Fungus Gnats In Humboldt...

[Jay Tea]

Hi there. I've been a member for a while, just new to new posts! I recently moved down from the 36 and I'm doing light assist in a greenhouse. I'm having an issue with fungus gnats. Using Gnatrol, as of late, I'm interested in ANY advice. Does anyone aerate Gnatrol first? I'm thinking it can't hurt...

 

[LittleDabbie]

Welcome to the farm :D

 

[TSTEW313]

Just add the gnatrol to your water no need to bubble it an get you some yellow stickies the catch the mothers bug's an the gnatrol will kill the larvae in you soil

 

[Swell]

Welcome Jay Tea,

Here are a few more tips for reducing fungus gnats and their larvae:

-Ensure the medium dries adequately between waterings and avoid overwatering
-A light top dressing of Diatomaceous Earth will help repel them
-Top 1.5" of coarse inert medium such as perlite, hydroton, etc...
-Yellow sticky around base of plants (change half-way through cycle)
-Purchase soil from retailers that store it inside
-Reduce garbage leaf debris in the grow area

Look into a OG Biowar foliar pack.

Hope this helps a bit and stay safe on 36

 

[Seamaiden]

Welcome to the farm!

FGs are the bane of my existence, I find them everywhere, literally. I can go over to the sofa to smoke a joint, and I'll have one flying next to me before I know it. I haven't found good success with the usual methods, so I'm not a good person to ask about this. But, I have read an awful lot about using large numbers of nematode (gotta be fresh) to good result in problematic situations. Others have found relief by using mosquito netting wrapped all the way around the pots, so the adults don't have a way into the pots. I have observed that they simply don't establish themselves when pure perlite is the media as well.

 

[Jay Tea]

Welcome to the farm!

FGs are the bane of my existence, I find them everywhere, literally. I can go over to the sofa to smoke a joint, and I'll have one flying next to me before I know it. I haven't found good success with the usual methods, so I'm not a good person to ask about this. But, I have read an awful lot about using large numbers of nematode (gotta be fresh) to good result in problematic situations. Others have found relief by using mosquito netting wrapped all the way around the pots, so the adults don't have a way into the pots. I have observed that they simply don't establish themselves when pure perlite is the media as well.

Thank you, everyone who responded. Yeah, when I was inland more, I had spider mites, not bad, but they were present. Now that I'm more coastal, dealing with moisture, I was stoked at the idea of less mites...welcome to the land of Gnats! Oh well, thanks again!

 

[Swell]

I hear ya about the Fog vs Dry, and the perks/drawbacks of each climate. Closer to Tuna you get, the wetter everything becomes.

If there's an invasion of fungus gnats it can be tough to completely eliminate all of them, but have found it relatively easy to significantly reduce their populations. Spider mites on the other hand have proven to be more difficult to eradicate for me.

Just keep doing what your doing JT, and focus on killing the larvae with the BT drench. The fliers can be caught with heavy use of sticky traps. If you're in a greenhouse of good size you can use long rolls of yellow sticky trap.

Just curious, what soil are you using?

 

[3N1GM4]

I use fox farm ocean forrest mixed with coco and pearlite. I also have fungus gnats and can not get rid of them. I have treated multiple times with gnatrol, I let my soil dry untill the fan leaves just start to wilt so i cant let it dry anymore without stressing the plants. I have a 2+ inch thick layer of coarse perlite on top of the soil, sticky traps, they seem like they are gone and then come back with a vengance. When I tap or shake the plant the gnats fly out of the top of the plant, I thought they stayed in the dirt ate roots and then layed eggs in dirt and then died. I cant understand why they are roosting in my plant, are they eating it? I guess my next plan of action will be neem oil foliar spray?

 

[Michal]

The larvae are chewing roots below the surface, adults are more geared for procreation.

I prefer crushed Dunks top dressed myself, more of a slow and steady release of Bti.

 

[Sunbaked]

1/4 inch of sand on top of soil will kill the larva. works instantly and free. smothers larva and they can not crawl out

 

[3N1GM4]

I tried sand, I tried perlite, I tried everything. After using gnatrol 4 times and all of the sticky traps and spraying fan leaves with pyrethrin I only see one or two gnats every once in a while. I guess I am happy just having them under control. Those little buggers will find the one drop of moisture in your house and reproduce in it. If you dont get them under control then they will stress your plant into hermie

 

[Scorpius]

I tried my SCD-BioAG (probiotic) first, which is similar to what you are using (a bacterial insecticide). It does somewhat suppress them and if it were outside the local fungus gnat season (monsoons), it might have been enough. However, with a serious infestation, the only effective solutions I have found are predatory nematodes (from Ladies in Red) or Azatrol. The predatory nematodes are a bit messier to use and when I tend to need them, it is 100F+ outside and they could easily die during shipping.
Azatrol is an organic Neem extract and will suppress the worst infestations in a few days with one or two applications.
The downside is that Azatrol must be reapplied with upswings in the FG population. The nematodes will stay active in the soil for months. I am not 100% sure but think they feed on other organic material in the soil when there aren't enough insect larvae. I have actually washed them out of the soil after harvest and applied to new plantings for a second run of protection!

