Noticing more and more misshapen leaves in your rose garden lately? Are your rose leaves starting to curl downwards, or turning yellow? Well, you most likely have aphids perched on your rose bushes!
Roses are a popular home garden plant due to their vibrant and fragrant blossoms. However, keeping them healthy and thriving can sometimes become a challenge, as they’re vulnerable to a variety of pests – aphids being one of them. These tiny insects can easily cause damage to your rose bushes once they invade the plants to feed on the plant sap.
If you’re looking for solutions to the aphid infestation in your backyard rose garden, you’ve come to the right place! This guideline will take you through how to know your rose bushes are aphid-infested, which type of aphids they’re most likely to be, what kind of damage aphids cause to roses, and what you can do to get rid of aphids or prevent them from invading your rose bushes.
What type of aphids infests roses?
Rose plants are vulnerable to roughly 30 species of aphids. However, of the 30 species, the common rose aphid (Macrosiphum rosae) is the most prolific rose garden invader. Rose aphids have a characteristic green/pink shade. This aphid species is not only the most common in rose bushes but also the most damaging to the flowering plants; as they feed on young blossoms- leaving them with a contorted and twisted appearance (The sap-sucking aphids inject digestive saliva into the shoots, which initiates digestion, resulting in the contorted look).
Another factor that makes common rose aphids so dangerous to your roses is the fact that they’ll stay perched on your rose bushes all year round if not dealt with. Second to common rose aphids are melon aphids (Aphis gossypii), which bear a distinctive dark-green shade that turns yellow around mid-summer.
Another notorious rose plant pest is the hairy rose aphid, which likes to feed on the sap of rose bus and shoot tips. Other common aphid species that are likely to invade your roses include the rose-grain aphid (Metopolophium dirhodum) and the giant rose stem aphid (Maculolachnus submacula).
The frequency with which aphids will invade your rose garden depends on what kind of roses you’re growing. The following rose plant species are known to be the most susceptible to aphid infestations:
- Rugosa roses.
- China roses.
- Prairie roses.
- French roses.
Signs of aphids on rose bushes
It’s important to identify aphid infestations in the early stages and consequently undertake control measures. This is because when the aphid populations are still low, the damage to roses is negligible. You can check for aphid invasions by inspecting the leaves for the presence of dark, sooty mold fungi. The growth of such unsightly mold fungi on rose foliage is typically encouraged by honeydew- aphid excrement. Honeydew also attracts wasps and other aphid predators. Therefore- if you spot wasps flying above your roses- chances are you have aphids on your rose foliage.
You can also confirm an aphid infestation by directly identifying the small ants. Despite being barely visible to the naked human eye, you can easily identify these pests with a magnifying lens. Most aphid varieties are green-colored, pear-shaped, and range anywhere between 1/16-inches to 1/8-inches long. However, it’s not uncommon to find pink, yellow, brown, or mottle-colored varieties perched on your rose bushes. These notorious plant pests are also wingless.
How to get rid of aphids on roses
Physical removal
You can physically dislodge aphids off your rose bushes by brushing them off the stems and leaves. Alternatively, you can flush off the rose foliage with a jet of water. Since they’re slow-movers, it’ll be difficult for the dislodged aphids to climb up your rose plants again.
Finally, if the aphid infestation is still at its initial stages, you can prune off the few, affected leaves and prevent the damage from reaching the rest of the foliage. Since aphids are wingless, slow-movers, they cannot run or fly off to adjacent leaves as you prune the leaves on which they’re perched.
Biological controls
Biological control entails using aphids’ natural predators to control their populations in your rose garden. There are multiple ways to approach biological control, as detailed below:
- Conservation Biological Control
This is when you establish the right conditions within your rose garden to attract aphids’ natural predators. For instance, if you want to attract blue tits into your rose garden to feed on aphids, you can set up nest boxes for them within the rose garden. Another proper example of conservation biological control is when you plant blue tansy as a rose companion plant to attract hoverflies- which like to prey on aphids.
Mature hoverflies require nectar for energy and pollen to spur egg development- and blue tansy is a good source of both nectar and pollen. When planted alongside roses, the hoverflies will not only feed on the blue tansy nectar and pollen but also the aphids perched on the adjacent rose bushes.
- Inundative Releases
This is when you mass-release aphid predators into your rose garden at periodic intervals to prey on the aphids that are causing damage to your rose bushes. You can always purchase common aphid predators such as hoverflies, wasps, and ladybugs from the numerous agricultural brands that specialize in breeding these insects in captivity and selling them for use as beneficial insects.
