it couldn't be a square, but a triangle because of where concrete and pond edge is.
Triangular (pyramid) protection works just as well; actually stands up better to strong winds, while shedding snow.
Getting rid of that pond would be a lot of work.
Spider mites miraculously appear in our warm dry homes during winter.
Misting daily can keep it down to a dull roar, but no guarantee.
Mist underneath the leaf in an upward direction.
In summer on the patio you can blast 'em hard with a hose/nozzle.
IMO, Mealy bug and scale are more unsightly and do more damage, tough to get rid of once you've got 'em.
Trick is to have a close-up look at plants especially in summer, as ants can bring scale (also aphids too for roses) because they've got a symbiotic relationship.
Ants "protect" the scale/aphids, etc., even removing them to their winter homes, and placing them back on your plants in spring.
Benefit = honeydew which ants love.
Half the battle is to get rid of all ants on your patio any way you can!
Boric acid powder is often used, mixed with a bit of honey, placed in a mayonnaise lid on ground where kids/pets can't get near it.
Ants take it back to their nest and whammo, the whole tribe is dead.
Despite hating chemicals, they're often necessary.
This year, before plants came in, John gave me some Dimethoate 480 (terribly stinky stuff, wear a mask when applying to soil in watering can).
Kent's right...fungus gnats are brutal.
I top-dress all my palms with an inch of sand because the top of sand dries quickly.
Results mediocre at best.
Moist soil seems to really attract fungus gnats, apparently their offspring feed on tender plant roots.
The trend in pesticides (these days) is no more small containers at the retail level.
Maybe mom+pop stores would still have smaller containers.
When I tried to get some Dimethoate 480 (before John's generous offer), heard they only have the large container size and it's $300.
When I buy a new plant, I always plan to quarantine it in case bugs are in the soil or on leaves.
But I usually forget.
Presto, bugs.
Barb