How to get rid of black fly on broad beans

Today, we’re continuing our discussion on pest control with another article about blackly on broad beans. Consider how much time you’ve spent in your garden nurturing and watering your broad beans only to discover that they have been infested with blackflies. The following topics will be covered in-depth:

  • Understand what blackflies are.
  • How to spot an infestation.
  • The natural cycle of life.
  • Ways to prevent blackflies.
  • Remove secondary pests.
  • Preventative plants.
  • Use natural predators.
  • Remove the tips of your broad beans.
  • Use Organic and Chemical pesticides.

So we hope you find what you’re looking for here, and that your broad beans are blackfly-free in no time:

black fly on broad beans snippet image

Table of Contents

What Are Blackflies?

Blackfly also referred to as bean aphid, and beet leaf aphid are small, black sap-sucking insects that are often found in gardens. The adults are about 1-2mm in size and have a pointed head and thorax. They also have wings, which they use to fly from plant to plant.

The larvae are small, white and worm-like, with a blackhead. Blackfly feed on the sap of plants, which they extract using their piercing mouthparts.

Aphids secrete honeydew, which can encourage the growth of sooty mould, and they also act as a vector for viruses that cause plant disease.

This feeding damages the plants and can reduce yields. Blackfly are often found on broad beans, but they can also attack other garden plants such as tomatoes, cucumbers and sweet peas.

black bean aphid


So in most cases, when you first spot a blackfly infestation, you’ll notice that they congregate on the top third of the plant. 

This is where they lay their eggs, and it’s also where the new leaves and shoots are. The blackfly will pierce the plant with its needle-like mouthparts to suck out the sap.

Large infestations can weaken broad bean plants and lead to stunted development. If broad beans are badly infested, pod formation may also suffer.

Flower development on ornamental plants like dahlia, nasturtium, and poppies can be disrupted when blackflies feed on the emerging flowers.

In response to aphid feeding, winter-spring host plants such as Philadelphus (Euonymus europaeus), Viburnum (Viburnum tinctorium), and common spindle (Euonymus europaeus) frequently develop curled leaves.

blackfly infestation

The circle of life and Blackfly

We should look at the way nature works to comprehend this more clearly. The weak are sacrificed throughout the natural world in order for the strong to thrive. To put it another way, it’s about who wins in the fight for life.

So plants that are living under stress due to environment, climate, nutrition, or whatever, become sick. 

Then nature sends in the cleanup squad, insects to suck the remaining life from the plants, (in this case blackfly). As the plant dies it falls back into the soil and is eventually recycled into soil again by worms.

So the natural cycle of life removes the weak to make way for the strong. No life is wasted, the nutrients from one plant get transferred to the soil and ultimately into the next plant to take its place.

life recycling

How to prevent blackfly:

Prevention is always better than cure when it comes to blackfly. By taking steps to prevent an infestation in the first place, you will save yourself time, money, and effort in the long run.

There are a number of ways to prevent blackfly, including using organic and chemical pesticides, removing the tips of your broad beans, and using natural predators.

Broad beans require similar soil preparation as other plants, and if you’re growing broad beans, it’s very important to prepare the soil. This should be done at least 12 weeks before your broad beans are expected to bloom.

Apart from that, broad beans don’t require any extra fertilization because of the initial nutrient addition of compost/manure. Too much or too little is just as bad as not enough, and it might harm your plants’ growth.

Broad beans, whether planted in the Autumn or spring, need fertile, free-draining soil with enough direct sunshine or shade. Broad beans require some shelter from the wind and even if you grow dwarf types, they will require support.

healthy plants

Remove secondary Pests – Ants

Many people are familiar with the damage that blackfly can cause to crops and plants. However, what is less well-known is the role that ants play in exacerbating this damage.

Blackfly produce a sugary substance known as honeydew, which is rich in nutrients and sugars. This honeydew is attractive to ants, who will defend the blackfly from predators in exchange for access to this food source.

Unfortunately, this relationship between ants and blackflies can have disastrous consequences for broad bean plants. Ants help spread blackfly from plant to plant, acting as secondary pests. 

In addition, they also help to spread disease, further damaging your broad beans and other plants.

garden pests

Pinch off the tips

Pinching off the tips of broad bean plants before blackflies appear is a gardener’s trick to eliminate a feeding site. 

This not only solves the problem, but it also encourages greater growth and development of robust pods, as well as organic pesticides, the use of natural and chemical pesticides in tandem.

Companion planting

Companion planting is the act of planting different types of plants near each other to improve their growth. This can be done for a variety of reasons, such as to improve soil health, attract beneficial insects, or repel pests.

Some plants are better companions for each other than others. For example, lavender is a good companion for tomatoes because it helps to repel pests such as whiteflies. 

Marigolds are another good companion plant, as they help to improve the health of the soil and also attract beneficial insects.

So let’s look at some of the best companion plants from broad beans:


Alyssum is a beautiful annual flower that can be grown from seeds. It’s a great companion plant for broad beans, as it helps to repel blackflies and other pests.

Alyssum also attracts beneficial insects such as ladybugs, which help to keep the garden healthy. Make sure you don’t plant these too close to your broad beans.


Buckwheat is another great companion plant for broad beans. Not only does it help to attract blackflies and other pests, but it also improves the health of the soil.

Buckwheat is a nitrogen-fixing plant, which means that it helps to add nitrogen to the soil. Make sure to plant away from your broad bean plants.


