Spotted Flea Beetle

  • Scientific name: Epitrix cucumeris
  • Stripes: Absent, has spots
  • Typical damage: Flecking on leaves3

Solid Flea Beetle

  • Scientific name: Phyllotreta cruciferae
  • Stripes: Absent, solid color
  • Typical damage: Flecking on leaves3
Type Scientific Name Stripes Damage
Striped Flea Beetle Phyllotreta striolata Present Shotholes
Spotted Flea Beetle Epitrix cucumeris Absent Flecking
Solid Flea Beetle Phyllotreta cruciferae Absent Flecking

In order to identify flea beetles and determine the best method to get rid of them, it’s essential to know their appearance and habits. For example, the Western Black Flea Beetle feeds on leafy spurge, a serious invasive weed4.

Life Cycle and Biology

Overwintering

Flea beetles overwinter as adults in leaf litter or other debris. They become active and start feeding on plants when the weather warms up in spring.

Weather factors:

  • Warm temperatures
  • Adequate moisture

Eggs and Larvae

After emerging from overwintering, adult flea beetles lay their eggs in the soil near host plants. Once the eggs hatch, the larvae feed on plant roots and underground stems. Some common host plants for flea beetle larvae include:

  • Lettuce
  • Spinach
  • Flower seedlings

The larvae eventually pupate in the soil and acquire their characteristic jumping ability when transforming into adults.

Adult Flea Beetles

Adult flea beetles are tiny insects measuring from 1/16 to 1/8 inch long, depending on the species. They have large hind legs which can be used for jumping from plant to plant. Their coloration may vary from black, bronze, or bluish to metallic gray, and some species may have stripes on their bodies.

Characteristics:

  • Small size
  • Jumping ability
  • Variable coloration

Comparison of Flea Beetle Species

Species Size Color
Crucifer Flea Beetle 1/10 – 1/5 inch Black or bronze
Eggplant Flea Beetle 1/10 – 1/5 inch Shiny black or brown
Spinach Flea Beetle 1/4-inch Iridescent blue-green

Pros of Flea Beetles:

  • Can help control weeds by feeding on them

Cons of Flea Beetles:

  • Damage seedlings and adult plants by feeding on leaves
  • Can transmit plant diseases

Adult flea beetles may cause extensive damage to various plant species, but they can be managed using a combination of cultural, physical, biological, and chemical control methods.

Flea Beetle Damage and Host Plants

Vegetable and Ornamental Plants Affected

Flea beetles are tiny insects notorious for causing damage to a variety of vegetable and ornamental plants. Some common vegetable plants targeted by flea beetles include:

  • Radishes
  • Lettuce
  • Spinach
  • Leafy greens
  • Solanaceae (e.g., tomatoes, eggplants, potatoes)
  • Brassicaceae (e.g., cabbage, broccoli, kale, Brussels sprouts)

In addition, flea beetles can also feast on ornamental plants such as nasturtiums. Different types of flea beetles might be responsible for infestations, including Phyllotreta and Psylliodes species.

Timing and Signs of Damage

Flea beetles can cause damage during all stages of plant growth. However, young plants and seedlings are particularly vulnerable. Established plants can usually withstand flea beetle damage, but might still experience reduced growth and yield.

Signs of flea beetle damage usually appear as tiny, round holes in foliage, often referred to as “shotholes”. Here’s a comparison of flea beetle-inflicted damage on various plants:

Plant Damage Type Flea Beetle Species
Potato Holes in leaves Potato flea beetle
Spinach Large holes or notches Spinach flea beetle
Leafy greens Shotholes in foliage Various species

In severe cases, flea beetles can transmit diseases like bacterial blight or wilt, compounding the potential damage to plants. Early detection and management can help mitigate the damage caused by flea beetle infestations on garden plants.

Flea Beetle Control and Prevention

Physical Controls

  • Row covers: Use lightweight floating row covers to protect plants, especially during the flea beetle’s most active stage, which is late spring and early summer. Remove them once the plants are established.
  • Sticky traps: Place yellow sticky traps along the edges of your garden to catch flea beetles before they can reach your plants.

Organic Methods

Preventing flea beetles starts by understanding their life cycle. Organic flea beetle control includes:

  • Diatomaceous earth: Apply food-grade diatomaceous earth around the base of plants and on foliage where flea beetles congregate.
  • Neem oil: Spray a diluted neem oil solution on plant foliage, focusing on undersides where beetles lay eggs.

