Plants That Repel Cucumber Beetles: Your Ultimate Garden Defense Guide

Cucumber beetles are common pests that can wreak havoc on your vegetable garden, especially on cucurbit plants like cucumber, melon, and squash. Fortunately, there are several plants that can help repel these pesky beetles and protect your garden naturally.

One such plant is the Blue Hubbard squash, which has been found to be effective in controlling cucumber beetles in small gardens or farms when planted near the cucurbit crops. This is because Blue Hubbard squash attracts the beetles, drawing them away from your more vulnerable plants. Another helpful plant is marigold, which emits a strong odor that repels many garden pests, including cucumber beetles. Planting marigolds around the border of your garden can help protect your crops from these unwanted visitors.

In addition to planting repellant plants, implementing proper garden maintenance, such as removing plant debris and rotating your crops, can also deter cucumber beetles from invading your garden. So when planning your garden layout, consider incorporating these repelling plants to keep your cucurbit vegetables safe and thriving.

Understanding Cucumber Beetles

Striped Cucumber Beetle

Striped cucumber beetles (Acalymma vittatum) are small insects with yellow and black stripes. They are common pests of vine crops like cucumber, squash, pumpkin, and watermelon.

  • Features:

    • Yellow body with three black stripes
    • About 0.2 inches (5mm) long
    • Feed on roots, leaves, flowers, and fruit
  • Damage: They can cause severe damage to plants, impede pollination and reduce fruit set.

Spotted Cucumber Beetle

Spotted cucumber beetles (Diabrotica undecimpunctata) differ from their striped counterparts in appearance but pose similar threats.

  • Features:

    • Yellow-green body with black spots
    • About 0.25 inches (6mm) long
    • Feed on roots, stems, and fruit surfaces
  • Impact: They can also cause significant damage, particularly by their larvae feeding on roots and stem bases.

Comparison Table:

Striped Cucumber Beetle Spotted Cucumber Beetle
Appearance Yellow with black stripes Yellow-green with black spots
Size 0.2 inches (5mm) 0.25 inches (6mm)
Damage Roots, leaves, flowers, fruit Roots, stem base, fruit surface
Impact on pollination Interferes with pollination Interferes with pollination

Both striped and spotted cucumber beetles can be controlled using similar methods, such as kaolin clay applications and planting trap crops like Blue Hubbard squash. By understanding their characteristics and damage capabilities, you can better protect your cucurbit crops.

Preventing Cucumber Beetle Infestation

Companion Planting

  • Radish: Plant near cucurbits to deter beetles
  • Nasturtium: Its strong scent repels cucumber beetles
  • Tansy: Helps protect cucumbers and squash plants

Companion planting can help prevent beetle infestations. Plant radishes near susceptible crops like cucumbers and squash to deter beetles.

Cultural Practices

  • Avoid excessive tilling to prevent beetle habitat disruption
  • Maintain good soil health

Limiting soil disturbance can reduce beetle populations. Healthy soil supports natural predators that control cucumber beetles.

Physical Barriers

  • Use row covers to protect plants
  • Remove covers during pollination

Physical barriers such as row covers can prevent beetles from reaching plants. However, remove covers during pollination to ensure good fruit set.

Biological Controls

  • Nematodes: Beneficial nematodes target beetles
  • Trap crops: Use ornamentals or other plants to lure beetles away

Using biological controls like nematodes and trap crops can help manage beetle infestations without insecticides, making it ideal for home gardeners.

Plants That Repel Cucumber Beetles

Marigolds

  • Marigolds release a pungent smell that helps repel cucumber beetles.
  • They are known to attract beneficial insects such as ladybugs, which may eat the beetle’s larvae.

Nasturtiums

  • Nasturtiums are both repellant and trap crop for squash bugs and cucumber beetles.
  • Their colorful flowers are a visual attraction for the beetles, which get caught on the sticky leaves.

Tansy

  • Tansy is a natural pesticide for cucumber beetles.
  • The plant’s strong scent effectively repels the beetles, preventing them from laying eggs on nearby crops.

Sage

  • Sage is an excellent companion plant for cucurbits like cucumbers.
  • The herb’s scent keeps cucumber beetles away, and it may also help enhance the flavor of cucumbers.

Catnip

  • Catnip repels cucumber beetles with its strong aroma.
  • Another benefit of catnip is its ability to attract some beneficial insects like lacewings.

Radish

  • Radishes can deter cucumber beetles because of their strong, peppery scent.
  • They are also beneficial as they help loosen the soil, allowing better root growth for nearby plants.

Herbs

  • A variety of herbs, such as beans, dill, mint, and oregano, can play a role in repelling cucumber beetles.
  • Besides acting as a natural pesticide, these aromatic herbs can boost the flavor of your cucumbers.
Plant Pros Cons
Marigolds Attracts beneficial insects, repels beetles May reseed
Nasturtium Traps beetles, attractive Can become invasive
Tansy Natural pesticide, beetle repellant Toxic to humans, pets
Sage Repels beetles, flavor enhancer May need pruning
Catnip Repels beetles, attracts beneficial insects May attract cats
Radish Deters beetles, loosens soil Requires space
Herbs Repel beetles, improve flavor, organic pest control May require special care

By incorporating these plants into your garden, you can create an environment that doesn’t support cucumber beetles. These plants not only deter the pests but also offer additional benefits such as attracting beneficial insects and improving the flavor of your crops.