Cosmos plants (Cosmos bipinnatus) are popular in summer gardens, with a wide range of colors, and frilly texture to the flower bed. Cosmos gardening is straightforward, as well as pleasurable and rewarding when single or double blooms appear on stems that reach 1 to 4 feet (0.5-1 m.) 

They are fantastic at attracting blackfly so make sure you don’t plant them too close.


Dill can be grown in conjunction with broad beans to protect the bean plants from aphid attack; it attracts blackfly larvae. Dill is an annual herb that grows to about 2-3 feet (60-90 cm) tall.

It has thin, divided leaves that are blue-green in colour and have a delicate, sweet odour. The plant produces small, white or yellow flowers that bloom in summer. Dill can be grown from seed, and it self-seeds readily


Allow oregano to blossom in order to keep a constant flow of blackfly feeders coming to your yard. To attract a variety of beneficial insects, we cultivate oregano in large clumps.

Poached Egg Plants

These early-blooming annuals, so named because of their resemblance to a poached or fried egg, are a great addition to our list. Low-growing feathery foliage and lovely blooms produce pollen and nectar to attract beneficial insects in the early spring. These plants are so abundant that one planting is enough; they will self-seed for many years to come, providing new plants for years.


Ladybirds, lacewings, and hoverflies are attracted to tansy, which is used to deter a variety of insect pests. Tansy is an aromatic, perennial herb that can grow to about 3-4 feet (90-120 cm) in height. It has fine, divided leaves that are dark green in colour and have a strong, pungent odour.


Feathery leaves and clusters of white blooms distinguish this hardy herbaceous perennial plant. It may be found in meadows and pastures, and it’s a great way to add height and many beneficial insects to your borders.

cosmos plant good companion for broad bean plant

Introduce natural predators

Ladybirds are a type of beetle that is found in gardens and fields all over the world. They are well-known for their bright red wings and round, black spots.

ladybirds are one of the garden’s best allies, as they are natural predators of blackfly. ladybirds will help to keep blackfly numbers under control, allowing your broad bean plants to remain healthy.

In addition to ladybirds, there are a number of other natural predators that can help to control blackfly populations. These include green lacewings, wasps, and hoverflies.

By introducing these natural predators into your garden, you can help to keep your broad bean plants healthy and free from damage.

introduce natural predators ladybird


Natural Pesticides

There are a number of natural pesticides that can be used to control blackfly. These include neem oil, pyrethrum, and rotenone.

Neem oil is derived from the neem tree and has been used for centuries to control a wide range of pests. It works by interfering with the blackfly’s ability to feed and reproduce.

Pyrethrum is another effective natural pesticide. It is derived from chrysanthemum flowers and works by causing paralysis in the blackfly.

Rotenone is a naturally occurring substance that is derived from the roots of tropical plants. It works by preventing the blackfly from breathing and ultimately leads to death.

Soapy water is also an effective natural pesticide. Simply mix a few drops of dish soap with water and spray it onto the affected plants. The soap will kill the blackfly by suffocating them.

You can create an aphid vinegar spray that is a quick way to kill aphids and blackfly

Chemical Pesticides

There are a number of chemical pesticides that can be used to control blackflies. These include insecticides such as Imidacloprid and Pyrethroids.

Imidacloprid is a relatively new insecticide that works by interfering with the blackfly’s nervous system. It is considered to be very effective against blackfly and other pests.

Pyrethroids are a group of synthetic chemicals that are similar in structure to pyrethrum. They work by causing paralysis in the blackfly and other insects.

neem oil for broad bean killing blackfly


While blackflies can be a nuisance, there are a number of steps that you can take to prevent them from damaging your plants. 

By taking preventive measures, such as companion planting and introducing natural predators, you can help to keep blackfly populations under control. 

If necessary, you can also use chemical pesticides to get rid of blackflies. However, it is always best to use natural methods whenever possible.

broad bean care and health

People Also Ask

How do you get rid of blackfly on broad beans?

Prevention is always better than cure when it comes to blackfly. By taking preventative measures early on, you’ll save time, money, and effort in the long run. Have a look at the points below:

  • Remove secondary pests.
  • Preventative plants.
  • Use natural predators.
  • Remove the tips of your broad beans.
  • Use Organic and Chemical pesticides.

How do you get rid of blackfly naturally?

There are a number of steps that you can take to get rid of blackfly naturally. These include:

  • Introduce natural predators
  • Use soapy water
  • Use neem oil
  • Use pyrethrum
  • Use rotenone

Does soapy water get rid of blackfly?

Yes, soapy water is an effective natural pesticide that can be used to control blackfly. Simply mix a few drops of dish soap with water and spray it onto the affected plants. The soap will kill the blackfly by suffocating them.

soapy water to kill blackfly and aphids

What causes black fly on broad beans?

Blackfly usually attack broad beans because love to feed on the sap from your broad beans and other garden plants. While they are a component of the UK’s wildlife, and will never be completely eliminated, there are methods to manage them and prevent them from destroying your plants that you can do yourself.

Why are my broad bean pods going black?

Incomplete pollination is the most common reason. Broad beans self-pollinate, and they are cross-pollinated by insects, bees, and bumblebees. Pollination of flowers will be incomplete if the bees are not working owing to wet or windy conditions.

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Oliver Wright
Oliver Wright

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