Chemical Control

Utilize chemical control as a last resort, and always follow label instructions. Examples of chemical control include:

  • Insecticides: Apply contact insecticides to plants when flea beetles are present. Keep in mind that chemical methods pose risks to beneficial insects as well.
  • Systemic pesticides: They may help in controlling certain flea beetle species like Phyllotreta cruciferae and Systena blanda. But be cautious, as they may cause harm to non-target organisms.

Companion Planting

Planting certain crops and plants near each other can have a positive impact on pest control. Here are a few examples of companion planting to deter flea beetles:

  • Trap crops: Planting less valuable plants, such as radishes, as a sacrificial trap crop can draw flea beetles away from your main crop and help manage populations.
  • Mint: Mint plants can repel various flea beetle species, including the eggplant flea beetle and crucifer flea beetle. However, mint may become invasive, so plant it in a contained area.
Control Methods Pros Cons
Physical (row covers, sticky traps) Non-toxic May require regular maintenance
Organic (diatomaceous earth, neem) Safe for humans and beneficial insects Less effective than chemicals
Chemical (insecticides) Fast results Harmful to beneficial insects and the environment
Companion Planting Easy, eco-friendly approach Does not offer 100% protection

Beneficial Insects and Natural Enemies

Flea beetles can cause damage to crops, but there are beneficial insects and natural enemies that help control their population.

  • For example, catnip is a repellent plant that can deter flea beetles away from your garden.

The following insects are considered natural enemies of flea beetles:

  • Tachinid flies: These flies are parasitic and lay their eggs on flea beetles, and their larvae consume the host beetles.
  • Braconid wasps: They also attack flea beetles with their sting, laying eggs within the beetle and when the larvae hatch, they feed on the host beetle.

Other predators of flea beetles are:

  • Birds: They feed on flea beetles, providing natural population control.
  • Parasitic insects: A variety of insects can serve as natural enemies, such as lady beetles and predatory gall wasps. These insects feast on flea beetles.

A good way to compare the beneficial insects is to create a table summarizing their features:

Insect Hosts Attacked Type of Control
Tachinid Flies Flea Beetles Parasitic
Braconid Wasps Flea Beetles Parasitic
Lady Beetles Flea Beetles Predator
Predatory Gall Wasps Flea Beetles Predator

In conclusion, several beneficial insects and natural enemies can help control flea beetle populations in your garden. Don’t forget to use repelling plants like catnip and allow the natural predators to play their role. A balanced ecosystem keeps flea beetles in check.

Footnotes

  1. (https://extension.umn.edu/yard-and-garden-insects/flea-beetles) 2

  2. (https://extension.usu.edu/pests/research/flea-beetles-vegetables)

  3. (https://extension.umd.edu/resource/flea-beetles-vegetables) 2

  4. (https://extension.colostate.edu/topic-areas/insects/flea-beetles-5-592/)

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Sumac Flea Beetle

 

Subject: Striped beetle
Location: Old Saybrook, CT
May 13, 2016 9:20 am
This was found in May in coastal Connecticut, in our school’s outdoor space. We’d like to know what it is.
Signature: The Willow Class

Sumac Flea Beetle
Sumac Flea Beetle

Dear Willow Class,
We quickly identified your Leaf Beetle in the family Chrysomelidae as a highly variable Sumac Flea Beetle,
Blepharida rhois, thanks to this BugGuide image.  According to BugGuide, it is also known as a Currant Flea Beetle. 

Letter 2 – Tumbling Flower Beetle

 

Subject: What’s that bug
Location: Columbus, OH
June 18, 2016 10:01 pm
Thank you for taking your time. I have a found a few bugs in my house and just want a professionals opinion on what they are. We both work in healthcare so bedbugs are a widespread concern.
Signature: Thank you, James

Unknown Beetle
Tumbling Flower Beetle

Dear James,
This is NOT a Bedbug, but we are not certain of its actual identity.  We presume it is very tiny.  We believe it is a beetle, and its long hind legs are quite curious.  Does it jump?  Our best guess is that it might be a Tumbling Flower Beetle in the family Mordellidae, and it looks the most like members of the Tribe Conaliini that are pictured on BugGuide.  It might also be a Flea Beetle with it most resembling the members of the Longitarsus Genus Group on BugGuide.  Why either of those two possibilities would be found in the home is most puzzling, which makes us speculate that this is either a small wood boring beetle or some species of food infesting beetle.  We will try to get Eric Eaton’s opinion.