 

[3N1GM4]

Evergreengrowers.com has alot of beneficial bugs that kill mites and fgs

 

[Scorpius]

I tried sand, I tried perlite, I tried everything. After using gnatrol 4 times and all of the sticky traps and spraying fan leaves with pyrethrin I only see one or two gnats every once in a while. I guess I am happy just having them under control. Those little buggers will find the one drop of moisture in your house and reproduce in it. If you dont get them under control then they will stress your plant into hermie

Spraying fan leaves with pyrethrin is completely pointless in combating fungus gnats. They lay their eggs in the soil. The eggs hatch into larvae. The larvae eat the fungus that grows on the roots of the plant (hopefully the mycorrhizae you put in the soil or it could be infectious fungus). The larvae then molt into fungus gnats and spring from the soil. They fly around for awhile and mate before returning to the soil to lay eggs and die. The way they damage your plant is if the infestation is severe enough, they begin to damage the roots as they strip most of the fungus cultures from the roots. It can have the lesser effect of reducing your plant's uptake of nutrients by seriously damaging mycorrhizal cultures which aid in nutrient absorption.
A fungus gnat on the leaves is an incidental occurrence and the only effect you will have is killing an insignificant number of adult flies.
Azatrol, applied to the soil, is a fast, effective killer of fungus gnats. It attacks them on multiple counts. It prevents the larva from feeding and from entering the pupa stage. The dilute solution can kill adult fungus gnats on contact but more effectively prevents them from mating. Adult fungus gnats have the singular purpose of mating; they do not even eat.
You can also use predatory nematodes more effectively. They only attack the larva in the soil by predation but they have a latency of months, whereas the Azatrol has a latency of only 100 hours and must usually be applied at least twice to suppress a severe infestation. Azatrol is a lot cheaper and has a long shelf life.

 

[3N1GM4]

I use diatomateous earth and azamax and they just run right on top of both like it doesnt bother them.

 

[3N1GM4]

My latest try to combat them is to put my fox farm ocean forest in a pillow case and pour boiling water through it before I use it since they are already in the soil when you buy it.

 

[Scorpius]

My latest try to combat them is to put my fox farm ocean forest in a pillow case and pour boiling water through it before I use it since they are already in the soil when you buy it.

Yeah, my first FG infestation was courtesy of a bag of Roots from the local hydro store.
Ironically, I switched to MG Organic from Costco this year (cheap is good and you can always add to it) and had zero FGs until the spring rains brought them from outside. Depending on where you live, this may be an issue for you. Just b/c you sterilize the soil, doesn't mean you won't have to have an effective control strategy!

 

[3N1GM4]

I will never use MG soil again, not sure about the organic kind but the reg kind has little balls of liquit fertilizer that will nute burn your plants

 

[Scorpius]

I will never use MG soil again, not sure about the organic kind but the reg kind has little balls of liquit fertilizer that will nute burn your plants

Organic is a totally different animal and I have actually used MG Blue Bag successfully to grow cannabis when diluted a bit with coir!
MG Organic may not be Ocean forest but is still much cheaper even after you amend it! Would also make a good base for a "super soil". It already has some yucca and coir fiber in it but I mix it 3 parts to one part coir. You could also add guano, bone meal, crab meal, etc to bring it up to a standard more like Ocean Forest. Ocean forest can burn anyway - I have used it mixed 2pt to one pt coir with fantastic results, but it is still expensive!
I usually don't even go to that effort - just the 3:1 mix of MG Organic with coir, myco., bacteria, humic acid, azomite and feed with fish emulsion in veg and Big Bloom in flower. I have produced the best bud I have ever smoked (an Agent Orange cross - see image [you may have to dl and zoom...]) with this method. I have smoked a lot of bud over the last couple decades (1st time - Grasshopper, A"dam, 1996, Purple Haze, age 14, with dad) and have been an MMJ patient for 2 years.
KISS - Keep It Simple, Sherlock. And don't forget, organic rules, hydro drools (because of the harshness).
As a little FYI, the "little balls" in MG Blue Bag are actually silica gel, for water retention. You can't actually see the extended release nutes. You may be tempted to think it is like an "extended release pill" but the nutes are merely "extended release" by virtue of their molecular structure and how they react and release soluble nutes over time.
I might also add, I had a J27 female which lived for over a year and flowered three times, the last time producing seed so this rare breed could live on, crossed with another Cali rarity, Odyssey. She grew in a 5 gal bucket of MG Blue Bag and the only thing I ever did in a year is occasionally give her some Big Bloom in flower! I culled her after the seed run - the buds were getting strange anyway. She probably could've flowered a couple more times but you wouldn't like the buds she produced. After a year, the latest sets of fan leaves were still very dark green - indicating excess nitrogen. The MG BB was still fertilizing strong after a year.

 

[Scorpius]

The above plant produced the biggest calyxes I ever saw with that excess of N. They were as big as fully mature, seeded calyxes, even when empty!
Something that may be of interest to the other supernerds out there is that the seeds from her were somewhat on the small side even when completely 110% mature, like falling off the plant dry.
I guess, excess N= smaller seeds?
Might be relevant to hempseed producers because you want the biggest seeds possible!
As a side note, that year-old girl ended up looking like a gnarly old bonsai tree. I wish I had a picture, but for years, I have had a policy of not taking pictures because no pictures = no evidence for a search warrant. I have never sold and believe I have a legal right as an American to conduct my own silent protest against tyranny. In a time when full legalization is less than 18 months away in my state, I am starting to look at things a little differently. Earlier today, on another posting, I posted a picture of a cured bud I grew myself. This is the first time I have ever posted (or even photographed) any "evidence". At this point, I really don't care. I believe that the police in my particular locale (SW America, drug traffic central) wouldn't waste their time with me, especially when I have enough of a record for other, minor matters to show I won't go down without a fight. I have a legitimate medical need which far exceeds the needs of most, being a large person and having multiple degenerative orthopedic issues. At this point, all I am actually guilty of as an MMJ patient, is a state regulatory violation!
You see, in my state, MMJ patients are not allowed to cultivate. I am sure I can shove a metaphoric stick up their asses and make them beg for mercy, should they ever decide to take exception. I don't get traffic tickets anymore in my town because I fight them, successfully.