Why Are There Ants on My Zucchini Plants?

If you've suddenly encountered ants on your Zucchini plants, you may be concerned that they will ruin your crop. Ants typically show up on zucchini due to aphids, and few other reasons. In this article, gardening expert Sarah Hyde examines why ants may show up on your Zucchini, and what to do about it when they do!

ants on zucchini

Your zucchini has been growing leaps and bounds, but when you look closer, there is an army of ants on the zucchini plants. Why does this happen and how can you prevent it?

Usually when you see ants, it means you have Aphids on your plants. It’s a common problem with zucchini but many other plants.

Read on to find out more about this common issue, and if it’s something that needs to be corrected, or if it will resolve on its own.

Contents

The Short Answer

There are many reasons for ants on zucchini plants, but no need to panic. The ants are most likely not harming the plants, but instead are busy enjoying the “honeydew” produced by aphids. Honeydew is a sweet, sticky sap secreted by these pests, which ants love to eat. Ants are known to “farm” aphids, which means ants protect the pests and the honeydew from other predators.

Take a moment to observe the ants to see what they are busy doing. They may lead you right to an aphid hot spot! They tend to congregate together, and may look like a mass of tiny, gray, white, or green insects that are each about the size of a ballpoint pen tip. Aphid colonies tend to hide in the nooks and crannies on the undersides of leaves.

Aphids are tiny, soft bodied insects that can look green, white, gray, yellow, or even red or brown. They are pear-shaped and have nearly-invisible legs. Adults and nymphs (immature bugs) look almost identical except for difference in size. Any kind of aphid can make their home on zucchini plants, however you are likely to see melon aphids, which can vary in color from dark brownish-red to yellow or white and are commonly found on cucurbits.

Aphids and Zucchini

This close-up shows a green leaf infested with aphids. The leaf has two large holes and appears to be damaged from the infestation. The aphids can be seen crawling on the leaf's surface, with their small size and bright green color.
Aphids are a common problem for gardeners and can be found in both natural environments and gardens.

Aphids are the bane of gardeners around the world. They occur in the natural environment as well as gardens. The surrounding weeds, native plants, and landscape plants can be host plants for aphids. Though they are common and omnipresent, their honeydew can cause a sticky, yucky film on zucchini fruits that can make harvesting unpleasant and can cause cosmetic damage. 

Aphids enjoy warm temperatures, so gardeners in more temperate parts of the world may see them for a long time throughout the year. If you use row covers or another season extension tool in your garden, they will be present in these warmer microclimates as long as the temperatures are not deeply below freezing. 

Aphids can also be an indicator of poor plant health since they tend to colonize the weakest individual plants. Weak plants have fewer defense mechanisms, just like sickly humans, and animals can be more prone to other illnesses and problems. 

What Damage Do Aphids Cause?

A close-up of zucchini plants thriving in the brown soil. The plants appear to have suffered damage from aphids, as evidenced by the small holes and discoloration on the large, deeply lobed, green leaves. Their branches are thick, sturdy, and green in color.
Aphids cause damage by piercing plant tissue and sucking out water.

Large, healthy zucchini plants may tolerate a light amount of aphids without sustaining signs of damage. When aphid populations increase, you may see more symptoms.  Ants are a great indicator of aphid presence; there are many other signs you can look out for. 

Signs of Aphids

Signs of aphids include honeydew, which may appear white or gray if fresh or black if it is older and has fed the growth of a sooty mold. Curled, stunted leaves are also a sign. They may be hanging out inside the leaf curl. 

These pests damage plant tissues by sucking mouthparts that pierce the leaf wall and suck out water from the plant tissue. This unsightly damage can range from mild speckling, which causes few issues, to severe stunting, yellowing, and curling of leaves.  

Virus Spread

The biggest problem with aphids’ piercing-sucking feeding is that they can transmit the Cucumber Mosaic Virus (CMV). Unfortunately, CMV can also be spread through contact with a gardener’s hands or pruning tools. So once the disease is introduced, you must be careful not to transmit the disease to other crops in your garden.

While cucurbits are especially susceptible, many other plants can get CMV, including nightshades, legumes, and some woody plants. The virus will show up as:

  • Yellow-green mottled foliage
  • Mosaic leaves and fruits
  • Stunted, yellow plants

Preventing pests will help lessen the chances of CMV affecting your garden.

The Good News

Aphids’ mold-like appearance and honeydew-covered leaves can be unappetizing, especially on leafy green crops where the edible portion has aphids on it. Fortunately, mild aphid damage does not hugely affect the eating quality of most crops.

