ive got Symphilids , ive been spraying every 3-5 days with a neem oil/liquid soap mix. it seems to be working , on the surface.
but what about down in the roots?

im growing in clay pebbles , my table is 800cm's by 180 cms x 15 cms and its a bed of 200 ltrs of pebbles.

now , if Symphilids live in the roots , should i drench the pebbles and roots in my neem oil mix?

the Symphilids dont seem to have taken a huge hold on the plants and i only ever see one at a time crawling over the leaves , a good spray of oil and i dont see another for at least 5 days.

im just concerned about whats going on down below the surface.