Yeah, DE might be your best, and least side-effective (is that a word?) treatment for the short term... but it will also damage
bees and
ants, so best not to use if you have active pollination going on.
Since it's not a scale insect, but soft bodied like an aphid, I wonder if an aphid treatment might have some effect? I use a rosemary and peppermint oil in a mild
soap spray. For really bad clusters I'll add some ethanol... but that can sometime damage foliage with open pores- like a nasturtium.
"A healthy population of beneficial insects is the single most effective way to control sharpshooters. One of the most effective is a small wasp that feeds on the pest’s egg masses. Praying mantis, assassin bugs and lacewings are also extremely beneficial at managing glassy winged sharpshooters.
"Avoid chemicals as long as possible because pesticides can decimate populations of beneficial insects, which means sharpshooters and other pests are free to multiply like crazy. Additionally, pesticides haven’t been proven to be very effective when it comes to controlling spread of bacteria, and in time, pests can build up immunity and control becomes much more difficult."
Read more at
Gardening Know How: What Is A Glassy Winged Sharpshooter: Learn About Sharpshooter Damage And Control
https://www.gardeningknowhow.com/plant-problems/pests/insects/glassy-winged-sharpshooter-control.htm