Still, it can be a mess to clean post-harvest. Wash aphids from harvested crops using clean water, and spray with a strong blast of water or rub and rinse vigorously to dislodge the aphids.  

How Do I Prevent and Get Rid of Aphids?

A gardener wearing yellow gloves uses a water hose with a spray nozzle. The gardener is standing in front of several plants and appears to be spraying them with water. The water droplets can be seen in the air.
Using a strong stream of water from a garden hose is an effective physical method to control aphids.

Aphids can be difficult to get rid of in any garden situation. Looking at the garden with an Integrated Pest Management (IPM) lens, totally eradicating aphids is difficult, if not impossible. It is not a realistic goal. Rather, IPM suggests implementing cultural and physical controls first, which aim to be preventative, then using chemical control as a last resort. 

Choose Resistant Varieties

Always check transplants for aphids before planting to avoid introducing them into the garden. Scout wild plants adjacent to the garden to ensure they aren’t acting as a safe haven. Choose CMV-resistant seed varieties and buy only disease-free transplants. 

Ensure Airflow

Another cultural control for aphids is to prune or space plants properly so there is adequate airflow between leaves since aphids prefer tight, protected spaces. Zucchini plants can be moderately leaf-thinned to increase airflow with little reduction in production as long as the wounds are allowed to heal in warm, dry weather. 

Don’t Over-Fertilize

Aphids also thrive on plants that have access to too much nitrogen, so apply no more fertilizer or manure than necessary, and always follow the fertilizer application directions from the manufacturer. The best fertilizer for zucchini is slow-release.

Spray Them Off

Physical controls for aphids include spraying them off the plants with strong jets of water from a garden hose. Scouting and spraying aphids off with water is an ongoing garden chore as long as temperatures are warm. 

Improve Soil Health

Work to improve soil health in the long term. Pests tend to colonize sick or weak plants before choosing healthy plants. Improve the soil health by minimizing disturbance during garden prep, adding compost, and using organic (not plastic or synthetic) mulches when possible, which eventually help build soil organic matter. 

But I Still Have Aphids and Ants On My Zucchini!

A close-up of a ladybug can be seen on top of a surface. The ladybug has bright red and black markings, with its wings visible on its back. The surface appears to be a plant or leaf, with small, hair-like structures covering it.
Keep spraying water on aphids and search for their sources in wild plants around your garden.

If you are still having aphids and ant problems on your zucchini, be persistent in spraying aphids off with water. Continue to scout wild plants around your garden for aphid sources. You can also employ biological control, which uses beneficial insects to feed on aphids.

Biological Control

Release ladybugs into your garden as beneficial insects. Ladybug larvae are voracious consumers of aphids. Lady beetles, aka ladybugs, are well-known predators of aphids. The larvae are the major aphid-eater, and they resemble a mini-caterpillar with purple, orange, gray, and black markings. Ladybugs can be purchased online for delivery through the mail and released in your garden. 

Note that the lady beetles sold are mature adults and do not consume as many aphids as the larvae. This means there is some time between when you release adults to when they lay eggs and hatch out a new generation of larvae, the best aphid-eaters. Be patient!

Chemical Control

The last resort of pest control is chemical application. Be aware any chemical used for pests may negatively impact any beneficial insects in your garden, either natural or introduced. Before choosing chemical options, decide how many aphids or ants you can live with, and consider changing your perspective. Most plants can tolerate mild aphid damage.  

If all of the above have not helped, choose the ecologically least-harmful chemicals possible. A mild soap and water spray can do the trick. Horticultural oils and insecticidal soaps can also be used. However, be sure to read the application directions and follow them exactly. 

How Do I Get Rid of Ants on Zucchini?

Eliminating ants from a garden is challenging due to large underground colonies.

Ants congregate where aphids are, but ants rarely cause damage themselves since they are interested in the honeydew. Ants may be undesirable if you are at work among the plants and they crawl on you or bite.

Otherwise, ants are not usually eating or damaging the zucchini plants. Ants are – for the most part – beneficial to humans and the ecological world. Ants clean up messes, from animal and insect carcasses to decaying plant matter. 

Ants are also difficult (if not impossible) to eliminate in any garden situation. Waging a battle against ants is akin to emptying the ocean with a bucket. There are too many ants in well-established colonies deep underground to eradicate them from the garden completely.

From an IPM perspective, eliminating ants is not realistic, but there are cultural and physical controls to discourage ants.

