Brown aphids on plants are opportunistic invaders that thrive on the tender succulence of your prized plants, transforming the once-peaceful scene into a battleground where leaves curl, flowers wilt, and the very essence of your garden is under siege. Their ravening appetites and ability to reproduce rapidly present a challenge that even seasoned gardeners must courageously face.Brown Aphids Damaging Plants

Now, as you go ahead and read this article, you will have a deeper comprehension of the causes that attract brown aphids to our plants, as well as a handful of ways to reclaim your garden.

What Are the Causes of Having Brown Aphids Target Your Plants?

The causes of brown aphids targeting your plants are environmental factors, previously infested plants, and weakened plants. In addition, it could also be due to the physiology of the plant, having tender growth, and it can also be because of having a host preference.

Brown aphids target your plants because environmental conditions favor their growth and reproduction. The physiology of the plant, or if it is weakened, or has tender growth, can also attract them.

However, if your plants have been infested previously or are one of the preferences of brown aphids, it can cause brown aphid infestations. From the brown citrus aphid to the corn leaf aphid or spotted alder aphid, as a plant enthusiast or green thumb, you might find yourself in a constant battle to protect your beloved plants from these tiny yet relentless pests.Causes of Having Brown Aphids on Plants

– Environmental Factors

Environmental factors can create conditions that favor aphid reproduction, growth, and survival, leading to an increased likelihood of infestation. Temperature, for example, can influence the presence of brown aphids, as warm temperatures from 70 to 80 degrees Fahrenheit promote aphid activity and reproduction.

High humidity can also create an ideal environment for aphids, allowing them to absorb moisture and preventing dehydration. Moist foliage provides a suitable habitat, encouraging them to reproduce and build colonies. Areas with poor air circulation, such as dense plantings or crowded conditions, can boost humidity levels, increasing the attractiveness of plants to brown aphids.

– Previous Infestations

Previous infestations can catalyze brown aphids to invade your plants, as they can leave behind traces that attract subsequent generations and make your plants more susceptible to future attacks.

As you have this in mind, it would be triggered when aphids feed on plants, because they leave behind secretions and other chemical compounds that act as attractants for other aphids, signaling the presence of a suitable food source and a conducive environment for reproduction.

Moreover, the honeydew produced by aphids is a sticky, sugary substance excreted by them as they consume plant sap during feeding. The latter can also attract subsequent infestations, as they can sense these cues and recognize them as indicators of suitable feeding sites.

– Weakened Plants

When plants are weakened due to stress, nutrient deficiencies, or other factors, they become more susceptible to aphid infestations as they often exhibit compromised defense mechanisms. The production of their natural repellents may have reduced, or they might need more resources to mount a strong defense against aphids. Hence, their tissues become easier targets for aphids to access and penetrate, providing them with a favorable feeding site.

Stressed or nutrient-deficient plants may produce chemical compounds that act as a beacon for aphids, signaling the presence of a vulnerable host plant. Brown aphids can easily detect these chemical signals, honing in on weakened plants as a source of sustenance.

– Plant Physiology

The physiological characteristics of your plants can influence their susceptibility to aphid infestations, as plants that naturally produce sap with higher nutrient levels or composition are more favorable to aphids. When the plant is one that naturally has different elements that would invite in aphids, this would also trigger them to come and infest.

Also, some chemical compounds in plant tissues are known to be attractive to aphids, acting as chemical cues that draw them in. These compounds may include volatile organic compounds emitted by plants, which can signal aphids to locate suitable host plants.

Furthermore, plants that exhibit rapid or vigorous growth are more likely to attract aphids as they provide abundant fresh foliage for feeding and reproduction. And plants with extended flowering periods can also become persistent targets for aphids seeking nectar and pollen sources.

– Tender Growth

Tender growth’s soft and succulent nature is like a dinner bell for brown aphids, signaling them to invade your plants. These pests have a strong affinity for tender plant tissues, making them highly attracted to new growth. The delicate leaves or stems, and even the buds, are rich in nutrients and have a higher moisture content, providing an ideal feeding site for brown aphids.

As plants produce new growth, they release pheromones that signal the presence of fresh, nutrient-dense tissues. These chemical cues draw brown aphids towards the tender growth, guiding them to their next feeding ground. The rapid growth rate of tender shoots also provides a favorable environment for aphids to reproduce and multiply.

– Host Preferences

Brown aphids, like other aphid species, can have preferences for specific plants based on various factors. For example, rose plants’ high sugar content and lush growth make them attractive feeding grounds for these pests. Brown aphids also often infest bean plants, including common, snap, and beans, as they are drawn to the nutrient-rich sap in these leguminous plants’ succulent leaves and stems.

You would often find these aphids on fruit trees, including apples, pears, and peaches, targeting young shoots, foliage, and developing fruit. They can also be problematic for cabbage, broccoli, cauliflower, and other plants in the Brassica family, as well as various ornamental plants, such as daisies and marigolds, especially those with soft, new growth.

How To Get Rid of Brown Aphids From Your Plants?

Get rid of brown aphids from your plants by using organic insecticides, and horticultural oils. You can also place reflective mulch, spread some neem oil, and have natural predators. You must also prune the infested area, have companion plants, and spread diatomaceous earth.

– Organic Pyrethrin-Based Insecticides

Pyrethrins are natural insecticidal compounds derived from chrysanthemum flowers and are widely used in organic gardening. These insecticides have broad-spectrum activity against various pests, including brown aphids, and work by targeting the nervous system of aphids, causing paralysis and killing them.

