Squash Lady Beetle: Essential Facts Uncovered

Squash lady beetles, also known as Epilachna borealis, are a common vegetable pest in the eastern United States, with a strong preference for cucurbits – plants of the gourd or squash family, which includes melons, pumpkins, squash, and cucumbers. Many gardeners may not realize that these beetles are actually a type of ladybug, though they are far from beneficial like their more well-known relatives.

As you tackle issues with these pests in your own garden, it’s essential to recognize their lifecycle and how they impact your plants. Squash lady beetles lay their eggs on the underside of leaves, which hatch after 1-2 weeks into nymphs. These nymphs have black heads and legs with light green bodies, eventually turning light gray as they become adults. Understanding the signs of an infestation can help you act quickly to protect your crops.

In this article, we will take a closer look at the damage caused by squash lady beetles, effective control methods, and how to prevent them from returning in the future. With this knowledge, you’ll be prepared to maintain a healthy, thriving garden, despite the presence of these pesky insects.

Understanding the Squash Lady Beetle

The squash lady beetle, also known as the squash beetle or squash ladybird beetle, is an insect posing a threat to the cucurbit family of plants, such as squash, melons, and cucumbers. When you are dealing with this pest, it’s essential to understand its characteristics and habits to protect your garden effectively.

Adult squash lady beetles are yellow or orange and have a dome-shaped body, similar to other lady beetles. They feature seven large black spots on each wing covering, along with four black spots on their thorax (middle body part)1. These insects can cause damage to the leaves, reducing your overall plant health and yield.

Keep an eye out for the signs of their presence. The eggs of squash lady beetles hatch in about one to two weeks, usually during mid-May to mid-June1. The newly hatched nymphs have a black head and legs with light green bodies. As they grow, their bodies turn light gray, eventually becoming brownish-black adults around 5/8 inches long2. It takes approximately five weeks for these insects to complete their lifecycle, from egg to adult2.

Some features of squash lady beetles to remember are:

  • Preference for cucurbits
  • Yellow or orange, dome-shaped bodies
  • Seven large black spots on each wing covering
  • Four black spots on their thorax
  • Lifecycle of approximately five weeks

By recognizing these characteristics, you can take prompt action if you spot squash lady beetles in your garden. Keep your plants healthy and protected by monitoring their population and implementing suitable pest management strategies when necessary.

Physical Description

Color and Spots

The Squash Lady Beetle, also known as Epilachna borealis, has a characteristic appearance. It is predominantly yellow or orange with a series of black spots.

  • Yellow or orange body
  • Black spots on the elytra (wing covers)

Other Defining Characteristics

Apart from their distinctive color, Squash Lady Beetles have unique features that set them apart from other ladybird beetles.

  • Thorax covered with black spines
  • An elongated, oval-shaped body

The Varieties

There are two main types of Squash Lady Beetles – Epilachna borealis and Epilachna varivestis. The latter is commonly known as the Mexican Bean Beetle, and they are both part of the Epilachna genus.

Feature Epilachna borealis Epilachna varivestis
Habitat Eastern US Widespread
Host Cucurbits Beans
Color Yellow/orange Yellow/orange

Identification Guide

Identifying Squash Lady Beetles can be challenging, especially when comparing them to native lady beetles and other similar insects. Here are some tips for distinguishing Squash Lady Beetles from their relatives:

  • Look for the black spots on their yellow or orange body
  • Check for the thorax covered with black spines
  • Observe their elongated, oval-shaped body

By considering these characteristics and comparing them to their relatives, you can accurately identify Squash Lady Beetles in your garden or environment.

Life Cycle

The Egg

In the life of a squash lady beetle (Epilachna borealis), the first stage is the egg. They lay their eggs in your garden, typically in July. These eggs are usually found on cucurbit crops, such as squash plants. Keep an eye out for these eggs, as they will hatch into the next stage of the life cycle.