Physical Control

How much benefit or nuisance ants are, it is wise to discourage ants from further farming aphids on your garden plants. A physical control for ants is to discourage them from climbing zucchini plants by using a wide band of diatomaceous earth at the base of the plants. Diatomaceous earth must be reapplied after rain or when it gets too wet, as it loses its utility when it gets overly damp.

Unfortunately, ant baits or poisons do not reliably work for long-term ant control outdoors since there is a continual source of new ants to move in, plus baits can be a risk to children or pets.

Having said that, you can reduce the number of ants by making a DIY ant bait. Mix equal parts of peanut butter, honey, and Borax (a naturally-occurring mineral mined from the earth) together to create a paste, then place dollops of this on slips of paper and place the bait blobs in ant trails.

The peanut butter attracts the protein or fat-loving ants, the honey attracts those that often farm aphids for honeydew, and after they tote the bait back to the ant colony, many of them will die off. Keep this ant bait away from children or pets who might be enticed to eat it; it’s not good for them, either!

How to Optimize Zucchini Plant Health

A close-up of a zucchini plant with multiple fruits, positioned on a bed of brown soil. The fruits are elongated, shiny, and green, while the plant's leaves are large, deeply lobed, and green with white markings. Its green branches are thick and slightly ribbed.
Zucchini prefers hot, humid weather and fertile soil with ample water.

Ants on your zucchini may signal you need to return to the source and optimize plant health.

Most all summer squash plants require the same care. The term “zucchini” usually refers to the green-skinned summer squash, though the term can be used for yellow summer squash or yellow-skinned zucchini (like the variety “Gold Rush”).

If that’s not confusing enough, the term summer squash is generally reserved for yellow-skinned crookneck-type squash but can be used interchangeably for green zucchini. 

Weather

All zucchini thrives in hot, humid weather in fertile soil with lots of water. Zucchini are not frost tolerant at all and will die with freezing temperatures.

Wait until the threat of frost has passed to set out transplants or seed zucchini in the garden. Occasionally, a mature plant can be slightly frosted early in fall and continue to produce, though production will slow down. 

Mulch

Mulching your zucchini plants will help keep down weeds and their associated pests. This also reduces soil splatter on the fruit to help curb disease problems. If you choose not to mulch, keep the plants weed-free while they are young. The large leaves will shade out most weeds as the plants grow. 

Proper Spacing

Plan for zucchini plants to take up a lot of space in your garden, at least 4 feet across for mature plants. Some zucchini varieties are very compact, while others vine continuously and can grow up to 8 feet long.

If space is of concern in your garden, choose a compact variety. If you grow in raised beds or garden boxes, help direct the zucchini plant to grow over the edge rather than taking over the entire bed to maximize space.  

Varietal Selection

Zucchini varieties come in a spectrum of flavors, colors, and shapes, from round “eight-ball” zucchini to green and yellow hybrid crook necks. One particularly stand-out variety is ‘Costata Romanesco,’ an Italian heirloom variety with an exceptionally nutty flavor and firm texture. ‘Costata Romanesco’ is an enormous plant with a spreading habit.

Yellow crookneck summer squashes tend to have a tender texture and sweeter flavor than the firm dark green zucchini and should be picked when the skin is bright yellow and shiny for best flavor.

Harvest Regularly

Zucchini is at its prime flavor and texture when the fruits are small (under 12” in length), and the skin is bright and shiny.  If you want small fruits, be prepared to harvest zucchini every day during the hot, long days of summer to keep up with the fast-growing fruits. Harvesting the fruit regularly also helps keep the plant producing new fruit

Zucchini grows so quickly that it is easy to have baseball-size fruits if you neglect to harvest for a few days. When the zucchini skin becomes dull and dark green, the flavor is less, and the texture can turn spongy. Overgrown fruits are still edible and can be useful for shredding to make zucchini bread, muffins, and cookies.

Final Thoughts

Finding ants on your zucchini may cause alarm, but the ants are generally not causing damage. Rather, they may be signaling you to a possible aphid infestation. Aphids and ants can be a frustrating problem for gardeners who grow zucchini and almost any other crop, but persistence pays off in prevention and control efforts.

Minor aphid populations should not cause panic, and most plants can still provide a reliable harvest with light aphid damage.

Work to continually improve soil health through increasing organic matter and plant flowers to encourage beneficial insect predators in your garden. A combination of physical, cultural, and biological controls and prevention can greatly reduce aphid and ant problems.

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A ladybug rests on a yellow umbel flower. ready to prey on pests like aphids.

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