Fungicides act somewhat differently than do Insecticides, targeting different species of living things, although some fungicides will kill beneficial insects when used improperly. Any product that is meant to kill something should be used with great care.
Plants that need constant applications of pesticides are not a good health.

Kim, what do you suggest as a over the counter fungicide?

What do you need to control?

I have scale..

Scales are best controlled by applications of dormant or superior oils, or sometimes if done early enough in the scales life an Insecticidal Soap.

Zyperiris, you're confused about fungal diseases and insects. Insecticides are what we term those products used to kill insects. Scale is an insect, of which there are many hundreds of species in North America alone. We combat scale insects as Kimmsr mentioned above.

Fungicides are chemicals that act against fungus diseases, not insects. Fungicides should only be used when a disease outbreak is serious enough to warrant it. For most of us, prevention of disease is the best policy.

Always be certain to have a pest problem identified properly before you decide to apply anything or take any action. We'll be glad to help, if we can.

Rhizo, thanks. I think I will be using dormant spray this year..in the dormant season...

What fungicide should I use for powdery mildew on my roses? Last year the systemic stuff worked great. This year the rose is a mess. All the new leaves are covered with it -- there is plenty of air circulation and it hasn't been wet here in 2 weeks (mid-Washington state). Commercial or home-made fungicide recommendations welcome. I have to act fast. Even the flower buds look malformed...

rvermar, GreenCure works on powdery mildew, and is organic.

Deanna

Powdery Mildew is easily controlled, when necessary, with applications of either a mixture of 1 teaspoon of baking soda mixed in 1 quart of water, or a 50/50 mixture of fat free milk and water, sprayed every 7 to 10 days as a preventive or sprayed every 5 to 7 days if the plant has PM.
The same mixtures would be effective at controlling Black Spot.