Pests and diseases in rose bushes: aphids, black spots

Hello farmers! Surely we all have in mind a person to whom we would give a bouquet of roses And…, what better way to do it than with some roses grown by ourselves, right?! In today’s article, we will give you some tips to identify, prevent and treat the most important pests and diseases of rose bushes. In this way there will be no more excuses to get beautiful and healthy roses.

I remind you that when we talk about plague, we refer to a group of arthropods (mites, insects, crustaceans,…), nematodes or other types of animals that are causing damage to our crops. However, when we use the term disease, we refer to: fungi, bacteria or viruses.

Pests on rose bushes

The main pests that we can find in rose bushes are the following:

Aphids on the rosebush

Aphids, aphids,… They are everywhere! For this reason, they are considered to be one of the most common pests in orchards and gardens. Our rose bushes will not get rid of them either. They are small insects between 1-3 mm. And, although the most common are green, they can have other colors depending on the species.

Most are polyphagous, that is, they have no preference for a specific plant species. They attack the young shoots of crops with a high sugar content. The larvae cause damage by making galleries in the leaves of plants. As for adults, they feed by sucking sap from leaves, buds and young shoots using the stylet of their mouthparts. In addition, they excrete a sticky, sugary liquid called honeydew that attracts ants (which is why many times where you see aphids, you will see ants).

Sometimes, they favor the appearance of a fungus known as bold and can also transmit viruses from one plant to another.

Control measures against rose aphids:

• Prune the most affected shoots or remove aphids using a small brush.
• The main natural enemy of aphids is ladybugs. If you put ladybugs in your orchard or garden, they will keep aphids at bay!
• Pour soapy water over the aphids.
• Infusion of garlic or onion.

Here I leave you a photo of a ladybug that I caught the other day in my rosebushes about to eat the aphids present.

For more information, I recommend that you read the article on how to control aphids.

Little red bugs on the rosebush: spider mite

Although it is known as a spider mite, it is a species of mite. Remember that we should not confuse mites with insects. Mites have 8 legs, unlike insects, which have 6. They are located on the underside of the leaves and are identified by having dark spots on the sides and a large number of silks.

As for its control, I leave you a link where we explain how to fight the red spider in the orchard.

caterpillars on rose bushes

The most common is the rose bush caterpillar (Arge rosae). It is called that because it is not actually a caterpillar, but the larva of a kind of wasp.

These false caterpillars measure between 7 – 10 mm and feed on the leaves, which is why they cause defoliation (destruction of leaves), which can seriously damage the rosebush.

Treatment: there is no specific product for this pest, what is used are broad-spectrum insecticides, which you can find at your favorite garden store. These insecticides also serve to kill other insects that attack rose bushes, such as aphids, which we have mentioned before.

If there are not many, they can also be removed by hand.

Other bugs in the rose bushes

In addition, there are other insects that can affect our rose bushes, such as the cottony mealybug or some species of caterpillars.

Rose diseases

Among the main diseases of rose bushes, those caused by fungi stand out:

Spots on the leaves of roses: La Roya

Rust is one of the most important fungi, along with powdery mildew. It needs mild temperatures and high humidity to thrive. It usually appears after long periods of heavy rain. It is very easy to identify it: you have to look if there are orange bumps on the underside of the leaves and small yellow spots on the upper side.

White spots on rose leaves: Oidium

This fungus appears in the form of white spots and gradually transforms into a grayish-white powder. Thanks to that white powder, it is one of the easiest mushrooms to spot. It normally develops on the upper surface of the leaves, although it can also spread along the stem or the fruits. Their presence hinders photosynthesis. If we do not control it well, the leaves turn yellow and can dry out.

Humidity and warm temperatures are the ideal conditions for powdery mildew to appear in our garden.

I leave you an article where we talk about how to control powdery mildew.

Black spots on rose leaves: Marssonina

If round black spots appear on the leaves of your rose bushes… it’s marssonina. In the event that the infection is very advanced, it can cause defoliation (fall of the leaves). It requires a mild temperature and the presence of water, since it is spread by rain splashes.

The best way to eliminate it is to remove the affected leaves and destroy them. Some people recommend mixing two parts of milk with one part of water and pouring it on the leaves with the help of a spray.

Control fungus on rose bushes

Do not miss the article on prevention and ecological treatments for mushrooms in the garden.

Finally, I leave you an image that I find very illustrative and can serve as a summary of the article.

References

• Leus, L. (2017). Selection Strategies for Disease Resistance in Roses. Reference Module in Life Sciences, Elsevier.
• Hegelund, JN, Lütken, H., Müller, R. (2017). Postharvest Physiology: Ethylene in Roses. Reference Module in Life Sciences, Elsevier.
• Braun, U. (1980).Morphological Studies in the Genus Oidium. Flora. 170(1–2), 77-90.

That’s all for today, I hope you liked the article and that you don’t want to give away that bouquet of roses.

Have a nice day!