Death to Fungus Gnats!

[2cb]

After 6 days, it's clear that the plants are goners. So much for this scientific experiment

Cannabis needs something like NIH/PUBMED, where cannabis scientists can post experiments on cannabis and gain reputation for their research ... It might be an interesting type database to browse.

http://www.ncbi.nlm.nih.gov/pubmed/23386598

 

[2cb]

Thanks for the comments. It's OK, as they are ready for harvest anyway, and the buds are not affected so much, so it's no real loss to me. This is just my entry for the scientific cannabis literature.

Abstract: Cannabis sativa in 3% Isopropyl Alcohol saturated medium ...

Conclusion: Despite killing all bugs, and without any signs of bugs repopulating the medium after 1 week, the plants showed definite signs of dehydration after 4-5 days, and definite signs of death at about 6 days. The leaves and stems seem to have been affected first and greatest, while the flowers seemed to be the least and last affected. Isopropyl Alcohol is a good means of killing gnat flies and other pests with soil saturation at a 3% concentration; however, it kills the plants also.

It may be studied in the future as a means of soil sterilization between indoor plantings as a means of eliminating indoor soil infestation (while clones/seedling are being prepared for example).

 

[2cb]

I should note that the dehydration was NOT due to over-watering, as the plants were drinking all the water from the same level of soil saturation with water-fertilizer solution every 2 days just previous to this experiment. And during the experiment, they didn't drink any noticable amount. Something about the alcohol just shut-down water absorbtion by the plants.

 

[Granger2]

Probably root damage. Bacillus Thurengiensis israelensis [Bti] works with no plant damage. Make sure it's fresh product. Add to watering/feedings till no more gnats. Good luck. -granger

 

[rhino420]

neem cake worked into the soil is all good ...seems like the alcohol would mess with microbeasties. making sure your medium is well cooked if using composts manures, or food scrap additives

 

[RB56]

Probably root damage. Bacillus Thurengiensis israelensis [Bti] works with no plant damage. Make sure it's fresh product. Add to watering/feedings till no more gnats. Good luck. -granger

It really is the way to go. I've eliminated FG from everything but my rooting cuttings in beer cups stage. It's not practical to make the soil/air interfaces impervious to pests at that small stage. Warm weather comes, fungus gnats appear. Gnatrol and everything is back on track. Fungus gnats will absolutely stop cuttings from rooting successfully.

 

[MensaBarbie]

Alcohol will kill your plants and any beneficial microlife in the medium so i saw that one coming. Pay the shipping and get some botanigard from amazon. Sprinkle on the medium when you transplant. Mix neem cake into medium before you transplant and dust the top of the media w diatomaceous earth after transplant. Prevention works best.

 

[MensaBarbie]

Picking all the leaves is counterproductive too btw. Just take off the dying older mature fan leaves from the bottom up. You need the upper leaves to draw nutrients up the plant. I take off all the leaves gradually over the flush week so all i have is sugar leaf at chop.
I just found out ISO can be used to zap mites when used 1 part iso 2 parts water in a spray. Evaporates after zapping mites without damaging plants. Not effective for medium pests like gnats tho.
ISO on roots is bad as you found out.

 

[Kcar]

Gnatrol works great if used properly.