Mites are the third member of the team that is out to get your garden (fungus, insects, mites). These critters are a difficult problem once they are established, but there are steps that can be taken to ensure they don't get comfortable in the rose garden.
The mite that we deal with most often is the Two Spotted Spider Mite. Spider Mites are in the arachnid family and are almost invisible to the naked eye. They can easily be seen with a magnifying glass and unfortunately the results of their feeding on your roses can be seen easily with the naked eye.
Spider Mite Symptoms
Generally leaves will lose their brilliant green color and become faded and brown. You can often see their webbing on the underside of the leaves.
The underside of the leaves will also look dusty because of the dirt and debris that get caught in their webs.
What Can I Do?
Keep the roses watered - The best way to avoid any issue is to keep your roses healthy. In the heat of the summer rose bushes need 5 gallons of water per plant per week. Well watered bushes will be able to handle any stress, including Spider Mites, better than thirsty plants.
Use your hose - If you check the bottom of the leaves and see that you are beginning to get spider mites, spray the tops and bottoms of the leaves with your hose. I know this seems counter-intuitive because leaves are supposed to be dry as much as possible, but the spray from the hose knocks the Spider Mites off the bush and they cannot crawl back on. Make sure to do this in the morning so the bush can dry off and keep up with your fungicide application.
Miticides - There are several miticides that are available to homeowners to help control mite problems. Products such as Avid, Neem Oil, and pyrethrin based sprays are effective to reduce the spider mite colonies. These should be used in conjunction with the steps listed above for greatest effect.
Keep in mind that if your garden is next to brick or surrounded by rock or concrete you may have more mite difficulties. These surfaces hold heat well causing a very warm microclimate that mites love. Wash down these surfaces with water as much as possible.
Spider Mites can cause you major headaches in your rose garden. However, with a little bit of diligence and a lot of vigilance you can keep them out and keep your roses beautiful.