With roses the recommendation for spider mites was to blast the underside of the leaves with water every three days for 9 days. This disrupts their cycle of reproduction. It worked. With your tree you may have to use a nozzle set on jet.

Neem is perfectly safe to use anywhere. Just don't apply in full sun in the heat of the day. Spider mites also like hot and dry conditions so just hosing down the crape periodically should go a long way in improving the situation. It's the dampness and humidity resulting from this spray that they dislike.

if you are thinking oil slick ... then you are thinking about doing it improperly ... with a pump tank.. and a little practice on the driveway with plain water .. you should be able to set the nozzle and tank pressure .. and along with the handle trigger.. learn how to apply product from out the tip of the wand ... with little or no drift at all ... [the driveway because you can see the effect of what comes out the tip ... and it should dry very fast on a sunny day ....]

if you can create larger drop of product ... gravity dictate it falls to the ground .. rather than creating a mist.. which can drift on a slight breeze .. ... gooo gravity ... lol ...

but as noted.. just a repeated stiff spraying with water.. will probably do the trick ... its not really about total mass destruction.. its more about reducing the marauding hordes to tolerable numbers ... try it with water .. before you raise the process to defcon4 .. lol... the hort oil ...

ken

Thanks everybody! I am going to try hosing it down a few times first before resorting to neem oil.