Squash vine borer is a common pest that can devastate your squash plants, leaving them wilted and unhealthy. They burrow into the stems of your plants, interrupting the flow of water and nutrients. This destructive larval stage can seriously impact your garden’s squash production if not dealt with promptly.
One way to manage squash vine borer is to regularly scout your plants for signs of infestation, such as the presence of frass or entry holes. Removing the larvae by cutting the vine and covering the stem with soil can help prevent further damage. Another option is applying pesticides following proper instructions to protect your plants from these pests.
There are also preventative measures that can be taken to reduce the chances of a squash vine borer infestation. For example, using protective collars made from aluminum foil or small plastic cups can help deter the borers from laying eggs on your vines. Additionally, selecting more resistant squash varieties like butternut and cushaw can make it harder for the borers to thrive in your garden.
Understanding Squash Vine Borer
The squash vine borer (SVB) goes through one generation per year. Here is a brief overview of its life cycle:
- Adult moths lay eggs on stems.
- In 7-10 days, eggs hatch and larvae bore into the plant.
- Larvae feed inside the stem for about 4 weeks.
- Just after, they leave to pupate in the soil.
- Squash vine borer adults emerge the following year.
Identifying Squash Vine Borer
SVB is easier to identify in its adult moth and larva stages:
- Adult Moth: Bright orange abdomen with black dots, wings are greenish-gray, metallic-colored.
- Larva: Creamy-white with a brown head and 1 inch long when fully grown.
Some tell-tale signs of their presence:
- Frass: Sawdust-like material around the stem base.
- Wilting plants: If your squash plants wilt suddenly.
Damage to Squash Plants
SVB causes damage during its larval stage. Due to their feeding habit, they can affect various squash types:
- Most commonly hit: Summer and winter squash, pumpkins
- Less common targets: Cucumbers, gourds, melons
Damage comparison table:
|Plant Type||Damage Level|
|Cucumbers||Moderate to Low|
|Gourds||Moderate to Low|
|Melons||Moderate to Low|
Preventing squash vine borer damage:
- Choose resistant varieties like Butternut and Cushaw squash.
- Use protective barriers, such as aluminum foil collars, around the base of plants.
- Regularly inspect plants for signs of infestation and remove larvae as needed by slicing the stems and covering the wound with soil.
Preventing Squash Vine Borer Infestation
- Crop rotation: Rotate crops yearly to prevent overwintering in the soil.
- Sanitation: Remove and destroy plant debris after harvest to eliminate hiding spots for pests.
- Row covers: Use row covers early in the season to prevent adult moths from laying eggs.
- Foil or plastic cup: Create a protective collar around vines by wrapping them with aluminum foil or using a small plastic cup, ensuring it is at least 2 inches high on the vine and somewhat buried in the soil 1.
- Mint: Plant mint nearby as its strong scent may repel pests.
- Radish: Use radishes as a trap crop to lure pests away from the squash.
- Cucumber: Plant cucumbers, which are less susceptible to squash vine borer attack, near squash plants.
|Crop rotation||Reduces overwintering pests||Requires planning and space|
|Row covers||Protects plants from egg-laying moths||Must be removed for pollination|
|Companion planting||Utilizes natural pest repellents||Not always foolproof|
Controlling Squash Vine Borer
- Regularly inspect plants for signs of infestation
- Look for exit holes and frass near the base of the plant
Detecting squash vine borer infestations early is crucial for controlling the damage to your plants. It’s important to regularly inspect your plants for evidence of the pests, such as exit holes and frass near the base of the plant. This can help you take timely action to protect your garden from these destructive insects1.
- Cut open infected stem lengthwise
- Remove larva and cover stem with soil
One effective method of controlling squash vine borers is by manually removing the larva from the infected plant stem. To do this, carefully cut open the stem lengthwise near the entry hole, and remove the larva inside. Afterward, cover the stem with soil to promote healing and recovery2.
Organic Pest Control
- Neem oil
- Bacillus thuringiensis (B.t.)
- Diatomaceous earth
Organic pest control methods can be an environmentally friendly way to protect plants from squash vine borers. Some popular organic options include neem oil, Bacillus thuringiensis (B.t.), and diatomaceous earth3. Apply these treatments early on to prevent infestations and minimize damage effectively.
