Aphids, fungus, and cotton?
Hello, My Aspen trees and rose bushes in particular seem to be infested with aphids, white powder fungus, and what looks like cotton fibers on the leaves and rose buds. Should I hire someone to come and spray the trees and bushes or can I treat them all myself? I have a young daughter so I am interested in the safest options. Thanks, Brittany
Arapahoe County Colorado trees and shrubs
You can safely treat the aphids and powdery mildew. I'm not sure what the cotton fibers are. Can you send a picture?
Aphids: The easiest and one of the most effective treatments is a strong water spray from the hose. Aphids are quite fragile and will die or be unable to climb back to the rose or aspen. You will need to spray the affected plants at least once a day to see fewer aphids. I suggest spraying in the morning as you have a powdery mildew problem, which will be increased if water sits on the leaves for an extended period (like overnight).
Powdery mildew: This fungi needs high humidity to germinate. It is best controlled with preventive practices such as resistant cultivars, good air circulation and removal of dead leaves and debris in the fall. Where possible, remove already affected leaves. Combine baking soda and horticultural oil (a safe product available from Garden Centers) and spray all leaves in the morning. Use 1 tablespoon baking soda + 2.5 tablespoons SunSpray horticultural oil in 1 gallon of water.
If these measures don't work, I suggest spraying with neem oil - always reading and following the label directions exactly.