Unknown Beetle
Tumbling Flower Beetle

Eric Eaton confirms Tumbling Flower Beetle
Daniel:
It is a tumbling flower beetle.  It could have flown into the house (they fly very well), or maybe come indoors on cut flowers or some other object.
Eric

Thank you for your quick reply. I assumed it was not a bed bug but would rather be safe than sorry. I then thought it was a flea from its hind legs, but I saw what looks like wings (or maybe just a split like a beetle on its back). They are tearing down a large forest near our house and have since gotten many different critters, bugs and snakes. Not to mention we have always been fighting lady bugs (or German beetles).
We have very little of a garden and if the only concern is flowers than I won’t treat. I guess my main concern is if it needs to be treated in regards to humans as I do have four kids.
They are very tiny. About the size of an adult flea. Which caused me concern as I do not look forward to treating for fleas. So I am hoping you can rule those out.
If there is anything I can do to help identify them, please let me know as you are doing me a huge favor.
James

Unknown Beetle
Tumbling Flower Beetle

Hi again James.
This is NOT a Flea.  Eric Eaton has confirmed that it is a Tumbling Flower Beetle, an outdoor species that somehow wandered into your home.

Letter 3 – Unknown Flea Beetle from Mount Rainier

 

Subject: Beetle ID
Location: Mt Rainier NP, WA
June 6, 2017 9:08 am
Team Biota, volunteers at Mt Rainier would like you to identify a recent find from Steven’s Canyon in Mt Rainier. The beetle was crawling along the rocks in the canyon (70 degrees, sunny) but, did not appear feeding on any plant life. Have never seen this beetle in the Park before.
Signature: J. Dreimiller

Unknown Flea Beetle

Dear J. Dreimiller,
This looks to us like a Flea Beetle in the genus
Disonycha, which is well represented on BugGuide, however, BugGuide data does not list any species as being reported in Washington or indeed, the entire Pacific Northwest.  At any rate, the best we can provide at this time is that this is a Leaf Beetle in the family Chrysomelidae.  There are no Leaf Beetles reported on the Mount Rainier National Park Check List, so perhaps you should post your images there to see if you can get a more specific identification.  Please let us know if you learn anything, and perhaps one of our readers will provide a comment with an identification.

Unknown Flea Beetle

Letter 4 – What's That Flea???

 

Subject: What Kind of Flea is This?
Location: Ontario Canada
January 22, 2013 11:45 am
Hi, we’ve had a flea issue lately although our cats do not go outside. My cats have been given advantage twice since December 15th and I vacuum almost every day. I’ve been unsuccessful at finding fleas on them. But it seems like we have two different kinds of fleas going on.
I’ve found a few on chairs that jump and appear to be cat fleas. They are small and dark brown and are very fast.
But every now and then I will get a bite and take my shirt or pants off and find a litter brown flea that doesn’t crawl as fast and doesn’t jump away when I try to catch it! Very disgusting to find a flea in your pants! I inspects my clothes every time I put them on and don’t see any on our beds. I wear white socks and never do I have any on them. It’s not like they are jumping all over us but every now and then there’s one biting me or my son but not my husband!
Could this be a squirrel flea?
Signature: Ali

Flea

Dear Ali,
We apologize.  Despite your excellent photomicroscopy, we haven’t the necessary skills to properly identify your Flea to differentiate it from other Fleas.  Perhaps one of our readers will be able to assist in this matter.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

4 thoughts on “Flea Beetle: All You Need to Know for a Pest-Free Garden”

  1. Does your bites hurt. I was having a problem with something biting me while I would set still or go to sleep I could not never see what was biting me . I had a allergic reaction to the bite very painful it would swell & itch like crazy.

    Reply
    • April that is exactly what I have! It’s driving me freakin nuts! I’m scaring from the bites it’s terrible and 4 Dermatolagists and 3 drs at local places have no idea what is causing the bites. How did you get rid of them???????

      Reply

Leave a Comment