Neem Oil Pros and Cons
- Natural and biodegradable
- Safe for beneficial insects
- May need multiple applications
- Can be less effective in high infestations
Chemical Pest Control
- Chemicals specifically designed for squash vine borers
- Use as directed
For severe infestations, chemical pest control might be necessary. Using chemicals specifically designed for squash vine borers can effectively eliminate the pests and reduce damage to your vegetables4. Be sure to follow the label instructions for proper application and safety precautions.
Comparison Table: Organic vs. Chemical Pest Control
|Method||Effectiveness||Environmental Impact||Application Frequency||Safety for Beneficial Insects|
|Chemical||High||Variable||As directed||Depends on the specific chemical|
Other Pests and Diseases Affecting Squash
Squash bugs are a common pest in gardens. They feed on squash plants, causing leaves to wilt and die.
- Adults are flat, dark brown, and about 0.6 inches long.
- Nymphs are smaller, gray to greenish in color.
These insects can be controlled by:
- Inspecting the plants and hand-picking bugs or eggs.
- Using natural predators like wasps.
- Applying organic or chemical pesticides, if necessary.
There are several types of fungal infections that can affect squash plants, causing discolored or diseased leaves.
Examples of common squash fungal infections:
- Powdery mildew: White, powdery spots on leaves.
- Downy mildew: Yellow spots on the upper surface of leaves, grayish-white patches on the lower surface.
To prevent or treat fungal infections:
- Rotate planting locations to avoid spreading diseases.
- Use proper airflow and avoid over-watering.
- Apply fungicides when appropriate.
Squash plants, like all vegetables, require proper nutrients for optimal growth.
Key nutrients for squash plants:
- Nitrogen: Promotes green growth and general plant health.
- Phosphorus: Supports root development and fruit production.
- Potassium: Aids in disease resistance and overall plant strength.
Signs of deficiency:
- Yellowing leaves may indicate nitrogen deficiency.
- Poor root development or stunted growth may be due to phosphorus deficiency.
- Weak stems and vulnerability to diseases can be symptoms of potassium deficiency.
To address nutrient deficiencies, use organic or chemical fertilizers and follow recommended application rates.
Frequently Asked Questions
What Plants Are Affected by Squash Vine Borer?
Squash vine borer mainly affects plants in the cucurbits family, such as:
- Squash: Summer squash, winter squash, zucchini, hubbard squash (including blue hubbard squash), and butternut squash
- Pumpkins and gourds
- Less commonly, cucumbers and melons
Can a Squash Plant Recover from Vine Borer Damage?
Yes, a squash plant can recover from vine borer damage if the infestation is caught early and properly managed. Here are some steps to help your plant recover:
- Scout your plants for the presence of larvae and frass, which is a yellow, sawdust-like material.
- If you notice frass, . cut the vine lengthwise near the entry hole and remove the larva with a small knife.
- Cover the slit stem with soil and keep the plant thoroughly watered to encourage root development.
- Monitor the plant for signs of additional damage or larvae.
How Many Generations of Squash Vine Borer Are There in a Season?
Squash vine borer typically has only one generation per year. Adult moths emerge from cocoons in early summer (mid-June to July), lay eggs on susceptible plants, and then die. After hatching, the larvae feed on the plant throughout the growing season, causing damage to the vines and crowns. Eventually, larvae leave the plant to pupate in the soil, forming cocoons to overwinter and emerge as adult moths the following summer.
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 – Squash Vine Borer
Help ID’ing flying insect
Here’s a couple of photos of a flying insect with hairy orange legs nectaring on common milkweed in MN on 30Jun. Wondering if you could help identify this guy for me? Thanks much.
This is a Clearwing Wasp Mimic Moth in the family Sesiidae. We believe it is a Squash Vine Borer, Melittia cucurbitae. There are many images on BugGuide. The larvae of this moth are a significant pest of squash and other related plants. The colors on your photos do not seem quite a bright, so this may be a related species.
Letter 2 – Squash Vine Borer
Moth or wasp?
Location: southern West Virginia
July 18, 2011 9:38 pm
I found this bug in my bean patch early in the morning and wondered what it was. No internet search could help.
