How long for fungus gnats to die out?

[NorthernCosmos]

3-4 weeks ago I spotted fungus gnats in my tent. I immediately gave the buckets of soil a weak H2O2 soaking, and then placed sticky traps and vinegar/soap traps around in the tent. I also directed the circulation fan towards the top of the soil. This took out maybe a couple of hundred gnats in the first couple of days, as found on the traps. A little later I put the buckets in plastic bags so that the gnats have no free access to the drain holes and speed holes. I'm covering the top of the soil with pieces of pine bark.

Today, I'm still finding a few flyers in the bags when I take them off for watering. There were maybe 8-10 of them today in the bags from two buckets. Previously , when I had fungus gnats, I'd find larvae in the run off trays, but this time I have not seen a single larva.

My question is: How long will I have to keep the measures in place to be sure that there are no more live larvae in the soil? I'd guess for a period (how long?) after I no longer see any more flyers?

 

[Pat Puffer]

As long as the bags are on the pots, the gnats have a nice contained environment free of sticky traps. I had an infestation once and only hung fly strips and they were eradicated within a few weeks. I now have zero gnats.
Some plants get watered outdoors and i drag 1 or 2 in on occasion, but i am still gnat free. Another outbreak for me is always possible without sticky traps present. Cheap easy measure to have in place.

 

[Justin Goody]

Fungus gnats are little red/orange ones, yours are likely soil/root gnats.

Rather than risk burning roots with H2o2, use mosquito dunks/bits in your water or in your soil and it makes the environment impossible for them to thrive in. Sticky paper to get the others, and a sticky bug light get lots at night. Break their cycle once or twice and they will go away but they will always try to come back.

 

[Bush Doctor 77]

Get some BT and work it into the soil. I use shaved mosquito Dunks,

 

[013]

I’ve battled them off and on for a while, taken to bottom watering to keep top of soil dry, now I line bottom of pots with landscape cloth before adding dirt creates barrier, sulfur dust repels them on top side- they avoid landing in it. put ground up mosquito dunks and mosquito bits in top layers of soil, topdress with more mosquito bits and ground up mosquito dunks contains BTi bacillus thuringeinsis israelis which kills certain larvae

you can add mosquito dunks and bits to your water and let them soak overnight, stir with clean paint paddle bit then bottom water.

 

[Bush Doctor 77]

I’ve battled them off and on for a while, taken to bottom watering to keep top of soil dry, now I line bottom of pots with landscape cloth before adding dirt creates barrier, sulfur dust repels them on top side- they avoid landing in it. put ground up mosquito dunks and mosquito bits in top layers of soil, topdress with more mosquito bits and ground up mosquito dunks contains BTi bacillus thuringeinsis israelis which kills certain larvae

you can add mosquito dunks and bits to your water and let them soak overnight, stir with clean paint paddle bit then bottom water.

I bury about 1 teaspoon shaved Dunk about 1-2 inches deep whenever I plant/repot. Seven gallon pots I may add a bit more.

 

[NorthernCosmos]

Thank you everybody!

Good point about the bags keeping a closed livable environment for them. Even though the air volume between the pots and the bags is very tiny, I can see them being happy enough with that...

They may well be soil/root gnats, as 13goody13 suggests, since they are indeed black. I take it that the pest-factor and remedies are the same for the various gnats.

The mosquito dunks sounds nice, and I have had recommendations for those. They're not available locally, but I plan to add some (maybe the granulated version) to an upcoming zon order so that I'm prepared for the next attack.

The action plan now, will be to pull the bags off and let the traps do the work then - and not investing any more worry into it. Next round I'll have the dunks ready.

 

[skirk]

3-4 weeks ago I spotted fungus gnats in my tent. I immediately gave the buckets of soil a weak H2O2 soaking, and then placed sticky traps and vinegar/soap traps around in the tent. I also directed the circulation fan towards the top of the soil. This took out maybe a couple of hundred gnats in the first couple of days, as found on the traps. A little later I put the buckets in plastic bags so that the gnats have no free access to the drain holes and speed holes. I'm covering the top of the soil with pieces of pine bark.

