Hort oil is nothing new...whether you use a petrol based oil or a veggie/seed based oil, they both do the same thing. The pre-packaged hort oil contains an emulsifier, where previously a little soap was added.
Although it provides SOME ovicidal benefit...you absolutely cannot spray and go about your business...you still need to spray every few days depending on temp, # of different groups of life stages you have (could have eggs hatching daily or every 5 days)
I would not want to spray petroleum on my buds...so in flower use another oil! Safflower is probably the lightest...I use organic hemp oil when necessary.
As for what kills eggs (and all other stages of insect life including soil-borne larvae)...bag up plants, suck air out with vacuum, fill up like balloons with CO2...tie up for 24 hours...all bugs dead.
clear bags are available...do not fill too fast as the gas is cold and can frost damage! (filling two large bags at once I damaged the second bag a bit, but WAY better than the mites) This can be done with all stages from seedlings to cut harvested bud. One time shot.
...no residual poison.
This will not be the case for long!
Oh...and welcome [Artemus] ClydeFrog...to the wild wild west!
Copying & pasting from
http://edis.ifas.ufl.edu/cg002 run by the University of FL. This was linked by a site run by the FL Dept of Agriculture & Univ of S FL Horticulture Dept.
http://entomology.ifas.ufl.edu/creatures/
Anyway, here's the quote........ Need for controlling spider mites is based on temperature and humidity conditions, spider mite population levels, tree vigor, and time of the year. Petroleum oil provides some ovicidal activity against spider mite eggs. None of the other miticides provide ovicidal activity, and their residual activity must be sufficiently long-lasting to kill subsequently emerging larvae.
I don't think the other Hort Oils have the same ovicidal effect. If they did, I would think the site would have mentioned it.
Bonide makes one called All Seasons and they're an old & respected company. So I'm sure if there were any side effects they wouldn't be making it.
I used it myself and it made my leaves softer, almost like I put moisturizer on it.
If I was in flower, I'd use Mite Destroyers or Predatory Mites on Spider Mites depending on how close I was to harvest (predatory mites take time to colonize).
That said, I have white mites. Very little research has been done on them. Broad Mites are a pain but Cyclamen Mites are worse. Every thing I read on them says to just throw the plant away. I'm not sure which I have because they look the same. They have different looking eggs, but I haven't been able to find any to look at under a microscope.
Anyway, point is the lady bugs and various hort oils I've been using has kept them off the plants for the most part (lady bugs rule) and have been keeping them on the edge of extinction. So if worse comes to worse, I'll keep the lady bugs & hort oils going till harvest.
But I'm going to make one last ditch effort to kill them off. The Colorado State Univ suggested these predatory mites since they have been proven to feed on a wide variety of mites...... Metaseiulus occidentalis, Mesoseiulus longpipes, Neoseiulus barkeri, Neoseiulus Californicus, Neoseiulus fallacis, and Phytoseiulus persimilis.
Nothing has ever been proven to kill white mites but this is probably my best shot.
As far as the Spider Mites, early on I caught Spider Mites, White Mites, & Fungus Gnats all at the same time. I sprayed with Mite X (another hort oil) and released 3,000 lady bugs and that's the last I saw of the Spider Mites or Fungus Gnats. That's why I said that Lady Bugs rule. I just wish they'd finish off their food supply, if they did I'm sure the White Mites would be gone too. I hope the predatory mites I choose are as effective.