Integrated Pest Management Strategies

Trap Crops and Row Covers

Trap crops can help manage cucumber beetles by attracting them away from the main crop. For example, blue hubbard squash can be an effective trap crop for striped cucumber beetles. Row covers can also be used to prevent beetles from reaching the plants, but these should be removed during flowering to allow access for pollinators like bumblebees.

Beneficial Insects and Nematodes

Introducing beneficial insects and nematodes can help control cucumber beetles and their larvae. Some examples include:

  • Ladybugs: feed on aphids and other soft-bodied insects.
  • Green lacewings: eat aphids, mites, and beetle larvae.
  • Beneficial nematodes: attack beetle larvae in the soil.

Pro’s and Con’s of Beneficial Insects and Nematodes:

Pros Cons
Environmentally friendly May not control larger infestations
Can reduce pesticide use Requires proper conditions for survival
Targets specific pests Takes time to establish

Monitoring and Identifying Life Stages

Regularly monitoring your plants for cucumber beetles can help you identify their presence early on, allowing you to take action before an infestation becomes severe. Typical signs of cucumber beetle damage include:

  • Skeletonized leaves, where only the veins remain.
  • Stunted growth or yellowing of plants.
  • Holes in leaves and flowers.

When monitoring, pay close attention to the different life stages of the cucumber beetle to ensure effective control:

  1. Adults: striped or spotted, feed on leaves, flowers, and fruits.
  2. Larvae: found in soil, feed on plant roots and stems.

Using integrated pest management strategies, like trap crops, row covers, beneficial insects, and nematodes, as well as regular monitoring, can help keep cucumber beetle populations in check while minimizing damage to your plants and their antennae.

Managing Beetle-Caused Diseases and Wilt

Bacterial Wilt

Bacterial wilt is a disease affecting cucurbits like melons, pumpkins, and squash. It is transmitted by cucumber beetles feeding on the plants. To manage bacterial wilt:

  • Monitor cucumber beetle populations by scouting weekly
  • Consider treatment if at least 1/4 of plants have 2+ beetles1

Fusarium Wilt

Fusarium wilt is a soil-borne fungal disease impacting cucurbits. It causes wilting and eventually plant death. To manage fusarium wilt:

  • Practice crop rotation
  • Remove and destroy affected plants immediately

Mosaic Virus

Mosaic virus is a viral disease infecting cucurbits and causing deformed leaves, reduced yields, and fruit damage. It is spread by aphids. To manage mosaic virus:

  • Implement aphid control methods
  • Promote beneficial insects
  • Keep the garden weed-free

Comparison Table:

Disease Cause Symptoms Management
Bacterial Wilt Cucumber Beetles Wilting; yellowing leaves Monitor beetles; control their numbers
Fusarium Wilt Fungal Pathogen Wilting; plant death Crop rotation; remove affected plants
Mosaic Virus Viral Infection Deformed leaves; fruit damage Control aphids; promote healthy garden

Additional Tips for a Healthy Cucumber Garden

Cleaning Garden Debris

  • Removes hiding spots for pests
  • Reduces chances of overwintering beetles

Keeping your garden clean is a simple yet effective way to reduce cucumber beetle populations. Regularly remove all garden debris, such as fallen leaves and dead plant parts, to eliminate hiding spots where beetles may overwinter. For example, the asparagus beetle and Japanese beetles are known to overwinter in garden debris.

Proper Pollination

  • Allows greater fruit yield
  • Attracts beneficial pollinators

Ensuring proper pollination contributes to a healthy cucumber garden. Encourage pollinators, like bees, to visit by planting attractive flowering plants such as radishes. These plants not only promote healthy pollination but also help to deter pests like cucumber beetles. Penn State Extension highlights the importance of pollination in improving the size and weight of cucumbers.

Optimal Garden Layout

  • Makes use of companion plants
  • Enhances pest control

Strategically planning your garden layout is an effective way to deter pests. Consider planting companion plants that repel cucumber beetles near your cucumber seedlings, such as onions. Additionally, utilizing traps can help to monitor and manage beetle populations. By correctly spacing plants and considering companion planting, you can create a natural system of pest control in your garden.

Companion Plant Effect on Cucumber Beetles
Onions Deters pests by producing strong odor
Radishes Attracts pollinators and repels pests

Impact of Cucumber Beetle on Other Plants

Melons and Squash

Cucumber beetles are a significant threat to melons and squash. These pests feed on various plant parts, causing damage to roots, leaves, and flowers.

  • Melons: Cucumber beetles target watermelons and cantaloupes, interfering with pollination and reducing fruit set.
  • Squash: Both summer and winter squashes are affected, with the beetles spreading bacterial wilt and squash mosaic virus.

