Hope someone can give me some advice..(@Hieronymous ?)

I've recently had these little bugs (FruitFly's maybe?) starting to populate a little more than I would like in my greenhouse...

I've tied wiping citronella oil on the walls of the greenhouse and under the propagation trays, and this makes the bugs go a little crazy, but they don't vacate...

I've now put these yellow strips all around the greenhouse.
Over the last few days they have been catching the bugs.. but doesn't seem to put a dent in their population..

What is the next best option?
Will spraying Baygon on the wall surfaces kill the plants at all?
Should I go buy one of those electric zappers?

first i would try this, put in some cups with
some dishwasher soap,
some lemonade and
a dash of vinegar

The flies will investigate it and then drown because the lack of service tension.

If this doesn't work its better to spray DDT everywhere

i find this a good solution to all of lifes troubles

"The use of DDT in Australia has been fully banned since 1987"

I'll try the soap/lemonade/vinegar...

...failing that, the 3rdI method!

If that are fungus gnats I would recommend getting a pinguicula.
They are incredibly efficient at kililing fungus gnats.
...my favorite mass murderer.

WOW that's a great plant
Below the trap after a day or two .

I don't know what the ID of those bugs are, but in case they have a lifecycle of eggs and larve in the ground, you can purchsae some diatomaceous earth at a greenhouse, or cheaper at a pool supply place. Sprinkle a good layer on the top of the soil, and as the larve try to climb out of the soil, the microscopic sea shells that is diatomaceous earth will cut them to bits, ending the infestiation by stopping the life cycle.

* Soap/lemonade/vinegar stuff.....check!
* Fly-paper.....check!
* Diatomaceous Earth.....check!

Haven't been able get a grown pinguicula ('Butterwort' ) anywhere....

I'm trying to see if I can get a grown Drosera ('Sundew' ) maybe, they also look beautiful!

that pinguicula is awesome!

Just ordered some seeds

Regarding gnats, ime once there is an established population the only thing you can do is let the media and area get real dry, but not sure if your set up will allow that.

Maybe get a dehumidifier? Whats the humidity at?

How is the air circulation? Gnat populations can be taken down with some fans ime.

Hey adam - you can checkout this other thread which shows pics of how I have the fan setup. Circulation is pretty good, I can see most of them swaying in gentle breeze

The humidity is not too high, though i have been keeping the soil well watered every few days. I left them without water for almost a week before putting them outside in the rain overnight and then covering with the diatomaceous earth. There was quite a few larvae I found underneath the bottom when I took them out to water.

I'm a little concerned about leaving the soil to dry too much, does anyone have experience with acacia's in these size grow tubes? How old do they need to be before you can let it get drying and rhizobium bacteria to get a better hold?

I think I'll just order some seeds and grow a couple of pinguicula's and sundew's anyway - they look like great ones to have around as a permanent, natural solution... and much more fun to observe

Looks like fungus gnats to me too.

It's the curse of indoor growers everywhere. For a grow that is a single season crop then I'd look for organic solution but for a long lived tree that can only accumulate trivial amounts of toxins in it's juvenile stage, I'd just use an ordinary insect spray - Mortien, black and gold - whatever.

Just spray the room and don't directly spray the plants, spray it close to them but don't paint the leaves with it. Repeat at least twice in the next few weeks to get the larvae when it hatches.

I do mine in a tote or bucket, I use it like a fumigation chamber and never spray directly onto the plant. After spraying I put a board over the top of the tote/bucket and let it sit for about 30 mins. Not much will survive such a fumigation except the larvae - hance the need to re-treat in a week or so.

Get all the plants out of the room and spray it with poison of choice, fumigate the hell out of it and shut the door for a few hours and wait it out.

From my observations fungus gnats have two main sources for infestation. The first one is potted house plants and the other vector is introduced through fruit and vegetables that we bring home, onions being the main culprit. The bastards live in the loose layers of onion's skins. So put them in a gnat proof setup, my onions go into a stocking and I always find heaps of dead gnats in that stocking.

I see you are using Rockwool - an excellent choice. If it's pre treated properly it can be the possibly the best medium there is for many plants (not all). Many or possibly even most people don't know how to pre treat rockwool and never have optimum results when using it for a growing medium.

---

How to pre treat rockwool
I'm very surprised how many commercial growers don't understand this, a simple ion sample should be indicative enough for any commercial hydroponic producer to understand this but many growers ignore this basic information we determined in the early years Rockwool culture. Dutch growers had it refined within 3 years after the introduction of Rockwool, but the rest of the world has struggled to understand this fundamental principal of Rockwool culture.

Rockwool (untreated) has a property where it buffers the initial pre soak PH 1 full point higher than the first soak. I believe some of the grodan brand is pre-treated but most brands are not.

So if I have plant that uptakes nutrients optimally at PH 6 the Rockwool has to pre-soaked at PH 5. After the the pre-soak the Rockwool will typically settle at 1 full PH point higher than the pre-soak, so a PH 5 pre soak will result in a working PH of PH 6.

Many people will do the first wetting at system PH (PH 6) with the normal nutrient solution, which the Rockwool will buffer 1 point higher (PH 7) and the system will always hover around that mark forever (far from optimal). Pre treat your Rockwool and you will never look back. the plants will be able to utilise (almost) all the nutrients they come into contact with and thrive like never before.

Nice plants Shadow!

regarding the pinguicula.

They like to stay on the wet side so don't let them dry out. (although they do seem to bounce back easy if abused)
A self watering pot can be a good idea but not necessary.
The one in the green pot (above) is filled with water and let stand for ten minutes once
a week and I also have another which sits in a constantly moist environment and both are thriving.
When your plant gets to a good size it's super easy to take cuttings.
The new leaves that spring out from the sides grows roots so just stick your fingers
in there and pull out a new little plant.

I have about 30 houseplants in 25 square meters and when I got that one plant it completely shredded my gnat infestation.

Also, for most meat-eaters (as far as i know) a soil with little to no nutrition is preferred as
they get their nutrition from the animals they eat.
I'm not really sure about the pinguicula though as mine is sitting in the earth it came with and the other is
growing on a plastic hygrolon mat.

Thanks for your insights guys!

You're right. They are fungus gnats. I pulled out a microscope today and studied one. Looks exactly like this:


I've just done another baygon spray. That should decimate them for a while, but considering this is going to be an ongoing hobby for me, the carnivorous plants sound like it's gonna fix for good.

Hieronymous, what I'm using for the soil was a sterilized batch from a nursery that they use to grow a.suaveolens, in those particular propagation tubes. The white layer on top is about 5 ml of diatomaceous earth that has soaked up a bit of moisture from the previous soak i have them.

I'm about to do a new batch of seeds, so I will try some rockwool, keeping in mind the +1Ph factor you've highlighted.

imPsimon, thanks again for the tips on getting the best out of your favourite 'mass murderer'. They sound like a pretty cool idea to keep at places like outdoor restaurants to keep insects away. I have months of impatient anticipation ahead of me until I have any 'sundews' or 'butterworts' mature enough to take over the job.

Try spraying beer on the plants...
If the bugs are drunk they are easier to handle!