Roses are one of the most popular perennial landscape plants. They thrive wherever there are warm summers, frequent rainfall, and moderate winters. Unfortunately, ample rainfall and warm summers are also favorable conditions for pests.
The most common problems that can affect your rose plants are aphids, black spots, powdery mildew, and rose rust. Aphids attack my rose bushes nearly every year. Even though I regularly spray my garden with insecticides, these aphids always seem to find their way back into my garden.
So, what exactly are aphids and how can we get rid of them? Keep reading to find out!
Aphids
Aphids are tiny, soft-bodied insects that appear in a wide range of colors: yellow, light green, pink, red, brown, and even black. Most aphids have a woolly exterior coating, an elongated pear-shaped body, long antennae, and a pair of structures called cornicles, which look like exhaust pipes protruding from the hind part of their bodies.
Aphids prefer to attach to young shoots and feed on plant phloem. Phloem is a plant tissue made of specialized cells that transport food from the leaves to the rest of the plant. Aphids use specially adapted mouthparts, called stylets, to pierce the plant tissues and reach the phloem, which they feed on to assimilate the soluble organic nutrients present in it.
Aphid Reproduction
Unlike other insects, aphids have a unique way of increasing their population and the size of their colonies. Their reproduction moves back and forth between asexual and sexual phases, controlled by seasonal changes. Once the spring arrives, fertilized overwintering aphid eggs hatch into wingless females. These attach themselves to a host plant and feed on its sap. Once mature, these wingless female aphids reproduce asexually, giving birth to live clones. This asexual reproductive phase continues throughout summer.
At the end of summer, the aphids will switch into a sexual mode of reproduction. Male aphids will mate with the female aphids. The females will then produce several hundred fertilized overwintering eggs. These overwintering eggs stay in the soil and hatch after the winter ends.
The Impact of an Aphid Infestation
As the aphid colony increases in size, the health of the host plant will rapidly deteriorate. Aphid-infected flowers and fruit become distorted. Aphid-infected leaves turn yellow and begin to wilt or curl. These pests also excrete a sugary liquid called honeydew, which sticks to plants and attracts ants. On top of that, honeydew also encourages the growth of a mold that makes the plant shoots appear black and sooty. Once stressed, these plants will also be more likely to fall victim to several secondary infections and may eventually die if the aphid problem isn’t treated in time.
How to Get Rid of Aphids on Roses: Control & Preventative Measures
You can apply any of these aphid infestation prevention and control strategies, depending on the needs of your garden and how bad the aphid infestation is. For serious and/or recurring infestations, either use a combination of these strategies or seek help from a professional pest control company.
Prune infested plant shoots
Start simple. Cut off all branches showing signs of an aphid infestation, such as wilted and curled leaves. When pruning these branches, make sure that the infected branches don’t land on an adjoining healthy branch or a nearby healthy plant. You definitely don’t want to transfer the aphids to new host plants. Carefully discard the cut portions of the plant in a yard waste collection bag. Store that bag as far away from your plants as you can.
Spray shoots with water
Spray your infected rose shoots with a jet of cold water to dislodge the aphids from the plant. Repeat this process every few days to remove any traces of aphids from your roses. Focus on the undersides of leaves because that’s where aphids tend to hide. It’s best to do this in the morning to leave enough time for the leaves to dry during the day. If you leave a plant moist overnight, the leaves could develop fungus.
Dust your plants with flour
Dust your rose plant with a generous amount of flour. The aphids will ingest the flour, but they can’t digest it. The undigested flour clogs their digestive system, resulting in death. This approach is especially useful when your rose bush is young and can’t withstand the force of a powerful jet of water. You can also use the flour dusting strategy when the aphid infestation is on flower buds or young shoots.
Use a mild dish soap solution
Spray the leaves of your roses with a mild dish soap solution. Do this once every two to three days, continuing for at least two weeks. You can also wipe the leaves with the solution instead of spraying it on.
Try using insecticidal soap
People also often spray diluted insecticidal soap solutions on their roses to get rid of aphids. The labels on these products often claim that they don’t harm beneficial insects. Well, the truth is that insecticidal soaps, once used in a garden, affect all insect species. So, refrain from using this option for milder infestations that you can treat using other methods.
Introduce natural predators
Ladybugs, green or brown lacewings, blister beetles, soldier beetles, damsel bugs, midges, and hoverflies are all natural aphid predators. You can buy a small bag of these beneficial insects and introduce them into your aphid-infested rose garden. They’ll rapidly devour the aphid colonies on your rose plants, effectively getting rid of your aphid problem and leaving your plants healthy and thriving.
Kill overwintering eggs
Spray neem oil, horticultural oils, or other environmentally-friendly oils on the soil in your garden in fall. This will help kill the aphid’s overwintering eggs.
Keep aphids away using companion planting
If you don’t currently have an aphid infestation but want to prevent any future aphid infestations, one good preventive strategy is to plant catnip, garlic, or chives near your rose bushes to deter aphids. Growing certain plants, which either repel pests or attract pollinators, close to other plants is known as companion planting.