what do fungus knats do? can we live with them

[keepleft]

thanks frazzle. im going to try the guardian when i finish this bottle of microbial. its ALOT cheaper too

[power]

I used Mavric twice. Once every seven days and the flies are gone. Dillute 10ml to a litre of water and pour it on..

 

 

Best of luck

 

N

[keepleft]

thanks power you have saved me the effort of asking this question! you must have read my mind cause im sick of those little flies!

 

ive used microbial as a drench for last 3 crops (with mortein house and garden). it seemed to be working as the flies decreased in number but then last night i lifted the plastic over the rockwool and the bitches were there in numbers! im giving up on that stuff.

 

i have a question about mavrick which i need to clarify before i use it (your using it in soil so may be a bit different). i am using rockwool in a recirculating system. if i add the mavrick at a ration of 10ml per litre as a drench, should i then just let it run back into the reservoir (which is 200lts) or should i dump and add new water/nutes? im a bit concerned of doing any damage to the ladies!

 

maybe wantdachronic will know the answer cause i remember you mentioned mavrick a while back for this purpose.

 

thanks

[Luke Skywalker]

If all other entry points have been covered the gnats must be coming in either with the plants themselves, or when you enter the room. I would say recheck and double check all the possible entry points, including edges of walls for possible entry points.

 

I would dump rather than recirculate any pesticide unless you know it's not systemic and can't hurt your plants....

 

I'd have to say that pythoff and DM guardian are the same thing, but the pythoff seems a little less... how do I put it.... wanky? But that's just me, as I don't like Dutch Master very much....

 

Monochloramine won't "cure" fungus gnats afaik, but it will make life hard for them. Try putting some sticky fly traps like the aeroxon type around the room and stretched across the pots, it won't kill the whole population but it will certainly help.

 

I would always advise growers to be hesitant to use harsh chemical pesticides on their plants, these are usually (though not always) systemic in nature and are not designed for MJ which isn't just consumed, it's burnt, which can totally change the nature of the insecticide and quite possibly harm you or those who consume it.

 

The key with using any treatment is repeating, usually after 6 -7 day period. This ensures that future generations of insects are wiped out. Best practice is doing treatments three times, 7 days apart IMO.

 

Ideally I'd say go with the Integrated Pest Management route like Pa-uul has suggested. Entomopathic nematodes are usually what's prescribed for fungus gnats, although the mites, (perhaps phytoselius persimilis was the one?) are another option, I'd say less effective though. Ideally isn't always practical or cheap though.

 

Hope that helps.

 

p.s. you could also give Dipel a go as a drench, a person I greatly respect has told me that this product normally used for caterpillars has worked well for fungus gnats too. There is a variety of Bacillus thuringiensis (the active ingredient in dipel) which is specified for fungus gnats, ( subspecies Israelensis, trade name Gnatrol) but he didn't know about that, and had just used the plain old bacillus thuriengiensis ssp. kurstaki, i.e. Dipel. May be worth a shot, as this is totally and unequivocally harmless to plants and people, as well as just about everything else except caterpillars, (and hopefully fungus gnat larvae.... ) It is used for control of mosquito larvae in waterways, so I can certainly imagine it would have similar effects on gnat larvae.

 

If you can find gnatrol though you'd probably have better results, but I'm not sure if that's the name they sell it in australia as, or if it's even available here.

 

Hope that helps, and good luck.

[keepleft]

hey luke i know gnatrol is available in the UK. i looked for it a while ago and its not available in australia (not by that name anyway).

 

found this infor on Bacillus thuringiensis, interesting (and it confirms your spot on on the type of BT used to control knats - which is different to dipel, but by your suggestion dipel will be ok)

 

BACILLUS THURINGIENSIS

Bacillus thuringiensis, commonly sold as B.t., is a bacteria from which a toxin is manufactured that has insecticidal properties against vareious insects. Compounds sold as B.t. contain the manufactured toxin and not the bacteria. Several strains of the bacteria produce toxins specific to different insects. The products are specific to individual insects and are not toxic to other pests or animals.

B.t. kurstaki commonly sold as DIPEL, THURICIDE, or BIO-TROL can be used to control the leaf-eating caterpillars of various butterflies and moths. Caterpillars commonly controlled with B.t. kurstaki include tent caterpillars, gypsy moths, peach tree borers, webworms, and codling moth.