Tomatoes and Peppers

Cucumber beetles may also impact tomatoes and peppers, although not as severely as cucurbits.

  • Tomatoes: While not a preferred target, beetles may still cause some damage to tomato plants.
  • Peppers: Beetles can feed on pepper leaves but rarely cause significant damage.

While not the primary host, certain plants can repel cucumber beetles:

  • Carrots: Known to repel cucumber beetles if planted near cucurbits.
  • Garlic: A natural deterrent for many pests, including cucumber beetles.
  • Weeds: Some weeds, like catnip, may repel cucumber beetles with their scent.
Plant Impact on Cucumber Beetles Example
Melons High Watermelon
Squash High Summer Squash
Tomatoes Moderate-Low Beefsteak Tomato
Peppers Low Bell Pepper
Carrots Repellant N/A
Garlic Repellant N/A
Weeds Repellant Catnip

Footnotes

  1. UMN Extension

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 – Twelve Spotted Cucumber Beetles might be repelled by radishes

 

Subject: Twelve-spotted cucumber beetle
Location: Naperville, IL
August 26, 2012 8:26 am
Hi Daniel~
These spotted cucumber beetles took up residence the first year I planted my vegetable garden and nearly defoliated every concurbit they came into contact with: cucumbers, naturally, watermelon, squash, canteloupe, as well as mammoth sunflowers. Then I read (on the internet, so it must be true :)) that inter-planting radishes will discourage their presence. The next spring, I may have gone a little wild and scattered radish seeds all over the garden, but sure enough, the radishes now self seed each year in acceptable numbers, and the cucumber beetles are just passing visitors. Other than my little anecdote, I have no idea if the two are related. All the best!
Signature: -Dori Eldridge

Twelve Spotted Cucumber Beetle

Hi Dori,
New gardeners are always writing to us wanting to know how to control garden pests.  We haven’t received many identification requests for Twelve Spotted Cucumber Beetles,
Diabrotica undecimpunctata, but we find your radish tip quite fascinating.  Your photos are also quite beautiful.

Twelve Spotted Cucumber Beetle

Thank you, Daniel.  Our small neighborhood borders on two sides what is now prairie preserve but used to be corn fields a few decades ago.  I have often wondered if the decline I have experienced in spotted cucumber beetles (Diabrotica undecimpunctata) was due to the radish trick (I looked again this morning, and by Googling the the key words, came up with quite a number of such tips) or simply the reverting to nature of the former corn fields, which I understand is a favored feeding ground of their larvae, aka corn rootworms.  I hope you have a successful start to your new semester.  All the best to you.

Hi Dori,
The demise of the corn fields is most likely a factor.

 

Letter 2 – Striped Cucumber Beetle

 

Subject: Yellow Striped Beetle
Location: Pennsylvania
July 20, 2013 3:28 pm
This bug is eating my cucumbers, beans, and radishes. It’s killing the leaves. I’ve been finding them on the leaves that are shriveling up with holes in them. What should I do?
Signature: Kim

Striped Cucumber Beetle
Striped Cucumber Beetles

Dear Kim,
You have an infestation of Striped Cucumber Beetles, Acalymma vittata.  According to BugGuide:  “The most important hosts, perhaps the only larval hosts, are Cucurbitaceae” so it is possible something else is eating the beans and radishes.  The University of Connecticut Integrated Pest Management website has helpful information on the control of the Striped Cucumber Beetle.

Striped Cucumber Beetle
Striped Cucumber Beetle

Letter 3 – Striped Cucumber Beetle

 

Subject:  Yellow and Black Beetle
Geographic location of the bug:  Montreal, QC, Canada
Date: 07/04/2019
Time: 10:41 AM EDT
Your letter to the bugman:  I found this yellow and black beetle-like bug standing right next to an open banana peel, and the banana was used to make a smoothie. I do not know if the bug came from the banana and if the banana was strangely coloured because I did not make the smoothie. The peel was quite ripe. I caught the bug and put it in a plastic transparent cup. What is the name of the bug and If the bug came from the banana and I drank the smoothie, will I be ok?
How you want your letter signed:  Michael

Striped Cucumber Beetle

Dear Michael,
This is a Striped Cucumber Beetle, and according to BugGuide:  “The most important hosts, perhaps the only larval hosts, are Cucurbitaceae.”  We don’t know why it was on the banana.

Letter 4 – Twelve Spot Cucumber Beetle

 

What are these?
There are two pictures attached. Each picture has a different creature. Please identify them for me.

This is a Twelve Spot Cucumber Beetle, Diabrotica undecimpunctata. It is a serious plant pest on cucumbers and squash.

Authors

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  • 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.

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  • 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.

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1 thought on “Plants That Repel Cucumber Beetles: Your Ultimate Garden Defense Guide”

  1. In Southwest Utah i have also observed adults and larvae of this beetle feasting on tomatillo (Physalis) and jimsonweed (Datura). They can destroy tomatillo plants in just a few days.

    Reply

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