The Squash Vine Borer is a moth that mimics a wasp for protection since wasps sting and moths do not. The larvae bore in the stems of squash plants including zucchini and pumpkin. We are guessing that you have some squash growing near the bean patch.
Letter 3 – Squash Vine Borer
Subject: funky badass looking moth
Location: holmen wi
June 1, 2012 10:56 pm
found this cool looking moth, i thought it was a fly at first but the body is very mothlike. its red and black as you can see, but the wings when looking at them just right are shiny green
Signature: with letters
Dear with letters,
You were very observant to classify this Squash Vine Borer, Melittia cucurbitae, as a moth as it is a very effective wasp mimic. The female Squash Vine Borer lays her eggs on the stems of squash, melon and related plants. The larvae are stem borers and their feeding negatively impacts the health of the plant. You can read more about the Squash Vine Borer on BugGuide.
Letter 4 – Squash Vine Borer
Subject: Colorful bug found in yard
Location: Northern Illinois
June 15, 2013 10:40 am
Found this guy chilling on a tree growing in my backyard before I mowed. Took the picture and then shooed him out of the way so that he wouldn’t become one with the lawnmower.
Do you have a vegetable patch in your backyard and are you growing zucchini or some other plants in the squash family? This is a moth known as a Squash Vine Borer, Melittia cucurbitae. The female lays her eggs on the stems of plants in the squash family and the larva bores into the stems of the plant, often doing killing the plant. See this image from BugGuide of the larvae.
Letter 5 – Squash Vine Borer
Subject: Milkweed visitor
Location: Chicago Area
July 27, 2013 8:35 am
I live just outside of the Chicago area and had this visitor at my milkweed in the beginning of July. This bug was a fast mover and didn’t stick around too long. I have just never seen anything like it. Just curious and would appreciate help! Thanks so much!
Signature: Gina Parks
These are marvelous action photos of a Squash Vine Borer, Melittia cucurbitae, a moth that is a very effective wasp mimic. Normally we get photos of them with squash plants as the female lays eggs on the plants and the larvae bore in the stems of squash and related plants, including cucumbers. You can read more about the Squash Vine Borer on BugGuide.
Letter 6 – Squash Vine Borer
Subject: Friend or Foe?
Location: Southern Plains
August 26, 2013 4:54 pm
I was outside tending to my raised bed vegetable gardens last week when I encountered this fascinating bug. It hovered over my yellow squash and cucumber plants several times so I was able to grab my camera and get at least one good picture of it. I’ve never seen anything like it so I’m curious to know what it is and if it is a beneficial garden predator.
This is a Squash Vine Borer, a moth that mimics a wasp. The larvae bore in the stems of squash and other related plants including cucumbers, so we have to go with foe in the vegetable garden.
Thank you ever so much for your quick reply and help!
I have much to learn yet about the fascinating world of bugs and veggie gardening, as well as how best to navigate your invaluable website!
Hope you have a great day.
Letter 7 – Squash Vine Borer
Subject: Bug on my squash plants
Location: Copperas cove, Texas
May 29, 2014 9:23 pm
Saw this guy on my squash plants, we’re having a hard time keeping bugs from demolishing our garden without resorting to pesticides so we try to remove them individually. This little guy was just relaxing on a leaf and didn’t appear to be doing anything destructive and relocated to our corn to again just hangout it appeared. Any thoughts on what it is? Our google-fu is pretty weak bug wise and we got nothing that way.
Signature: Dave and Kara
Hi Dave and Kara,
If this Squash Vine Borer, a moth that mimics a wasp, lays eggs on your plants, her progeny will bore in the stems, compromising the health of your squash plants. This article from The Urban Garden might provide you with some helpful tips.
Thanks! We’ve got some neem oil and orange oil to try and I got praying mantids today hopefully they’ll take care of them, I’ll definetly give the article a read!
Letter 8 – Squash Vine Borer
Subject: Moth for ID
Location: Ottawa, Ontario, Canada
June 21, 2014 12:17 pm
Well I looked at many websites to identify this orange and metallic blue wasplike moth I’ve recently seen on potato plants, but no luck! The leg uppers are heavily furred while the lower parts are black with white rings. The rear legs are heavily furred the entire length. Wings are slender metallic blue-black. It flies fast but can also hover. This picture was taken in Stittsville, Ontario on June 21, 2014. Thanks in advance for looking!
