{"id":188,"date":"2026-02-26T22:50:39","date_gmt":"2026-02-26T22:50:39","guid":{"rendered":"https:\/\/www.coltivobio.com\/en\/?p=188"},"modified":"2026-09-06T21:30:41","modified_gmt":"2026-09-06T20:30:41","slug":"all-rose-diseases-with-images","status":"publish","type":"post","link":"https:\/\/www.coltivobio.com\/en\/all-rose-diseases-with-images\/","title":{"rendered":"All rose diseases: practical guide with images"},"content":{"rendered":"

Like all plants, the rose is subject to attacks by pests and diseases caused by fungi and insects. In this practical guide, we provide a general overview of the phytopathologies that damage roses. For each disease or insect, you will find a link leading to a more detailed description, since this technical sheet cannot cover every topic in full. We therefore encourage you to explore the topics that interest you by clicking the relevant links. To help with quick identification, each disease or insect is described with photos and images. The technical sheet is divided into two sections: disease agents (fungi) and damage agents (insects and mites).<\/strong><\/p>\n

Disease Agents: Fungal Diseases<\/strong><\/h2>\n

Roses are affected by a wide range of fungi. Below we analyze the most important ones and the remedies used for prevention and treatment. At the end of this section you will find a list of the main fungicides used on roses.<\/p>\n

Rose Black Spot<\/strong><\/h3>\n

Rose black spot<\/a> is among the most common rose diseases and is easily identifiable, although inexperienced observers may confuse it with rose downy mildew<\/a>. Black spot is caused by the fungus Diplocarpon rosae<\/em> and appears on leaves as roundish spots with irregular edges. These spots are charcoal black or sometimes dark gray. In many cases, the spots show a network of veins radiating from the center outward.<\/p>\n

\"black<\/p>\n

As symptoms progress, leaves lose color and sensitive rose varieties may become completely defoliated.<\/p>\n

Preventive measures include removing infected plant parts and keeping them away from the garden. Avoid overhead irrigation, since humidity plays a key role in disease development. Copper-based<\/a> products are the main preventive treatment. Sulfur<\/a> has a weaker secondary effect and is mainly used against powdery mildew. In areas highly favorable to the disease, rose varieties tolerant to black spot should be preferred. Soy lecithin can also be used as a strengthening agent to increase plant resistance.<\/p>\n

For the complete technical sheet on this disease and additional solutions, we invite you to read our full technical Rose black spot (here).<\/strong><\/a><\/p>\n

Rose Downy Mildew<\/strong><\/h3>\n

This plant disease is caused by the fungus Peronospora sparsa<\/em>, which attacks cultivated roses and various Rubus species such as blackberry and raspberry. It is one of the most difficult rose diseases to diagnose because it is often confused with black spot.
\nDowny mildew causes necrotic spots on leaves, ranging in color from purple-red to brown or black.<\/p>\n

\"sintomo
Source image Plant Disease 2018 here the link<\/a><\/figcaption><\/figure>\n

In Peronospora sparsa, the spots are typically angular and confined between the main leaf veins, whereas black spot lesions are circular with ragged edges and tend to merge.
\nThis disease requires high humidity to develop and is therefore more common in greenhouse cultivation than outdoors.
\nPreventive measures are the same as for black spot, including copper treatments.<\/p>\n

For the complete technical sheet on this disease and additional solutions, we invite you to read our full technical guide on rose downy mildew (here).<\/strong><\/a><\/p>\n

Powdery mildew of rose<\/strong><\/h3>\n

Powdery mildew is a fungal disease caused by Sphaerotheca pannosa<\/em> var. rosae<\/em>. It affects roses and other plants in the Rosaceae family.
\nIt appears on green tissues as a white, felt-like mycelial coating resembling mold, initially accompanied by discoloration of affected parts. In advanced stages, infected tissues dry out or become severely deformed.<\/p>\n

\"sympotoms<\/p>\n

Control measures include removing fallen leaves, including those from previous seasons, as the fungus overwinters in plant debris. During winter pruning, stems that showed symptoms the previous year should be removed.
\nPreventive sulfur treatments remain one of the main control methods. Natural remedies include sweet orange essential oil and zeolite. Potassium bicarbonate<\/a> is effective but generally less so than sulfur. Soybean oil, although primarily an insecticide, also has a secondary effect against powdery mildew.<\/p>\n

For the complete technical sheet on this disease and additional solutions, we invite you to read our full technical guide by clicking here<\/strong><\/a>.<\/p>\n

Rose rust<\/strong><\/h3>\n

Rose rust<\/a> is a common disease and is considered the third most serious fungal disease after black spot and powdery mildew. Affected plants develop small amaranth-red spots on the upper leaf surface, surrounded by a lighter yellowish halo. On the underside of the leaves, orange pustules form near these spots, becoming powdery at maturity.<\/p>\n

\"symptoms<\/p>\n

Symptoms may also appear on petioles and young stems. The disease is caused by several fungi belonging to the genus Phragmidium. Infected leaves show spot discoloration and lose photosynthetic capacity. Severely affected plants have poor aesthetic quality and produce fewer flowers.
\nSeveral chemical products are registered for control, including copper-based organic formulations, which are preventive. Among strengthening agents, soybean oil can stimulate plant defenses and also help control red spider mites.<\/p>\n

For the complete technical sheet on this disease and additional solutions, we invite you to read our full technical guide on rose rust (here).<\/strong><\/a><\/p>\n

Brown canker of rose<\/strong><\/h3>\n

This disease is caused by the fungi Coniothyrium wernsdorffiae<\/em> and C. fuckelii<\/em>. These fungi cause stem cankers. Affected tissues turn brown, collapse, and develop a hazelnut-like coloration.
\nThe infection causes death of tissues above the entry point of the pathogen. After cankers appear, young shoots die and leaves above the affected area wilt. In advanced stages, black dots called pycnidia form on the canker surface; these are fungal reproductive structures that release spores and spread the disease.<\/p>\n

\"Typical
A rose branch showing symptoms of canker.<\/figcaption><\/figure>\n

The disease is favored by rainy and humid conditions. The pathogen enters through wounds, especially pruning cuts. Prevention consists of disinfecting pruning tools and applying preventive copper treatments. Infected plant parts should be removed or burned. Control is mainly preventive, since no fungicide can stop the fungus once established inside the plant.<\/p>\n

Fungicides used on roses<\/strong><\/h2>\n