If you are having problems with your roses, insects may be responsible. They can do a lot of damage if you do nothing to chase them away. Here is an overview of ten creepy crawly enemies of roses and some ways to identify them.
Aphids are the most frequent problem pests. They like to make themselves at home in the growing tissue of roses (buds and shoots). Low or even moderate levels of aphids will pose little threat to your roses, though you will need to keep a close eye on how they spread. High numbers of aphids produce an excess of honeydew, which will encourage the growth of mold and they will eventually blacken the rose leaves.
If you have very high numbers of aphids, the size of the flowers may diminish and buds may be killed. There are some natural enemies to these pests, including lady beetles and syrphid flies. The creatures will help keep the population growth under control. You can try removing them from the roses with a spray of water or with insecticidal soaps. Aphids are usually only a problem during the spring and early summer and usually you do not have to resort to insecticides to control them.
2. Spider Mites
If your rose leaves are stippled or dried up and falling off, then spider mites may be the problem. Spider mites are so tiny that you will probably need a magnifying glass to spot them. Their presence is usually the result of dry, dusty conditions. You can try to control spider mites by reducing dust and ensuring that your plant has sufficient irrigation.
3. Fuller Rose Beetles
Adult beetles will chew away at the flowers and leaves of your rose bush. You can usually detect their presence by the ragged edges of your blooms and foliage. They feed during the night and hide during the day on the underside of leaves. Pesticides are not effective in dealing with these insects, so the best solution is handpicking these beetles off.
Thrips damage the blooms by leaving brown streaks on the flowers. They are a huge problem when rose bushes are planted close together because they can move quite easily from one plant to another. They are usually attracted to light colored or white roses and cause a great deal of damage. It is difficult to control thrips with pesticides because they are really only effective at the development stage. The best thing to do is clip and dispose of infected blooms.
There are some types of caterpillars that will feed on rose leaves. Usually the damage is not that threatening to the rose plant. Simply remove the rolled leaves and prune any damaged buds.
5. Rose Slug
These are the larva of a sawfly, but they resemble caterpillars because they have legs. You can wash these off with a forceful spray of water or let one of their natural enemies take care of the problem for you.
7. Leafcutter Bees
Leafcutter bees make semicircular holes in leaves and take this material back to their nests. You’ll just have to put up with this, as there is no effective way to combat them other than killing the leafcutter bees. It is recommended that you don’t kill bees since they are natural pollinators.
8. Rose Curculio
Rose Curculios prefer yellow and white roses. They are about a quarter of an inch long and go about punching holes in the flowers and buds. The larvae feast on developing buds so the buds are killed before they even get a chance to open. If you have an infestation of rose curculios, you can rid them by using an insecticide from your local home or garden center.
9. Flat headed Borers
Flat headed borers can cause the canes to die back. They may kill canes or the entire rose plant. You need to remove any material that is infested with these critters and keep the plants healthy by not over pruning in the summer months and ensuring there is sufficient irrigation.
10. Scale Insects
Scale insects also pose a threat to the canes. Scale insects have armored scales and look like small, grey rounds or ovals. These creatures don’t really move because they have no legs for most of their lives so they are there to stay once you spot them. The best way to combat scale insect infestations is to prune away infected canes and put some pesticide oil on any remaining canes.