Do you also have squash or pumpkin plants in your garden? This is a Squash Vine Borer, Melittia cucurbitae, a diurnal species in the Clearwing family Sesiidae, a family that includes many species that mimic wasps very effectively. The larvae are borers that will severely compromise the health of plants in the squash family Cucurbitaceae by boring in the stems.
Thanks so much for the ID! Of course, yes I had squash vine borers last year on my squashes- I completely forgot what they looked like. Thanks again, I’ll keep an eye out for the eggs and damage. Last year I buried the squash leaf nodes which helped root the plant along the ground. Nevertheless, there were a lot of very large grubs in the stems which were needled to kill them.
Letter 9 – Squash Vine Borer
Subject: Found in garden
Location: Central Michigan
June 29, 2014 5:47 am
Hello, I found this in my garden. I’ve never seen anything like it before. Do you have any idea what it is? It is about 3/4 of an inch long.
We just posted another image of a Squash Vine Borer earlier today. Your image is interesting in that it contains the exuvia of the pupa, indicating that your individual just emerged as an adult.
Letter 10 – Squash Vine Borer
Subject: unknown flying insect
Location: central Arkansas NW of Little Rock
May 24, 2015 11:09 am
This insect was in a small group of about 5 or 6 in squash plants. The one I observed was about 15-20mm long and laid one egg on the leaf before moving to another part of the plant. The egg was brown about the size of a small sesame seed. Time frame is Mid-May
Signature: Arkansas Gardener
Dear Arkansas Gardener,
Though it mimics a stinging wasp, this Squash Vine Borer, Melittia cucurbitae, is actually a moth and its larvae are considered pest of squash and other members of the cucurbit family. Additional information is available on BugGuide.
Letter 11 – Squash Vine Borer
Subject: What is this?
Location: New York, ny
June 22, 2015 12:11 pm
I saw this bug sitting in my strawberry patch.
What is it?
Do you have squash or melon plants near the strawberries? This wasp mimic is actually a moth called the Squash Vine Borer. The female lays her eggs on the vines of squash and other members of the family and the larvae bore in the stems, often causing the plants to wither and die. The Squash Vine Borer will not harm your strawberries.
Letter 12 – Squash Vine Borer
Subject: interesting flying red-orange bug with blue/grey vest
Location: Wisconsin, USA
June 26, 2016 9:32 pm
I encountered this guy earlier today buzzing around my milkweed and cucumbers. He was moving pretty quick just like the bees around him.
He/she was approximately 3/4″ long. Red orange in color with bright blue stripes closer the head. I’ve never seen another bug like it.
Asked a few friends and everyone is perplexed and very curious to know.
Thanks for your time. Can’t wait to find out what it might be!
This Squash Vine Borer is a moth from the family Sesiidae, a group that contains moths that benefit from their ability to mimic stinging wasps. Your individual was visiting the milkweed to take nourishment from the nectar, but we believe this is a female due to her interest in the cucumbers. She was probably laying eggs that will hatch into larvae that bore in the stems of squash and other plants in the family Cucurbitaceae, potentially causing the plants to die or at least reduce the yield.
Thank you so much for your quick response! I would have never guessed it was a vine borer! I will have to get out there and inspect my cucumber plant. It was a beautiful bug though. Too bad they are destructive.
Letter 13 – Squash Vine Borer
Location: Suburbs of Indianapolis
June 28, 2016 3:48 pm
I’d love help identifying this insect. It reminds me of a Scarlett Bodied Wasp Moth, but the coloring is a bit off. He lives somewhere in my backyard in Indianapolis, Indiana and frequents my vegetable garden.
Sorry the photos are grainy, he’s very fast.
Signature: Lauren G
You were astute to suspect that though it is an effective wasp mimic, your Squash Vine Borer, Melittia cucurbitae, is actually a moth, however it is from a different family than the Scarlet Bodied Wasp Moth which is a Tiger Moth. Your Squash Vine Borer is a Clearwing Moth in the family Sesiidae. The individual in your image appears to be hovering near some squash leaves, probably to lay eggs. The larva are stem borers and they may seriously compromise the yield of the plants in your garden.