Have you noticed the fresh spring growth not being able to grow as vigorously as usual on one of your plants? Do you notice mottled, yellow, or curled new leaves? Are your Roses mysteriously not blooming?
Chances are, your plants are under attack. A Black Aphid attack!
Black Aphids are a commonplace plant pest, and gardeners and houseplant parents all around the world have had at least a few happenstances of dealing with them.
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How to Get Rid of Black Aphids
Close monitoring of plants comes first in getting rid of Black Aphids. Remove the Aphids by tugging them off with your hands or a strong water spray. Use organic remedies such as dish soap solution or Neem oil to kill Aphids. Beneficial bugs and Aphid-repellant plants will help in the long term.
Identification of Black Aphids
Black Aphids are tiny, gray-black colored, soft-bodied insects. Young Aphids have broad bodies with no wings, while mature Aphids may grow wings at the end of the season and grow more elongated. They are usually found on the underside of leaves and on new, soft growth. The size is no more than 2mm.
The Black Bean Aphids, scientifically known as Aphid fabae, are tiny, gray-black colored, soft-bodied insects. The broad-bodied insects are also known as Blackfly, Bean aphids, or simply Black Aphids.
They can reproduce asexually, producing generations upon generations of Black Aphids feeding on your plants.
Unfertilized adult female Aphids will give birth to more female aphids, increasing the intensity of Black Aphid infestation if there’s no intervention.
Throughout a Black Aphid’s lifespan, one insect will shed 4 times, leaving tiny white flakes on the underside of the foliage. Recognition of these flakes is a surefire way of confirming an Aphid infestation.
The insects have dark green to black bodies with light-colored, yellow legs. The average length of a Black Aphid is 2mm.
The highly developed mouthparts of Aphids allow them to feed on plant nutrients flowing in the outer nutrient uptake channel, the phloem.
The micro-sized stylets, or mouthparts, are able to perforate individual cells rather than inflict a wound upon the plant’s body. This also makes Aphids the perfect transmitters of viruses to the host plant.
Black Bean Aphids are much easier to identify than Aphids of other colors. They are usually found in clusters, sucking sap on the underside of leaves, on sprouting buds and blooms, and on soft, herbaceous stems.
Black Aphid presence can be confirmed by spotting the insects themselves, finding the sticky substance, honeydew under the leaves, or spotting the tiny white flakes they leave behind when they molt.
Direct Effects of Black Aphid Infestation
The primary outcome of a Black Aphid infestation is the precious plant sap being sucked out of the plants. The specialized mouthparts can pierce through the cell walls to access the essential nutrients present in the phloem.
As the young and adult Aphids feed on the plant sap, it drastically reduces the nutrients essential for growth, which in turn alters the growth hormone balance within the plant.
The direct result of plant sugars and other components of the sap being sucked out of a plant is retarded growth and distorted foliage growth.
Black Aphids concentrate on the newly growing leaf and flower buds for their soft tissue and high concentration of sugars.
If the infestation occurs really early on in a plant’s life, Blackfly invasion can lead to the young plant dying because it cannot produce enough foliage and keep up with the constant nutrients being sucked out of it.
All in all, a Black Aphid infestation leads to reduced growth and drastically reduced yield in crops.
You may wonder how can such tiny insects possibly do so much damage to a big and healthy plant?
Well, there’s a lot more to it than just Aphids slurping sap from your plants. It’s a lot of Black Aphids slurping up a lot of sap from your plants!
Black Aphids will reproduce like crazy and will increase from a few dozen to a few thousand in a matter of days. Moreover, each Aphid will suck a tremendous amount of plant sap from the new growth.
The sap is rich in sugars, but the protein content is very low. To fulfill their protein requirements, Black Aphids will suck up a lot more sap than they need.
They secrete a full-of-sugar, sticky substance called honeydew on the leaves while they continue to suck more sap. And thousands of Aphids doing this in amalgamation results in a disaster for the plant, and you, the plant parent.
