We farm from the MN river valley to 4 miles north.   Everything is sprayed except a few norther feilds.

The Valley should be named buckthorn ally.  Apparently Aphids overwinter on Buckthorn (so I told).  Generally southern winds blow in the summer, so yeah, were lucky when it comes to aphids.

This is our 4th years with them buggers, have sprayed 3 out of 4 years, with the first year doing 800 acres twice.   We left 90' for a test strip that year on the second trip and there was a 5 bushel decrease where we didn't spray.  That 90' strip was black come harvest, whish I had the digital camera back then.

Good luck, send some rain please!