One of the benefits of these organic pyrethrin-based insecticides is their relatively low toxicity to humans, beneficial insects, and the environment when used as directed. They break down rapidly in sunlight and soil, minimizing any long-lasting impact and making them suitable if you are seeking eco-friendly pest control options. You should apply these insecticides as a foliar spray, thoroughly covering the affected plant parts.

– Horticultural Oils

Horticultural oils, derived from petroleum or plant-based sources, work by smothering and suffocating pests like brown aphids. When applied to plants, they form a thin film that coats the aphids’ bodies, blocking their breathing pores, which would give them difficulty to function.

The aphids cannot obtain oxygen, leading to their asphyxiation and subsequent control. Horticultural oils also disrupt the waxy outer layer of these aphids, causing dehydration and damage to their tissues.

Horticultural oils are most effective when applied during periods of active aphid infestation. Ensure you cover the affected plant parts thoroughly, including the undersides of leaves and new growth. Avoid applying horticultural oils during periods of extreme heat or when plants are under stress to minimize the risk of phytotoxicity.How To Get Rid of Brown Aphids on Plants

– Reflective Mulch

Reflective mulch offers a unique way to control aphids naturally on your plants. This specialized mulch is made of reflective materials, such as silver or aluminum, that create a bright and shiny surface.

This works by disorienting and confusing the brown aphids, deterring them from landing and feeding on the plants. The intense reflection of light created by the mulch creates an uncomfortable environment for aphids, reducing their attraction to the treated area.

The mulch also provides a physical barrier, preventing aphids from accessing the plant foliage. What happens here is that the shiny surface disrupts their ability to land and navigate, forcing them to seek alternative feeding sites elsewhere. Reflective mulch can be applied directly around individual plants or incorporated into the entire garden bed to be effective.

– Neem Oil

Neem oil contains potent compounds that act as insecticides, repellents, and growth disruptors for pests like brown aphids. It is derived from the seeds of the neem tree and works by interfering with their hormonal system, disrupting their growth, development, and ability to reproduce.

When applied to infested plant leaves, neem oil forms a thin coating on the foliage, suffocating the aphids and interfering with their feeding. This helps to reduce their populations and minimize the damage they cause to your plants.

However, it is important to note that neem can harm beneficial insects if sprayed directly on them. This is why you should try to avoid this; hence, it is best applied early in the morning or late in the evening, when these insects are less active.

– Natural Predators

Natural enemies, such as lady beetles, hoverflies, and green lacewings, feed on aphids, helping regulate their populations naturally, providing a biological control method, and reducing chemical interventions. Ladybugs and their larvae seek out aphid colonies on plants, consuming numerous of them during their development stages. For instance, lacewing larvae have sharp mandibles and long, slender bodies that enable them to pierce and kill aphids.

Parasitic wasps are tiny wasps that lay their eggs inside aphids, feeding on them from within once they hatch. You can encourage these predatory insects by growing diverse flowering plants and herbs; try also to avoid using insecticides that harm them.

– Pruning the Infested Parts

Removing heavily infested branches, leaves, or shoots can significantly reduce the brown aphid population and limit their spread to healthy plant parts. When brown aphids infest a plant, they often concentrate in specific areas, such as tender young shoots or the undersides of leaves, providing an opportunity for targeted pruning.

For this, you can directly eliminate a significant portion of the aphid population and remove the source of food and shelter for the aphids, disrupting their lifecycle. Pruning also helps to improve plant vigor, promote new growth and enhance the plant’s ability to defend against future aphid attacks.

However, it is crucial to sterilize your pruning equipment before use and make clean, sharp cuts to prevent further complications.

– Companion Planting

Companion planting is a strategic gardening technique that involves planting certain plant species together to enhance the health and productivity of your garden. However, it can also be an effective method of brown aphid control in the most simple way.

Certain plant species, such as rosemary, thyme, and mint, emit strong scents that aphids find repulsive. Growing these repellant herbs among susceptible plants can create a natural barrier that prevents them from settling and feeding.

Likewise, some plants act as trap crops, attracting brown aphids and drawing them away from the main crops; such plants include marigolds and nasturtiums, as they will also add color to your garden. Moreover, you can grow these plants near your main crops to provide an alternative food source and lure the aphids away before you begin other pest control methods.Get Rid of Brown Aphids on Plants

– Diatomaceous Earth

Diatomaceous earth is a powder with a fine texture made from the fossilized remains of diatoms, microscopic algae with sharp and abrasive shells. When DE comes into contact with brown aphids, it penetrates their protective waxy outer layer and causes tiny cuts and scratches, dehydrating and killing them.

You can use DE by simply dusting it onto the leaves and stems of infested plants, paying particular attention to areas where aphids tend to congregate. You can go ahead and apply this product after the rain or irrigation is important, as moisture reduces its effectiveness, and it should not be used during the pollination season of flowering plants.


As we conclude our journey into the world of brown aphids, let’s take a look back at what we’ve discussed:

  • Brown aphids might attack your plants if they are their preferred species.
  • When your plants are the type that has sugary saps, they will attract brown aphids.
  • When applying any spray, oil, or other organic treatments, thoroughly cover the plant.
  • Avoid using products that can harm beneficial organisms like neem oil, or placing reflective mulch.

So, with your newfound knowledge, you can recognize the triggers of brown aphid infestation in your garden and apply solutions that fit your gardening style.

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