I had recently seen something that described spraying rose bushes with water
to get rid of spider mites, so I image-googled for "spider mite web."

Yes, that's it exactly! The webbing looks exactly like the web in
that picture. The docs on Spider Mites seems to say they concentrate
on the undersides of leaves, but I find them all over the leaves which
is probably because my leaves are sheltered from the rain. So I've
been hosing the leaves from a distance for about 5 days, since the
lifecycle is 4-10 days I should hopefully damage the population with
this water. They seem to be very, very vulnerable to water. I
thought aphids were bad, but these mites seem even worse.

Thanks

Steve

http://hortipm.tamu.edu/pestprofiles...brcycmit.html.