Today, I'm still finding a few flyers in the bags when I take them off for watering. There were maybe 8-10 of them today in the bags from two buckets. Previously , when I had fungus gnats, I'd find larvae in the run off trays, but this time I have not seen a single larva.

My question is: How long will I have to keep the measures in place to be sure that there are no more live larvae in the soil? I'd guess for a period (how long?) after I no longer see any more flyers?

The adults have a 7-10 day lifespan, only harm, mating and egg laying. The damage causing larvae, feed for 2 weeks before they pupate. Eliminate the adults with insecticide/sticky traps and the larvae with BTI/Spinosad drench. I prefer prevention by not watering too often, letting my light, fluffy, airy medium dry between waterings, elevating pots, absolutely no standing water or saturated organic material and air circulation that keeps my foliage moving 24/7. Good luck.

 

[NorthernCosmos]

Thank you skirk!

What a neat grow space

I'm trying to determine if that picture is of something like three Pitts Specials?

 

[skirk]

Thank you skirk!

What a neat grow space

I'm trying to determine if that picture is of something like three Pitts Specials?

Thank you. That's the Eagle Aerobatic Team flying the Christensen Eagle at Oshkosh. It is designed by Frank Christensen, who after flying the Pitts, improved on the design when Curtis Pitts wouldn't sell him the company.

 

[NorthernCosmos]

Ah, Eagles - very cool!

Would love to go to Oshkosh - the US is a long way across a big ocean, but one day... I've been to the National Air Races in Reno though, as sort of a pilgrimage

 

[Plant Dad]

The adults have a 7-10 day lifespan, only harm, mating and egg laying. The damage causing larvae, feed for 2 weeks before they pupate. Eliminate the adults with insecticide/sticky traps and the larvae with BTI/Spinosad drench. I prefer prevention by not watering too often, letting my light, fluffy, airy medium dry between waterings, elevating pots, absolutely no standing water or saturated organic material and air circulation that keeps my foliage moving 24/7. Good luck.

love the grow room...

 

[NorthernCosmos]

Just got a bump on this thread, which reminds me I need to report that the gnats seems to have died out

The only things I used was the sticky traps and the soap/vinegar traps. The metric is gps (gnats per day - a new standard unit there ) in the soap/vinegar trap. It used to be maybe 10-15 gpd, but now it has had the same 3 gnats in it for a week or so, with no more of them wanting to take a bath... I see no flyers either and none crawling around in the trays.

It's such a relief to have won that battle!!!

 

[Plant Dad]

Glad to hear about Gnat problem is over. Lots of ways to get rid of the pesky things. Mosquito pucks, pine mulch and just Drying out pots before watering will get rid of them.

 

[Plant Dad]

how are those buds looking now?

 

[NorthernCosmos]

Skirk's or mine?

I don't think any plants got any real damage. The two Amnesia autos that grew up together with the gnats have been harvested with a normal yield of nice buds , and the later plants that were seedling when there still were gnats looks great

 

[Plant Dad]

Gnats are really just a nuisance unless plants are really young.

 

[Plant Dad]

Skirk's or mine?

I don't think any plants got any real damage. The two Amnesia autos that grew up together with the gnats have been harvested with a normal yield of nice buds , and the later plants that were seedling when there still were gnats looks great

Both...

 

[NorthernCosmos]

Gnats are really just a nuisance unless plants are really young.

Yes, the root aphids I had in my first few plants were a lot scarier! They came in with compost from my garden. I managed to limit and eventually exterminate them with tobacco & chili teas + a little H2O2. Since then I've been nuking the compost in a microwave oven to kill off pests.

I don't really know where the gnats came from though. Certainly not the compost as I haven't been using that for months since it's all frozen solid now. I hear some say that cheap store bought soil can contain gnats. Oh well, I'm just glad they're gone!

Both...

 

[GoogleGenie]

I really dislike the little b******s! I use steel wool to top dress to contain the adults. Works a treat in combination with something to kill the larvae like Tanlin.

I posted about it in this post