The Larva Stage

After the eggs hatch, you’ll see lady beetle larvae, which will feed on your plants. These larvae are yellow or light green in color with black heads and legs. The larva stage lasts for about 1-2 weeks, during which they continue to feed and grow before transitioning into the pupa stage.

The Pupa Stage

In the pupa stage, the squash lady beetle larvae undergo metamorphosis to become adults. This stage generally takes place on the plants or nearby soil. After a brief period of time, the adult beetles will emerge, signaling the end of the pupa stage.

The Adult Stage

Upon reaching the adult stage, the squash lady beetles are yellow or yellow-orange with black spots and resemble common ladybug beetles. They feed on your vegetable plants, especially cucurbits like squash and pumpkin. Adults overwinter near field edges and make their way back to the crops in late June to feed and start the process of laying eggs for a new generation of squash lady beetles.

By understanding each stage of the squash lady beetle lifecycle and keeping it short and simple, you can better monitor and manage these common pests in your garden. Remember to take appropriate measures to prevent their infestation and further damage to your plants.

Feeding Habits

Preferred Plants

The Squash Lady Beetle, scientifically known as Epilachna borealis, is a type of ladybug that has a strong preference for plants in the squash family, called cucurbits. Examples of these plants include:

  • Squash
  • Zucchini
  • Gourd
  • Melons
  • Cucumbers

These beetles are particularly attracted to cucurbits, but you might also find them feeding on bean leaves as well.

Feeding Impact on Plants

Squash Lady Beetles cause damage primarily by feeding on the tissue between the veins of leaves. This feeding habit can lead to:

  • Scraping or “windowpaning”
  • Reduced plant growth
  • Decreased fruit quality

These damages may affect the overall health and productivity of your cucurbit crops.

To protect your plants from Squash Lady Beetle damage, it’s important to know their feeding preferences and monitor your garden for any signs of potential infestations.

Distribution and Habitat

The Squash Lady Beetle, scientifically known as Epilachna borealis, is primarily found in the eastern United States. This insect is native to North America, with a significant presence along the Atlantic Coast.

These beetles have a strong preference for cucurbit plants, which include melons, pumpkins, squash, and cucumbers. They typically make their home in vegetable gardens and farms where these plants are grown. Enjoying temperate climates, the Squash Lady Beetle thrives in the eastern United States, where most of its preferred habitat can be found.

So, when you’re tending to your vegetable garden, be on the lookout for these small, yellow or orange insects. They might be hard to spot at first due to their round, dome-shaped bodies that resemble ladybugs. However, upon closer inspection, you will notice the distinguishing feature of seven large black spots on each wing covering and four black spots on their thorax.

Remember, while the Squash Lady Beetle is prevalent in the eastern United States, it is not exclusive to this area. Gardeners and farmers in other parts of North America should also keep an eye out for this pest as it could affect your cucurbit plants. Being aware of its distribution and habitat will help you in your efforts to manage and prevent an infestation.

Role in the Ecosystem

The Squash Lady Beetle, also known as Epilachna borealis, plays a unique role in the ecosystem. Predominantly found in the eastern United States particularly along the Atlantic Coast, they’re distinct from other ladybugs because they prefer to feast on plants rather than insects.

You might find these beetles munching on the leaves of your cucurbits – a family of plants that includes melons, pumpkins, squashes, and cucumbers. They can cause noticeable damage to your plants, such as small yellow-green or white spots on leaves, and may even reduce yields by sipping plant sap.

While Squash Lady Beetles may not be the most beneficial insects for gardeners, they do have a place in the ecosystem’s food chain. They serve as prey to other predator insects and animals that help control their population.

Most importantly, Squash Lady Beetles help differentiate the good from the bad, as many ladybugs are valuable allies in the fight against garden pests like aphids. So remember, before you start treating your garden to control these beetles, take a moment to appreciate their role in the ecosystem and ensure you aren’t harming beneficial insects in the process.

