Roses are one of the most popular ornamentals plants grown for the retail market because of their range of shapes, sizes and colors. This variety makes them suitable for growing as cut flowers, in containers for the patio or for transplanting to the garden.

Production occurs throughout the year, making the plant susceptible to many different insects and diseases depending on the season. Mites, downy mildew and powdery mildew, for example, can affect roses from spring through fall. Preparing for these pressures before they develop can help you limit their spread while producing high-quality crops.

Common threats

Spider mites, including the two-spotted spider mite, feed mainly on the underside of the plant leaf surface, using their stylets to penetrate plant cells and suck out their contents. Damage is first observed on leaf tissue as pale green mottling due to the loss of chlorophyll from damaged cells. With continued feeding, leaves turn yellow with some brown areas.

Downy mildew can severely impact the production and sale of roses, which is why recognizing early signs of the disease is critical to plant quality and health. Leaf discoloration or spotting, often within the veins, are the most common initial symptoms. Symptoms to look for include pale foliage with yellow, tan or reddish blotchy areas, distorted or downward curling leaves and light gray or purple fuzz on the undersides of leaves.

Powdery mildew fungi form white, talcum-like spots called “colonies” on leaves, stems and flowers. Over time, these colonies increase in size and number to cover the plant’s surface. If not controlled, severe infections will cause leaves to turn yellow, brown and then drop, resulting in reduced plant vigor and growth.

Establish proper cultural practices and use an agronomic program

Whether your production area is a greenhouse or outdoor nursery, it’s important to provide proper spacing between plants to allow for good air flow. This helps reduce humidity levels within the plant canopy and the incidence of foliar diseases. Regularly scout for diseases and insects, checking throughout the canopy of plants and the undersides of leaves for symptoms.

Along with proper cultural practices, using effective plant protection tools can help keep plants healthy and looking their best. An agronomic program such as this one from Syngenta, provides a framework for rotating products to leverage their strengths and modes of action. Complete with product application and timing recommendations, an agronomic program will help set you up for successful rose production indoors and out.

Learn more about Syngenta agronomic programs at GreenCastOnline.com/Solutions.

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