Indirect Effects of Black Aphid Infestation
Apart from plants losing a lot of precious sugars and their growth getting stunted, there are also other, more severe implications of a Black Aphid infestation.
As the tiny insects feed, they excrete a clear, sticky substance called honeydew on the foliage. Due to its sticky properties, honeydew remains on the leaves and is hard to remove.
Honeydew itself is not harmful to the plants, although drops of this substance hanging about your plant are an unwelcome sight.
Honeydew, however, attracts the growth of Sooty Mold and a lot of other harmful insects to your plant. Sooty Mold is dark, gray, or black colored fungal growth wherever honeydew is present on the foliage.
This black fungal growth isn’t technically a disease but more of a hindrance in the way of your plants and good health.
The black Mold covers the leaves and can completely engulf them. Depriving the foliage of light, and hence, slowing down photosynthesis and food production.
Sooty Mold infected leaves will turn yellow, die, and drop. Causing premature leaf drop, and in worst cases, plant fatality.
That’s not all. While the stunted plant growth due to Aphid infestation and the resultant Sooty Mold are resolvable issues, Black Aphids may infect your plants with permanent, physiological diseases.
Aphids, more particularly Black Aphids, are one of the most common virus vector insects that can infect plants with more than 30 fatal viral infections.
As mentioned above, Black Aphids have specifically designed stylets that puncture the plant’s outer cell without wounding and are perfect for the transmission of viruses.
Although Aphids themselves are not the source of the virus, they are famous for transmitting viruses from one plant to the other.
Plants’ Natural Reaction to Black Aphid Infestation
Nature has its own way of dealing with problems. Plants are much smarter than we think they are, and they can defend themselves pretty well in natural conditions.
In response to a severe Black Aphid attack, stressed plants respond in an ‘indirect defense’ by calling out for help. Yes, you read that right.
Plants release volatile compounds around them, which are recognized by beneficial bugs as a call. These compounds attract natural Aphid-predators towards the plant.
This is known as “cry or call for help” from a plant, and this is really the plant calling its friends to take care of the Aphid problem it’s facing.
Plants attract a range of Black Aphid-eating insects, and as the friendly bugs hunt down the Aphid population, the plant is relieved of the stress it is under.
However, you cannot rely on this natural Black Aphid control mechanism for plants growing in your home or garden.
Your plants, apparently, are not growing in the wild and will not be able to attract as many Aphid-predators as they need to deal with an Aphid problem.
Taking action is up to you!
Control of Black Aphids
Upon identification, Black Aphids can be manually removed from the plants by hand or by spraying a strong stream of water on them. As you remove them, make sure they fall into a bucket of soap water. You can also use dish soap solution or Neem oil mixed in water and detergent to kill Black Aphids.
Closely Monitor Your Plants for Black Aphids
Keep a vigilant eye on your plants. Observer the foliage, the undersides of leaves, and new growth when you are watering or fertilizing your plants.
A Blackfly infestation is most likely during the growth period when there are a lot of buds and blooms growing. So be extra watchful in spring and early summer.
Being able to catch a Black Aphid infestation when it’s developing is the most important aspect of Aphid control.
If you nip the problem in the bud, you won’t have to deal with Sooty Mold, viral plant diseases, and reduced growth and yield.
Observation at least twice a week is needed. If the problem goes unnoticed only for a week or two, Black Aphid control may become quite unmanageable.
This is especially true for early summer when the temperatures are mildly warm but not hot. This is when Black Aphids can deal the most damage to your plants.
A Black Aphid infestation is most likely to be found at the upwind end of your garden or in the vicinity of other infested plants. If you discover an Aphid infestation, be sure to check nearby plants too.
A high concentration of Black Bean Aphids’ natural enemies such as ladybugs, lacewings, and others might indicate a high concentration of the pests in that area.
If you spot a lot of disease-killed or mummified Aphid bodies, it is a sign that the natural elements are working well to fight the Blackfly invasion.
