How to Get Rid of Aphids on Rose Bushes?
Aphids are tiny, sap-sucking pests and wreak havoc on your roses! They suck out plant juices, preferably on new growths, and turn their foliage yellow and deformed. So, controlling (natural ways) these aphids on roses take time but is worth the effort in the case of heavy infestations. However, early detection of aphids infestation is simple to get rid of during spring and summer. Let’s learn about aphids and how to prevent their infestations on garden roses.
Why Do Roses Get Aphids?
Are All Aphids the Same?
How to Spot an Aphid Infestation on Your Roses?
- Stunted growth with black spots on the rose stem (black sooty mold growth)
- Downward curling of leaves
- Yellowing of leaves due to chlorosis and reductions in flower quality
How to Prevent an Aphid Infestation?
- Regularly monitor the rose plants for aphids, mainly on the underside of leaves, for early detection at least twice a week.
- Prune off the old, weak, and damaged leaves and branches to destroy the overwintering eggs before the bud break.
- Use a garden hose with high streams of water on the underside of leaves to kill and wash off the rose aphid infestations (adults and larvae). Repeat every 3 to 5 days to destroy the aphid population.
- In the case of minor populations, remove the aphids manually with the help of a soapy water spray (liquid dish soap and water), neem oil, or other insecticidal soap.
- Encourage growth of beneficial insects for your rose bushes. Aphids have many natural enemies, including parasitic wasps, green lacewings, lady beetles, and hoverflies.
- Aphid predators will feast on all stages (eggs, larvae, and adults) of this pest and prevent their large numbers of infestations in home gardens.
- The presence of ants near the rose plant can indicate an aphid infestation. So, managing black ants is critical in preventing large numbers of aphids because ants tend them and protect them from natural predators. To control ants, put a band of sticky material such as tanglefoot around the rose stem to prevent the climbing.
How to Kill Aphids on Roses?
Conventional Means With Chemicals
- Keep your rose garden clean, and remove any fallen, dead, and damaged rose leaves as they may provide them hiding place to overwinter
- Cut out your rose plant's curled, twisted, and discolored leaves and adequately discard them because they may spread aphids to other healthy rose plants. Do not put these pruned plant materials into the compost pile (it may contaminate the natural fertilizer).
- Do not overfertilize your rose plants with a nitrogen fertilizer to support the new leaf growths and aphid reproduction. Instead, apply an organic and less soluble form of nitrogen fertilizers such as urea-based in smaller amounts throughout the growing season.
- Keep an eye for weeds or alternate hosts such as mustards and sowthistle that may attract aphids into your rose garden. Remove these weeds before spring or the growing season to control infestation of aphids.
- Use reflective mulches such as silver-colored to repel the invading populations of aphids and reduce their damage to new growths and flower buds. To settle the mulch in your garden, remove the weeds, cover the plant beds with silver covers, and bury their edges to keep the sheets in place. These silver mulches will repel the aphids and improve the growth of rose bushes by reflecting sunlight onto leaves.
- Along with silver reflective mulches, spray rose plants with insecticidal soap to deter the aphids. Reapply this weekly for the best results.
- Another best and natural insecticide to kill aphids is soap water spray. Apply mild dilutions of soapy water, particularly on the underside of leaves, weekly.
- One of the best and must-use insecticides in gardens is “rose systemic” (Disyston) to kill aphids, leafhoppers, and thrips.
- Use petroleum-based horticultural and plant-based oils such as neem oil and canola oil. These oils suffocate the aphids and instantly kill them. Neem and horticultural oil sprays provide pest control at all stages within their life cycle and need repeat applications.
- Insecticidal soaps such as Safer soap spray provide effective aphid control in rose plants. Applying these insecticidal soaps helps gardeners get rid of low and high aphid populations quickly. These soaps penetrate the hard outer covering of the insect body and cause death due to dehydration. These insecticidal l soap sprays are better for pollinators and other beneficial garden birds (also non-toxic to humans, pets, and children).
Bringing Predatory Insects to Your Garden
- Parasitic wasps deposit their eggs within the aphid, and developing wasp larvae feed on the body fluids of these garden pests, thus killing them.
- Ladybugs are the aggressive predators of aphids and whiteflies. They primarily feed on all stages of aphids, including adults, young, and eggs, and keep the aphid populations in control.
- Hoverflies (the larval stage of syrphid flies) are a significant predator of aphids and actively feed on them. They are often present in the colonies of aphids as legless larva and control the aphid colonies.
- Green lacewings also effectively control the aphid population in rose gardens because their adult and larvae actively feed on aphids and other soft-bodied insects.
Why is Controlling Aphid Important?
- Aphids prefer to feed on plant sap and suck it out by piercing mouthparts from the phloem tissues. The more sap these bugs suck, the more rose plant loses their vigor against invaders. At the same time, they excrete this sap in a sticky substance (honeydew) which supports the growth of black sooty mold fungus and ants.
- Black sooty mold fungus spreads over the entire leaf surface and causes black spots, thus compromising the cosmetic value of leaves and the whole plant.
- They breed sexually and asexually and have many generation cycles during the growing season.
- Aphids are challenging to control because they overwinter as eggs or adults in weeds and other plants.
- Aphids transmit many plant viruses in perennial flowers and vegetables, such as a rose yellow mosaic virus (RoYMV) and rose mosaic virus (RMV)—caused by aphid transmitted viruses. That’s why the control of aphids on roses is essential.