DISEASE / INSECTS

Insect problems: Aphids, Spider mites. Thrips, Midge.

Aphids: Biggest problem, easiest to control.
Fight them when you see them. Almost any insecticide will do. Orthene is one of the easiest to buy and it is systemic which gives longer control. Insecticide soap is non-toxic, but controls by contact only.

Spider mites: Toughest problem to control. They show up in the hot|-dry summer. They can be washed of with a strong spray of water for temporary control. Check product labels to f ind miticides such as, horticultural oils, insecticidal soups and Vendex Other home garden products include Isotox formula IV (Vendex and Orthene), or Orthonex (Orthene and Funginex).

Thrips: Come in late spring. Spray with insecticidal soap or Orthene (on blooms).

Midge: No-see-em f lies which kill the tips of stems or nip the buds at their base. Stops all further growth of these stems. Sticky traps can Be used to reduce insect populations or if infestations are severe, spray with Arlene.

Disease problems: Powdery Mildew. Rust, Blackspot, Downy Mildew.

Powdery Mildew: As with all diseases, prevention is the key. Prune to provide air circulation and allow sunlight penetration, and provide a fungicide coverage to keep plants healthy. Select varieties that are less apt to be afflicted with fungus diseases. If necessary, start a spray schedule when the disease first appears with an application of fungicide every 7 lo 10 days throughout the growing season. Use Funginex, Wettable Sulfur, or approved fungicide for control. Mildew likes HOT days and cool nights. The disease can develop in relatively dry conditions. Wish it off the leaves with a strong water spray in early afternoon, so plant will dry before evening.
Spores are spread by wind. This cultural practice reduces, but does not eliminate powdery mildew in western Oregon.

Rust: Over winters on diseased leaves and on infected seems. Cool humid weather spurs its growth. Funginex, among others, is registered for spraying. Spores are spread by wind and splashing water.

Blackspot: Over winters on infected leaves. Likes cool wet weather. Must remain on the wet plant for at least 24 hours for infection to occur.
Control with repeated sprays of Captan, Daconil 2787, Fuginex, f ixed copper, Wettable Sulfur, Immunox or other properly labeled chemical.

Downly Mildew: New in our area. Looks somehow like backspot, usually found on the newer leaves, while blackspot usually starts at the bottom of the plant. Spread by splashing water and wind. Occurs in spring, early summer, late summer, and fall. It spreads very quickly and can kill a plant. Control with copper f ungicide applications per label directions.

Also...
Anti- Transpirants: Wilt-Pruf or Cloud Cover are organic materials which may help slow water evaporation during periods of water stress. They may be used with regular fungicide sprays (one Tbsp/gal) or by themselves at label rate.

Spraying: Read the label - before you buy and before you spray! Always use eye protection and mask if label suggests. Also wear long sleeves, pants and gloves made for chemical protection.

Watering: Keep soil around bushes moist by applying one inch of water per week.

pH: Know your soil chemistry. The pH directly affects nutrient availability. Your pH (in western Oregon and Washington) is probably low. Roses grow best at a PH between 6.2 to 6.8 pH. Lime (to supply calcium and raise the PH level) is best used in the fall. Dolomitic limestone has the added advantage of adding magnesium to the soil.

Cultural Controls: Problems can often be avoided by using the following cultural practices. Choose disease and insect resistant varieties, provide good air circulation. Practice sanitation and avoid overhead watering.