Use of chemical insecticides
There are- however- two major downsides to using chemical insecticides to get rid of aphids in your rose garden. First, they kill off beneficial insects like wasps and ladybugs as well. Second, chemical insecticides are toxic and may harm your rose leaves if not diluted to the right concentrations.
To properly get rid of aphids on roses by spraying with a chemical insecticide, follow the procedure below:
- Wear a pair of gardening gloves, and a surgical face mask, especially if you’re allergic to the smell of chemical fumes.
- Next, dilute the insecticide as per the manufacturer’s instructions, and transfer the solution into a gardening spray can.
- Now, spray your rose bushes, ensuring to target the underside of the leaves where aphids tend to hide out. If possible, use a fine-jet nozzle that will release fine streams directly onto the rose leaves that you’re targeting.
- Repeated spraying is almost always necessary for maximum efficacy/ to ensure you get rid of all aphids.
Use vinegar spray
To effectively kill aphids on your rose plants using vinegar, follow the procedure elaborated below:
- Fill a spray bottle with distilled white vinegar and water in a ratio of 1:2.
- Spray the vinegar solution directly onto the rose bushes. This is one of the most effective natural aphid remedies on this list, as it kills aphids and their larvae as soon as they come into contact with them
Apply dish soap solution
To effectively destroy aphids on your rose bushes using a dish soap solution, follow the procedure detailed below:
- Pour a liter of water into a bucket, then add two drops of dish soap. Organic dish soap- and not detergent dish soap- is recommended. Note that the number of drops may be more or fewer depending on how concentrated you need the solution to be.
- Next, stir the mixture and transfer the solution into a garden spray can.
- To test how powerful the particular brand of dish soap you’re using is and determine how concentrated you’ll need the solution to be, apply the solution to a couple of rose leaves and observe the effects. If there’s visible damage on the rose leaves, you’ll have to dilute the solution by adding a bit more water- before spraying all your roses.
- Now, spray the solution all over your rose bushes to entirely get rid of the aphid colony. Remember, spraying of dish soap solutions on rose gardens should be done early in the day when the weather is still cool, as the combination of hot weather and the solution can trigger leaf scorching.
Neem oil
Neem oil is another effective, natural aphid killer when applied repeatedly. It’s especially useful in getting rid of white aphids on your roses. The main upside to using a natural pesticide like neem oil to destroy aphids is that it won’t harm beneficial insects, as is the case with chemical-based insecticides. It’s also non-toxic to pets and humans. To effectively use neem oil to get rid of aphids on your rose bushes, follow the procedure outlined below:
- Mix neem oil with water in a bucket. You can boost the solution’s potency by adding a couple of drops of organic dish soap. Then, transfer the solution into a garden spray can.
- Spray your rose garden leaves, stems, and blossoms to get rid of all aphids. Target the nozzle at the leaf undersides as well, as this is where aphids love to take cover.
- To get rid of all aphids, you should repeatedly spray neem oil solution on your rose bushes. You should- however- mix a fresh batch each time you intend to spray. This is because it breaks down after a few hours, after which it loses its efficacy.
- You may also want to lay off direct irrigation of your rose foliage after applying neem oil to avoid washing off the pesticide solution.
What damage do aphids cause to roses?
Aphids have sharp mouthparts which they use to bore through rose plant tissue, consequently draining the tissue sap off the plant. This, consequently, causes the rose foliage to curl downwards, shrivel, wilt, and become discolored. Eventually, if not controlled, the aphid populations grow to levels high enough to cause plant death by feeding on too much plant sap.
Meanwhile, the mold fungi growth facilitated is usually an eyesore. What’s more, the mold fungi usually form black mats that form a blockade that prevents sunlight from reaching the surface of your rose leaves. This then interferes with photosynthesis and could hinder plant growth in the long run.
To safeguard your rose bushes against such pest damage, ensure to maintain the proper environmental conditions for your roses. This is because a thriving rose plant has higher chances of making it through pest damage, compared to a stressed rose plant.
Another preventive measure is to use a slow-release fertilizer or organic compost, both of which will release nitrogen to be absorbed by the rose plants at gradual intervals. This helps because aphids are more attracted to nitrogen-rich roses. The pests use nitrogen to support reproductive processes. As such, a slow-release fertilizer prevents the absorption of excess nitrogen by the roses, which in turn attracts aphids.
References:
[1] https://www.rhs.org.uk/advice/profile?pid=697
[2] https://hgic.clemson.edu/factsheet/rose-insects-related-pests/
