Organic Management for Rose Fungal Diseases

‘Rose-tinted glasses’, ‘a rose among the thorns’, ‘everything's coming up roses’, ‘stop and smell the roses’, are all everyday phrases that are a testament to the ongoing popularity and prominence of roses among flowering plants. The dazzling petals of a rose in full bloom attract and please home gardeners everywhere and are a reason why people cannot stop planting and growing roses even with all their thorns and susceptibility to deers and pests.

Roses require a lot of attention. No matter how diligent or careful you are, roses are at risk of being exposed to infections and diseases all the time. Fungal diseases are the among the most common afflictions- leaf black spot caused by Diplocarpon rosae, powdery mildew caused by Podosphaera pannosa, and leaf rust caused by Phragmidjum tuberculatum, among others.

The list sounds daunting, but not to worry! Even if each of these different fungal species account for a different type of disease, most, if not all, can be prevented by implementing the following growing practices:

1. Good Air Circulation

Fungi love humidity and mild to warm temperatures. Keeping low humidity around roses is an important first step to take. One way to maintain low humidity is to plant roses with ample space between them, so that they do not get in each other’s way when growing or when fully grown. Next, the plants need to be pruned regularly with sanitized clippers. Pruning not only creates more space between plants, stems, and leaves, but also helps avoid nutrient shortage and encourages healthy growth.

2. Regular Watering

A regular watering schedule is a well-known, but an underrated and underappreciated practice that is crucial to growing a healthy rose bush (or any plant really). Plant roots uptake nutrients through water. Regular watering helps plants consume food whenever it is needed. Plants with sufficient nutrient supplies have a higher chance of maintaining health and a lower chance of falling ill.

3. Preventative Sprays

Applying baking powder suspension, neem oil (limited to cases of powdery mildew), copper fungicide, sulfur, or a bio-stimulant containing either bacteria or fungi every once in a while can significantly reduce chances of getting fungal diseases.

Unfortunately, however, it must be kept in mind that sometimes prevention is not enough to fend off problems:

4. When an Infection is Diagnosed

First, cut off the infected leaves. Remove the infected area and all the fallen leaves in the surrounding area from the site of the infection. This is important, because fungal spores spread to other plants by wind or even by splashing of water, and often occurs over winter from infected leaves that begin to propagate in the Spring.

Next, spray fungicide to and around the plants. This fungicide can be either chemical or organic. An organic solution is always the primary recommendation, but some emergencies could call for the use of chemical fungicides. The spray should be applied thoroughly to both sides of leaves and lower stems. In the case of organic solutions, the spray should be applied repeatedly every 7-14 days.

Some suggestions for organic treatments include copper fungicides, sulfur, or bio-stimulants containing beneficial bacteria or fungi. Some people also recommend baking powder and neem oil as treatment solutions, but in our opinion, these items are better suited for preventative measures.

It is important to keep in mind, however, that although organic measures generally have less negative impact on human health and the environment, they can still be harmful to some extent. For example, an excessive amount of neem oil is toxic to beneficial insects and bees, sulfur and copper irritate eyes and skin, and an overdose of baking soda will change the pH of soil. Accordingly, our primary recommendation for a safer and more efficient treatment is to use both copper fungicides and beneficial-fungi-based bio-stimulants in rotation.

With these tips in mind, all you have to do now is to plant your rose bushes and wait for those beautiful flowers to bloom! In no time at all, your garden will be full of roses in all their glory. Need more information of bio-stimulants ? Drop us an e-mail to info@mikrobs.com.