Treating pests in terrariums with CO2

[Froggle]

I've read the sticky & have tried Marty's idea of treating pests on my plants with CO2 using the dry ice method. I have a couple more questions so thought I'd post them here (wasn't sure if I should post here or on the end of the sticky so I've done both)

When I used this method the other day I did as follows:
1. I took the plants out of my tank & placed them in a plastic esky (I could not treat them inside the tank as my tank is a paludarium & I would have killed the fish living in the water at the bottom.
2. I got small pieces of dry ice, placed them in a couple of plastic cups & added warm water.
3. I placed the cups in the bottom of the esky & let the gas fill it then put the lid down (leaving it 'ajar' - about 5mm open).
4. I left the esky like that overnight.
* I would have preferred not to leave the dry ice in the esky overnight due to the temp drop but when I tried letting the gas spill into the esky from cups at the top, the gas seemed to clear too quickly & I wasn't sure that all the air had been displaced - I'm not sure if CO2 becomes transparent when it warms to a certain temp?

In the morning there were certainly alot of dead aphids on the plants & I couldn't see any live ones, so I think it worked!

My question to you guys is:
1. does anyone know if CO2 becomes transparent once it warms - therefore invisible to the eye?
2. has anyone else tried this method?
3. has anyone else tried this method using baking soda + vinegar or yeast + sugar to create the CO2. If so can you guide me on how much of each to use to to treat plants in say a 100 litre container? These methods would have the added bonus of not dropping the temperature which is better for tropical plants including my orchids!

Thanks in advance!

[Ray]

CO2 IS "transparent" (colorless) at all times. The "fog" you see is frozen water vapor from the air.

CO2 is significantly more dense than air, so will fill the container from the bottom up. You'd really be better drilling a small hole in the container top, and letting the carbon dioxide "push" the air out though that alone.

Go with a larger container, and put the cups with dry ice apart from the plants, and you'll have no chilling issue, as the gas warms pretty quickly. The yeast idea won't generate CO2 quickly enough to work well, and vinegar is a herbicide, so I don't know that I'd want to risk my plants near it.

I will add that many part of pests' life cycles take place in the substrate, so while you may have effectively killed bugs on the plant, some might be in the tank still.

[Froggle]

Many thanks for the reply & the info Ray!

I had to pull the tank apart to get the plants out anyway (because of the way it was set up) so I've replaced all the substrate with new boiled sphagnum. I'm hoping the boiling is enough to kill any nasties dormant in it. All the orchids kept in there are mounted so they got CO2 treated on their mounts.

I appreciate the info re yeast & vinegar - I guess I'll stick to using dry ice - it's a bit of a drive, but not that hard to get hold of here.

Do you think that pests in all their life cycle stages would be killed by the CO2 treatment (providing the substrate is treated also) ?

Again many thanks!
Laura

[Ray]

I can only guess that eggs, pupae and larvae need oxygen, so I suspect they would also be killed by the treatment, but I have no idea what length of time of treatment that would require.

I'm quite sure boiled sphagnum is cleaned of them.

[Paul]

I have found the C02 method to be useless with snails.

[Froggle]

Thanks again Ray. Paul how do you tackle snails? So far I've only had aquatic ones & i keep their numbers down using a snail trap. Laura