Ants on Cucumbers: Why it Happens & Prevention

You are out in your garden, enjoying a beautiful day when you see an unusual amount of ants on your cucumber plants. What are they doing there? Why are they only on your cucumbers? Is there something especially attractive about this popular garden grown vegetable that makes them so attractive to ants?

There’s a short answer and a longer answer to this question. In this article, you’ll learn all the details of both the long and short versions! But it all comes down to what attracts ants to your cucumbers, and how you can prevent it from happening in the first place.

Curious to learn more? Let’s continue diving into why ants may love the cucumbers in your garden, and how to treat it. We’ll at the most important aspect, which is how you can prevent them from getting there in the first place.

The Long Answer

There are many reasons ants may be on your cucumber plants. The most likely reason is they are busy enjoying the “honeydew” produced by aphids. Honeydew is a sweet, sticky sap secreted by aphids, which ants feed on. Ants are known to “farm” aphids, which means ants protect the aphids 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! You may see a mass of tiny, gray, white, or green insects that are about the size of a ballpoint pen tip. Aphids tend to congregate in the safety of 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. Adult and nymph (immature) aphids look almost identical except for differences in size.

Any kind of aphid can make their home on cucumbers. However, you are most likely to see melon aphids, which can vary in color from dark brownish-red to yellow or white. They are commonly found on cucurbits.

About Cucumbers

Cucumbers thrive in hot, humid weather in fertile soil with lots of water. They are not frost tolerant at all, and will die with a light touch of frost. Most cucumbers mature in Mulching can help keep down weeds and their associated pests. They can also help reduce soil-splatter on the fruit – both of which help curb disease problems.

Cucumbers can be grown either sprawling on the ground or trellised. Trellising can help keep the fruit clean and reduce disease and insect problems. Trellised fruit tends to be more susceptible to sun scald than non-trellised, and trellising is an extra expense and labor.

Cucumber varieties come in a wide spectrum of flavors and uses. Growing different varieties helps add interest to the garden and salad plate. Certain varieties are also more pest resistant, which is something to consider when picking a particular cucumber type to grow.

Unique cucumber varieties include lemon, which are yellow and round, with a faint citrus taste, and gherkins, whose  tiny, spike-covered fruit is excellent for pickles.

What Causes Aphids?

Aphids are a frustration of gardeners around the world. They occur in the natural environment as well as gardens. Often the surrounding weeds, native plants, and landscape plants are host plants for aphids.

Aphids enjoy warm temperatures. Gardeners in more temperate parts of the world may see aphids for a long time throughout the year.

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

What Damage Do Aphids Cause?

Large, healthy cucumber plants may tolerate a light amount of aphids without sustaining signs of damage. When aphid populations increase, you may see signs of aphids and symptoms from diseases they carry.  Aside from ants indicating presence of aphids, there are many other signs and symptoms a gardener can look out for.

Signs of aphids include the 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 of aphids, and they may be colonized safely inside the leaf curl.

Aphids damage plant tissues with their sucking mouthparts. Thier mouth will pierce the leaf wall and suck out water from the plant tissue. This damage is unsightly. It can range from mild speckling which causes few issues, to severe stunting, yellowing, and curling of leaves. 

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

While cucurbits are especially susceptible, many other plants including nightshades, legumes, and some woody plants can get CMV. CMV will show up as yellow-green mottled or mosaiced leaves and fruits, and stunted, yellow plants, along with other symptoms. Preventing aphids will help lessen the chances of CMV affecting your garden.

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.

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

Aphid Prevention & Treatment

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 to do, and is not a realistic goal.

Rather, IPM suggests implementing cultural and physical controls first. These aim to be preventative, then using chemical control as an absolute last resort.

Cultural controls for aphids include checking transplants for aphids before planting to not introduce them into the garden, and scouting for wild plants adjacent to the garden that may be natural habitats for aphids. Choose to plant CMV resistant varieties in the seeds you plant, and buy only disease-free transplants.

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.

Aphids also thrive on plants that are given too much nitrogen, so apply no more fertilizer to your cucumbers than necessary, and always follow the application directions from the manufacturer.

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.

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, add compost, and use organic (not plastic or synthetic) mulches.

I Did All That – But Still Have Aphids

Be persistent in spraying off the aphids with water. Continue to scout wild plants around your garden for aphid sources. Use biological control: employ beneficial insects that feed on aphids to do some work.

Lady beetles, aka ladybugs, are well-known predators for aphids. Lady beetle larvae are the major aphid-eater, and they resemble a mini-caterpillar with purple, orange, gray, and black markings. They 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 that there is time between when you release adults, to when they lay eggs and hatch out a new generation of larvae, who are the best aphid-eaters.

You can also use a popular method of pest prevention called companion planting. This method requires planting plants that won’t compete for nutrients along with you cucumbers. These cucumber companion plants will help ward off pests, and can actually provide beneficial nutrients to the cucumbers in your garden.

Pesticides can cause harm to beneficial insects and pollinators in your garden, so we don’t recommend using pesticides unless you have no other option. If you decide to use pesticides, stick to an organic formula, that only uses natural ingredients.

Getting Rid of Ants on Cucumbers

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 working in the plants and they crawl on you or bite.

Otherwise, ants are not usually eating or damaging the cucumber 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.

They are also difficult if not impossible to get rid of in any garden situation. There are simply too many of them in well-established colonies deep underground to eradicate them. From an IPM perspective, totally eliminating ants is not realistic, but there are cultural and physical controls to discourage ants.

How much benefit or nuisance ants are, it is wise to discourage ants from further protecting the aphids. A physical control for ants is to discourage them from climbing cucumber plants by using a wide band of Diatomaceous Earth at the base of your garden beds. Unfortunately, ant baits or poisons do not reliably work for long-term ant control outdoors, since there is a continuous source of new ants to move in.