It is disheartening seeing your cucumber plants with spotted or yellow leaves, holes in the leaves, or dead stems. If you look at the leaves, you may see ants. Small, black ants will usually be on the underside of the plant’s leaves. The ants may even cover the entire surface of the leaf. Can ants kill cucumber plants?
Black ants won’t kill cucumber plants, but red or fire ants may. Ants typically do not eat the cucumber vegetable itself, but other objects and insects on the plants including aphids.
Now that you know the ants indicate the presence of aphids, you may have more questions. Let’s dive into what harm the ants and aphids are causing your plants and what to do about both.
Are Ants Harmful to Cucumbers?
Actually, ants do not like the scent of cucumber peel, so they shouldn’t be eating the cucumbers themselves. Some people recommend using cucumber peel as a deterrent to keep ants out of your kitchen. The black ants you see in your garden don’t generally eat vegetables or plants.
However, fire ants (red ants) can damage some vegetable plants, including cucumbers. They may feed on the stems of seedlings and transplants. If they eat enough, the young plant will die.
So, what about the underlying problem when you see black ants on the undersides of your cucumber plants’ leaves?
What insects eat cucumber plants?
When you see holes in your cucumber plants’ leaves, or they’re yellow or have spots, you’ll look for insects. Small, black ants may be on the underside of those leaves. The ants may even cover the entire surface of much of the plant’s foliage.
However, it’s not the ants that are causing the harm. If you look more closely, you will see small bumps that are green, brown, black, or pink. These are aphids. Ants actually “farm” the aphids to get food from them. The aphids produce a sweet, sticky substance called “honeydew.” The ants collect this, filling their stomach, then bringing it back to their nest to feed the other ants in the colony.
Another pest that also produces honeydew is the scale insect. These look like bumps and can appear on both stems and the underside of leaves. But for cucumbers in the garden, the more common insects will be aphids.
How Do Aphids Harm Cucumber Plants?
There are two ways that your plants can be damaged by these insects. In most cases, the plant will survive but can suffer stunted growth and lower vegetable yield.
Attacking the Stems and Leaves
Aphids suck the juices from the stems and leaves of the plant they are attacking. Aphids can reproduce rapidly, making the infestation grow exponentially. This will weaken the stems and can kill new shoots. Seedlings and young plants can die without intervention.
Transmitting a Virus
Aphids can also damage your cucumber plants by transmitting the mosaic virus to them. Signs of this virus are:
- White, light green, or yellow spots on the leaves
- Curled or wrinkled leaves
- Stunted plants
- Misshapen and small cucumbers with warts
There isn’t a cure for the mosaic virus, and infected plants should be pulled and destroyed to prevent it from spreading to other plants. Do not compost them or save their seeds.
Ways to prevent the virus are:
- Keeping aphids out of your garden (see next section for methods).
- Use row covers over seedlings and transplants until the plants start to bloom.
- Disinfect garden tools and wash your hands frequently to prevent the spread of the virus.
- Keep weeds away from the edges of your garden.
- Do not overuse nitrogen fertilizer. This can cause a great deal of new growth, which is what aphids love to eat.
How Do I Get Rid of Ants in My Vegetable Garden?
To eliminate black ants, you must first remove the aphid population. You will need to treat the colony population to get rid of fire ants.
If you spot aphids soon enough, you can control them and prevent further damage to your cucumber plants. It’s advised to pay attention to your plants, especially the underside of the leaves, to look for any aphids.
You will want a solution that isn’t harmful to yourself, your pets, or wildlife. Here are the possibilities:
- Spray the plants with the hose to knock the aphids (and ants) off the plants. However, you’ll have to repeat this and be sure to dislodge all the insects. Use a strong blast, but not so intense that the plant is damaged.
- Apply insecticidal soap or a neem oil spray. You can buy it or make your own. You need the product to reach all of the aphids on the plant to be effective, so you may need to apply it multiple times.
- Introduce ladybugs. Some recommend buying ladybugs to release into the garden. But the ones available this way aren’t native to the US and are aggressive. They can upset the natural ecosystem and carry disease and parasites that could harm native ladybugs. Instead, plant flowers to attract native ones and other beneficial insects. Consider sunflowers, marigolds, cosmos, and the herbs cilantro, dill, and chamomile.
Getting Rid of Black Ants
As you work on eliminating the aphids in your garden, you can use these methods to keep the ants away:
- Spread diatomaceous earth by the mounds and ant trails. This will take time to kill the ants, and you’ll need to reapply after rain once the ground is dry again.
- Use a mixture of borax and sugar or jelly. This is toxic to children, pets, and wildlife, so you must be careful where you place it.
- Cayenne pepper or ground cinnamon can be sprinkled around the plants. This won’t kill ants but is a deterrent.
- Pour boiling water into the anthill. It will take multiple attempts to kill the colony if it is successful.
Eliminating Fire Ants
There will usually be one or more fire ant mounds in the garden or on the lawn next to it. You need to deal with the infestation early on to minimize the damage to your cucumbers and keep the ant population from growing.
You can buy bait specifically for fire ants. It is environmentally safe, inexpensive, and effective. The ants will carry the bait back to the nest, where the other ants will eat it and die.
Growing your own cucumbers can be very gratifying. Cucumbers are a tasty addition to salads and sandwiches and can be used in making infused water and gazpacho.
You’ve learned that the small, black ants you see on your cucumber plants aren’t the cause of any damage you notice. Aphids are most likely the cause of ants appearing on your plants.
You don’t have to let ants and aphids take over your cucumber plants. You may see one of two types of ants, and there are different methods to eliminate each. Multiple options are available for controlling both pests so that you can enjoy your home-grown cukes.
Hi there, my name is Allie and welcome to my blog; GareningWithAllie!
Much of what you see written here is just our personal experiences with gardening. Along with the content I write here, there is also a unique collection of gardening topics covered by some of our close friends. I hope you find everything you read here to be helpful, informative, and something that can make your gardening journey the most lovely experience ever! With that said, Happy Gardening!