Ants tend to Aphids and form a symbiotic relationship with them. If you find unusual ant activity on or near a specific plant or ants in the soil, chances are they are there for the Aphids!
Aphids are an excellent food source for ants, and ants will protect Aphid populations from other natural Aphid predators. Hence, an essential part of getting rid of Aphids is dealing with their protectors first, ants!
Removing Black Aphids Manually
When you spot a colony of Black Aphids feeding on the undersides of one of your plants, don’t wait. Act immediately.
Get your gloves on and start knocking the Aphids off of your plants. Although they will not be able to recover if they fall to the ground, you should use a basket of soap water to drop them into.
Take care not to knock Black Bean Aphids only to have them falling over another plant. You’re only going to spread the infestation further this way.
Bend the stem down to where it’s safe to remove the pests and shake them off or gently nudge them off of the foliage.
If the infestation is severe and spread over the whole stem, you can prune it all and immerse it in soap water to kill the Aphids.
Another method to remove Black Aphids by hand is to use a strong stream of water to wash them off. Using a water stream is much more effortless than removing tiny insects by hand.
Set your garden hose to high pressure and set the level to a fine but strong spray. This method is not very practical for young and delicate plants.
Here too, you must ensure that the water washes the Aphids away on the ground or in a bucket so they do not get on any other plants.
These methods are the emergency treatment you should give Black Aphid-infested plants as soon as you identify an infestation.
By removing the majority of Bean Aphids, you will stop the continuous loss of plant sap from your plant and help it revive itself.
Homemade Black Aphid Remedies
Dish Soap Solution – Use a pure liquid soap such as Castile to prepare soap water to ward off Black Aphids. Take care not to use standard commercial dish soaps as they contain harmful ingredients.
The soap you use should no contain fragrant elements, moisturizers, degreasers, or have any anti-bacterial properties. Also, ensure you are using pure Castile soap and not a detergent.
Detergents are chemically prepared and will have harmful effects on plants.
On the other hand, pure soaps are prepared from natural vegetable oils and will not harm plants if used in moderation.
Prepare the solution by mixing one tbsp. liquid Castile soap into a quart of water. If you need to treat a large amount of foliage across many plants, add 5 tbsps. to every gallon.
Mix the soap and water thoroughly until the soap is fully dissolved. Add to a spray bottle or spray can and head towards the plants.
Always conduct a test spray before the actual spray treatment for your plants when using soap or other chemical pesticides. Spray a part of the foliage and wait for a day to make sure no side effects appear.
If you’re sure there are no side effects, treat the whole plant with the spray. Soak the undersides of leaves and the new growth.
The best time to spray is in the early morning or the evening when the temperatures have decreased. This ensures the soap water will not evaporate quickly and gets absorbed into the leaf surface fully.
Spray 3-4 times a week initially and 2 times a week after the Black Aphid population has subsided.
Neem Oil – The organic aromatic compounds found within Neem oil act as natural repellents against Black Aphids. However, Neem oil applications will also ward off other beneficial insects.
To use Neem oil on your houseplants, you will need to create a solution with water and an emulsifying agent.
Being an oil, Neem oil will not mix very well with water, so you need to add a combining agent such as mild dish detergent to help it dissolve well.
Add 2 tbsps. of dish detergent to a gallon of water. This meager amount is recommended as detergents in higher concentrations are harmful to plants.
Add 2 tbsps. of 70% Neem oil to the water and detergent solution and mix them well. Put in a spray can and spray over your plants until they are well soaked in the Neem oil solution.
Reapplication every 2 weeks is recommended for a long-term Black Aphid solution.
Prevention of Black Aphids
Prevent a Black Aphid infestation in the future by spraying mild Neem oil solution over your plants every 2 weeks. Additionally, you could take the assistance of beneficial bugs to keep Aphid populations in check. Strategic positioning of plants is also an excellent way to keep away Black Aphids.
