I have a spider mite problem, and rust. Can I mix my neem oil and copper solution into 1 sprayer, or do I have to apply separately?
If no info on the labels, contact the manufacturer.
Copper is most often used for control of algae or fungi and is a very toxic, to you, material. Then copper is most often used as a dormant spray or dust and spider mites are mostly a growing plant problem.
Neem Oil products alone are broad spectrum poisons that can also kill off any predators of spider mites. Understanding the life of a spider mite can help you with control without using very toxic poisons.
Here is a link that might be useful: About Spider Mites
I was using the copper to control leaf rust. I did not realize copper was so toxic. Does the toxicity carry over to the fruit like typical non-organic disease sprays, or does the toxicity dissipate in a reasonable time?
Copper is an acceptable organic fungicide, when used properly and with due care. However, mixing of any materials should never be done unless careful research says it is okay to do so. In some instances mixing two chemicals has resulted in one being rendered ineffective and in others a much more potent substance has been produced.
Is copper the right substance to control your leaf rust? What do the growing conditions contribute to that problem? Can a change in growing conditions solve the problem rather then some toxic chemical?
Here is a link that might be useful: About organic cides