|How canI best treat hybrids suffering from rust spots?|
|Rust is a fungal disease that sometimes affects roses. If rust is a common problem in your area then it is important to plant varieties with good disease resistance -- some varieties are far more prone to infection than others.
Take care to plant them in a sunny area and allow ample space for each plant so they do not crowd each other. (Good air circulation helps prevent fungal diseases.) Avoid wetting the leaves when you water. During the growing season, remove any infected foliage as soon as you notice it and also prune out badly infected canes to try to limit it spreading. Always clean up and remove any fallen leaves from around the roses.
When you do your annual hard pruning, take care to open the center of the plant to light and air. At that time, also strip off all the foliage and clean up all the plant debris around the plants to limit sources of reinfection. Then treat with a sulfur or lime sulfur spray.
I hope this helps!