Using Beneficial Bugs to Control Black Aphids
Rather than manually removing Black Bean Aphids off of your plants and using pesticides, you can also use a more interesting, natural method to control the pests.
Attracting or introducing natural Aphid predators in your garden is an excellent way to let nature deal with your problem.
Although you won’t be able to employ this method for indoor plants, it is an excellent and effortless method to rid your garden of all kinds of pests. Just let the food chain take its path, and soon you’ll have pest-free, healthy plants.
Ladybugs, Green Lacewings, and Parasitic Wasps are the most effective Aphid controller insects. They will not harm you or your plants. In fact, they will help with pollination.
Parasitic Wasps lay eggs in the Black Aphids’ bodies. This is how an Aphid becomes parasitized, and as the eggs hatch, the Aphids will die and turn brown, forming a mummy.
If you notice a lot of Black Aphid mummies on or near your plants, it’s an indication that the Wasps are performing well, and the Aphid population will be well under control in a matter of days.
Other bugs such as Ladybugs, Lacewings, and Predatory Beetles feed directly on Aphids.
The best thing about having these bugs is that they’ll crawl around every nook and cranny of your garden and to the most inaccessible parts of plants in search of a tasty Black Bean Aphid meal.
Not only will these insects start feeding on pest insects immediately, but they will also reproduce fast, increasing in population and diminish Aphid populations exponentially.
Green Lacewings are an incredibly effective pest control insect. A female Lacewing lays hundreds of eggs in every clutch. The hatched Lacewing larvae will feed on almost 600 aphids every day.
Lacewings are attracted to sweet-scented flowers. Attract these insects near your Aphid-infested plants by placing fragrant flowers nearby.
If you’re releasing Ladybugs, Lacewings, or any other beneficial bugs bought commercially, do so in the dark. Releasing the insects during daylight will result in most of them flying right away.
You also have to check if any ants are protecting the Aphids and not letting beneficial bugs do their job.
To prevent ants from accessing the Aphid populations on top of plants and trees, mark a boundary with a sticky substance at the base of the plants to prevent ants from traveling up and down the plants.
Cordon off the area by using ant repellents or wrapping duct tape around the base of the plant and putting sticky glue over it so ants cannot pass it without getting trapped.
If you have an excessive ant population in your garden and stopping them is getting difficult, you can also use ant traps to catch and kill them to regulate their population.
Growing Aphid-Repellant Plants
Strategic planting and plant positioning can go a long way in protecting your plants from Black Aphids and other pests.
Herbs with strong scents like Oregano, Sage, Chive, Garlic, Onions, and other herbs can effectively deter Aphids from their vicinity.
Growing these strong-scented plants in areas of your garden that get infested most often will help a lot. In the same way, plants like Mint, Clover, Dill, and Fennel will attract beneficial bugs that feed on Black Aphids.
Sacrificial plant growing is another excellent and innovative method to protect your garden from Aphid attacks.
You can use plants that Aphids are attracted to the most and place them in a far corner of your garden. They will lure the pests away from the plants you want to protect.
Moreover, eliminating Aphids is much easier by treating these sacrificial plants with pesticides where they are concentrated the most.
Plants like Nasturtium, Zinnias, Cosmos, and Mustard are excellent sacrificial plants that Black Aphids love.
Frequently Asked Questions about Getting Rid of Black Aphids
How to dispose of Black Aphid-infested foliage?
If you have pruned off a severely infested part of a plant, carefully place the whole branch in a plastic bag and seal it. Do not shake the removed foliage to prevent the Aphids from falling off and getting onto other plants.
Where do Black Aphids lay eggs?
Black Aphids usually lay their eggs under the protection of dead plant matter. Remove all dead plant matter from the ground before the onset of winter to prevent Aphids from overwintering in your garden.
Do Black Aphids have wings?
Wing mutations are triggered in Black Aphids late in the season when the plant source gets too crowded for the Aphids. The insects grow wings and fly to other plants to feed and also lay eggs for the winter.
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.