A few weeks ago I noticed some very tiny bugs among one of my U. warburgii. Armed with a loupe & Google, it appears that they were the smallest aphids I've ever seen. Since I've heard that utrics are like dews in their sensitivity to pesticides, I planned on my 1st use of the relatively new (at least to me) uber-pesticide, fungicide, wonder-cure-all --> Neem oil. However, somewhere in my head a distant brain cell was struggling to recall more details regarding someone, somewhere in CP land using CO2 (carbon dioxide in the form of dry ice) to eliminate pests. I did some searches in the forums & found nothing. Back to Google & found this post over on the orchid forum. After endlessly searching for a CO2 supplier, I finally found one that was open past noon on a Saturday.
Bottom line, I mostly followed the instructions from the orchid forums* --> the aphids bit the dust** & the plants had a boost in growth.***
I'm interested to hear if anyone else has used this method, & if so, how things worked out - especially with other pests, like mealy bugs or thrips. Although it seems that this should work for any oxygen-breathing pest, some pests (specifically mites) appear to be unaffected.
Given the relative ease of application, low cost, lack of carcinogenic/mutagenic chemicals and possible side-benefit of enhanced growth - - - why isn't this approach more popular?
* - after starting with his methodology, I evolved to using something similar to his 'top-off' method. Basically, I placed CO2 in a double-wall, large plastic cup and then poured 1/8 cup of near-boiling water on the cubes of CO2. I then allowed the resulting vapor to pour down into the tank. Then repeat multiple times. Wait for an hour or 2 & repeat again... The hot water (as stated in the link), helps to reduce the impact from the temperature drop caused by dry ice. Just using dry ice might work but it might also freeze some plants (& kill them).
** - while I never noticed more than 3 or 4 of these tiny aphids at any 1 time - after the procedure, I sprayed the warburgii foliage with RO water and hundreds of tiny corpses formed a 'bathtub-ring' around the outer edges of the pot. Like roaches, there are always many more than you see.
*** - Some plants appeared to have a dramatic jump in growth, while others were unaffected. I'm planning to play around and 'pour' some CO2 into the tanks when the lights are on (when the plants can actually use the stuff) and see how they do... Maybe the boost was in my imagination ...