Control and Prevention

Natural Methods

One way to control and prevent squash lady beetle infestations is by attracting beneficial insects to your garden. These insects, such as lady beetles and predators, can help keep the population of squash lady beetles in check. For example, you can plant flowers that attract beneficial insects like:

  • Yarrow
  • Dill
  • Fennel

Home Remedies

Another method for controlling squash lady beetles is using soapy water. Mix a few drops of dish soap with a quart of water. Next, spray the solution on the affected plants, particularly the underside of leaves where the beetles and their eggs are often found. This simple home remedy helps to eliminate the beetles without causing harm to your cucurbit crops.

Cultural Practices

Implementing good cultural practices in your garden can also help prevent squash lady beetle infestations. Here are a few tips you can follow:

  • Regularly inspect your garden for signs of infestation.
  • Remove and dispose of plant debris promptly.
  • Rotate your crops each gardening season.

By following these methods, you can help protect your cucurbits from squash lady beetles and maintain a healthy garden. Remember, prevention is key when it comes to managing garden pests.

Conclusion

In your gardening journey, you might encounter the Squash Lady Beetle, a common vegetable pest found in the eastern US. These beetles prefer plants of the gourd or squash family, including melons, pumpkins, squash, and cucumbers.

When dealing with the Squash Lady Beetle, remember to monitor your plants closely during the harvest season. As a nuisance to gardeners, they can damage your plants, reduce their growth, and decrease yield.

To manage and control Squash Lady Beetle populations, it’s helpful to employ the following practices:

  • Regularly inspect your plants for signs of infestation.
  • Remove any eggs or beetles you find by hand.
  • Use organic pest control methods, such as introducing beneficial insects that prey on Squash Lady Beetles.

By taking these steps, you can maintain the health of your garden and enjoy a bountiful harvest without the negative effects of Squash Lady Beetles. Keep up the good work, and happy gardening!

Footnotes

  1. Troublesome lady beetles: Mexican bean and squash beetles 2

  2. Lookout for Squash Bugs | Extension Marketing and Communications 2

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 – Metamorphosis of a Squash Ladybird Beetle

 

mystery solved! before and after photos…
These are all over my squash plant in North Carolina!
Joann

Hi Joann,
We weren’t really familiar with the larvae of the Squash Ladybird Beetle, Epilachna borealis, but thanks to your photos, now we are. Most Ladybird Beetles are predatory, but this particular species feeds on the leaves of squash and pumpkin plants in both larval and adult form.

Letter 2 – Squash Ladybird Beetle

 

Is this eating my squash?
The squash in my garden were not looking too good, then I discovered a orange and black spotted bugs that looked kind of like Ladybirds. I told one of the ladies at the nursery about my squash getting eaten and about the orange and black spotted bug, and she confirmed they were Ladybugs and not to put insecticide on the plants but let the good bugs do the work. HA!! Now whatever is eating my squash was going to get it. However my squash keep looking worse and worse even with the appearance of more and more Ladybird Bugs. I find these bugs on healthy leaves, then check back a few hours later and the leaves are all torn up. Could they be what is eating my squash!?! Are these wolves in sheep’s clothing?!? HELP!!!
Bard Letsinger
Victoria,Texas (110 miles south of Houston along the coast)

Hi Bard,
You are correct, this is a Squash Ladybird Beetle, Epilachna borealis. This species and its close relative, the Mexican Bean Beetle, Epilachna varivestis, are rarities among the Ladybird Beetles which are otherwise carniverous. You can view other images of BugGuide, which indicates the range of this species as “Scattered distribution over the eastern half of th U.S. south of Massachusetts.”

Letter 3 – Metamorphosis of a Squash Ladybird Beetle

 

mystery solved! before and after photos…
These are all over my squash plant in North Carolina!
Joann

Hi Joann,
We weren’t really familiar with the larvae of the Squash Ladybird Beetle, Epilachna borealis, but thanks to your photos, now we are. Most Ladybird Beetles are predatory, but this particular species feeds on the leaves of squash and pumpkin plants in both larval and adult form.

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.

  • 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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