I have been told to spray my apple trees early Spring with "non toxic...
It depends on what you are trying to control. For example, neem is listed as a spray for apple scab, but has not been proven to work. It is very important you figure out what the problem is and how serious it is before you spray anything. If you don’t, you are wasting time and money as well as potentially causing environmental damage.
Here is a link to help you diagnose and hopefully control your issue: http://www1.extension.umn.edu/garden/diagnose/plant/fruit/apple/index.html
Here is a link on growing apples in Minnesota with options for whatever issues you may be having: http://www1.extension.umn.edu/garden/yard-garden/fruit/apple-pest-management/
This article talks about various fungicides such as horticultural oils. Be aware that just because something is called “organic” does not mean it is not very toxic to wildlife, including humans. Sulfur is a commonly used example of something that can be fatal if misused: http://www.extension.purdue.edu/extmedia/bp/bp-69-w.pdf
I hope this helps rather than confuses you. Please feel free to reply if it is the latter!