Not so invincible -- fungus gnats? Q's about cinnamon

[SarinahL]

Hi all,

So today when I peeked at my orchids for new signs of growth, I saw little white bugs on the medium of some of them.

They were white/translucent, 1-2 mm, moved like worms. I think they are fungus gnat larvae, but I haven't seen fliers around the plants (yet).

I thought using Brooke's 'best stuff ever' recipe, but for the life of me, I cannot acces cinnamon oil in my neck of the woods. I have looked EVERYWHERE and online, but alas. I'm not willing to go as far as ordering from USA (what with the shipping costs).

I do have cinnamon, vodka, or could use boiling water to make some of my own, as Ray's recipe said.
Has anybody made their own cinnamon extract and used it on their orchids yet?

Does it kill the eggs?
Do I need to change the medium? Because it was pretty new to begin with, and I found them in my phals so far, which are only slightly moist between waterings (never entirely dry, and I have minimal root rot so far so I stick to it). So I'm not sure if I should have fungi or decay already.

I read everywhere that fungus gnat are not harmful to orchids. Is this true?
Do they feed usually on fungi that are harmful?

thanks all!

[Ray]

I am surprised you cannot find cinnamon at a food store.

However, cinnamon is a fungicide, not an insecticide.

Here's the "scoop" on fungus gnats: The gnats, by themselves, are not harmful to orchids. The larvae, while they may primarily feed on molds and fungi growing on decomposing organic matter, will resort to eating roots if they devour all of the fungus.

So...killing the fungus could worsen the issue, not improve it.

The best things to to are as follows: drench the pots with a decent commercial insecticide. The next day, repot, cleaning off as much of the old medium as possible and replacing with fresh medium. About a week later, retreat with the insecticide, or eggs and larvae that remaining in/on the plant will reestablish the population.

[SarinahL]

No i have cinnamon, just not the extract or oil.

Anyway, what kind of pesticide should this be? I've never used any before. There's so many!
Why would I have gnats in relatively new (bark) mix...?

[Onleme]

We got Cinnamon Extract from a Naturopath. It was the only place we could find it here

Steve

[MelissaSE]

I use Bacillus thuringiensis (sp?) to keep fungus gnats under control. It may be available in garden centers in your location, Sarinahl.

I use the wettable powder, and just stir about 1/4 tsp. into a cup of water, then use it as a drench on the plants. It is very safe to use on plants you have in the house, as it doesn't affect anything except those little chewers. It is commonly used to control caterpillars and squash borers.

[Brooke]

Fungus gnat larvae are not translucent in color - they are a solid white and look like a grain of rice. In all my years of growing from seed I've never had any larvae migrate to the top of the container and expose themselves. I've also never found any larvae in bark, usually it is found in peat based mixes. Are you sure you have the correct larvae?

Brooke

[SarinahL]

Thanks all!

Brooke, I'm not 100% positive but they look like the pictures I get when googling "fungus gnat larvae". Also, I just got a bunch of new orchids, one of which was a psychopsis in very old looking medium. It might be this one carried it? It was my understanding that although your mix is fresh, it can still be contaminated from another? Trouble is, if there are no fungi in the fresh mix they're in, they'll start on the roots.

Also I saw one 'crawling' ( sort of like a caterpillar), so I shifted some bar and saw more ( maybe 3-4, seeing movement after staring at it for a while).

Either way I have declared war.

[tom499]

I would look to improve airflow over your plants, insecticides will help short term, but increasing airflow will stop them coming back.

[Brooke]

If your Psychopsis infested your other orchid you would see the adult gnats flying around the plants.

Google maggots and see if this looks like your worms. Whatever they are I hope you get rid of them.

Brooke

[SarinahL]

Nope, not maggots i do have jerkily flying black ones, also at the psych.

Airflow is indeed a problem in that particular part of the house, so I've already started looking for quick drying medium. I'm mounting the rest.