my ficus and juniper have never been effected despite my entire backyard being a magnet for them. But i have seen others get mites on juniper. I'm trying a product that seems to good to be true but has amazing reviews and is used by some real live bonsai artists on here. It's called pro-tekt by dyna gro. it's technically a fertilier but it adds low levels of silica to the tree and toughens the leaves making them unappealing to sucking insects. Haven't tried it yet but I get it next week. It seems a lot more promising than a constant chemical assault on those microscopic dudes that will always be around anyway
Silica based nutrients, if they work at all (various properties have been granted to silicium applications but only a few of them were proven to be correct), mainly stop insects with teeth. Plants make trichomes to protect themselves from munching insects, these either act as shards in the intestines, or wear down the teeth of snails for instance (yes, they have teeth, don't google them). Sucking insects probe right into the sap stream, into the veins so to speak, and they know how to find them. Layers of trichomes can keep them at physical distance, but only until they find a weak spot.
Wherever the wind blows, silicium follows, since sand is made out of the stuff. Especially in our inorganic soils, there's a lot of silicium already present (lava rock, perlite, most clays). Adding more wouldn't do a whole lot.
I know a few companies that sell silicates (Sodium silicate or potassium silicate) to combat mildew. After trying a few of those products, I can't say I saw them being effective.
Spider mites do great in arid environments, just like plants that love silicium, and these arid places tend to be high in silicium by default. So if spider mites have evolved in areas high in silicium, would it be logical for them to be affected?
Do as you please of course, I just have a history with the stuff and I can't really find any logical arguments to use it again ;-)
Just one thing: if the silicium product is sodium silicate based, use extreme caution because it might just kill all foliage like it did on some of my grapes. Apply it in the evening or later afternoon only, and be prepared to hose it off if you get some salt stress signals like brown spots and dead plants.
I know that some very big companies use predatory mites in indoor settings where they want to protect workers from chemicals. Like Neoseiulus Californicus. The companies providing these predators are growing in Europe, but I believe there might be an emerging market on the other side of the ocean as well. It might be worth checking it out. Over here, we're moving past that stage onto "predatory" fungi and host-specific intestine/embryo disrupting bacteria as well as nematodes. Too bad these companies are all very, very intertwined with larger groups like Monsanto/Bayer and they're patenting those things by the shipload, making them virtually inaccessible for consumers.