 

B.t. israelensis is used for effective against the larval form of some members of the fly family (Diptera) including black fly, fungus gnat and mosquito. House flies, stable flies and blow flies are not controlled.

 

B.t. san diego has activity against leaf feeding beetle larvae such as Colorado potato beetles and the adults and larval stage of elm leaf and willow leaf beetles.

 

Make sure to read and follow all labeled directions.

[keepleft]

hey luke found some more info on BT

 

"Table 1. Commercially Available Biological Pesticides and Natural Enemies for

Controlling Fungus Gnat Larvae.

 

Biological: Bacillus thuringiensis subspecies israelensis (Bti) (Gnatrol)

 

Comments: A naturally occurring, spore-forming bacterium produced commercially by fermentation. Bti applied at labeled rates provides temporary control and is toxic only to fly larvae, such as mosquitoes, black flies, and fungus gnats. Repeat applications commonly are needed for long-term control. This Bt is a different subspecies from that applied to foliage to control caterpillars. Bt labeled for caterpillars is not effective against fly larvae."

 

based on this does that mean that DIPEL not effective on fly larvae?

 

there is also further info on insecticides

 

"Insecticides Insect growth regulators (e.g., azadirachtin, kinoprene, diflubenzuron,

cyromazine) applied to container media can be the most effective insecticides

for controlling larvae. Drenching media with an organophosphate (acephate, malathion) or carbamate (carbaryl) also kills larvae, but this can be hazardous and will kill many different organisms, including beneficial species."

 

does anyone know what the active insecticide of MAVRIK is?

[keepleft]

a great read on these pests!

 

http://www.ardentermite.com/2003/pestnotes/pnfungusgnats.pdf

[keepleft]

useful info on active ingredients in pesticides - mavrik is FLUVALINATE

 

APPENDIX 1: Active Ingredients in Pesticide Products Used by Counties - Outdoors

 

2,4-D (and salts)

4-Aminopyridine (Avitrol)

Acephate (Orthene)

Acetic Acid

Allethrin (d/l-trans-allethrin)

Aluminum Tris (Aluminum tristearate)

Amitrole

Anilazine (Dyrene)

Baygon (Propoxur)

Bendiocarb (Ficam)

Benfluralin (Balan)

Bensulide

Boric Acid (Orthoboric Acid)

Brodifacoum (Talon)

Bromacil

Bromadiolone (Maki)

Captan

Carbaryl (Sevin)

Chloroneb

Chlorothalonil (Daconil)

Chlorpyrifos (Dursban)

Copper Sulfate

Cyfluthrin

Cypermethrin (Barricade)

Dacthal (DCPA)

Diazinon

Dicamba (Banvel)

Dicarboximides

Dichlobenil

Dichlorvos (DDVP)

Diphacinone

Disulfoton

Dithianone

Dithiopyr

Diuron (Karmex)

DSMA (Disodium monomethanearsonate)

Ethion

Ethylene Glycol

Ethylene Oxide

Etridiazole

Fenarimol (Rubigan)

Fenbutatin-oxide

Fenoxaprop-ethyl

Fosamine ammonium

Fosetyl-aluminum

Glufosinate-ammonium

Glyphosate

Hexazinone

Imidacloprid

Insecticidal soaps

Iprodione (Promidione)

Isobutane

Isofenphos (Oftanol)

Isovaleral (Calcium salt)

Malathion

Mancozeb

MCPA (2-methyl-4-chlorophenoxyacetic acid)

Mecoprop (MCPP, CMPP)

Mefluidide (Embark)

Metalaxyl

MSMA (Monosodium methanearsonate)

Methoprene

Metsulfuron-methyl

Oils - Horticultural, Mineral

Oryzalin (Surflan)

Oxadiazon (Ronstar)

Oxyfluorfen

Oxythioquinox (Morestan)

Paraquat

Pendimethalin

Pentachloronitrobenzene (PCNB)

Phenothrin

Phenyl Methylcarbamate

Piperonyl Butoxide (PBO, a synergist)

Prometon (Pramitol)

Propamocarb Hydrochloride

Propiconazole

Pyrethrins

Quaternary Ammonium Compounds (Barquat, Bio-quat)

Resmethrin

Siduron (Tupersan)

Sulfometuron-methyl

Tetramethrin

Thiophanate-methyl

Triadimefon (Bayleton)

Trichlorfon (Dylox)

Triclopyr (Garlon)

Trifluralin

Triforine

Vinclozolin

Zinc Phosphide

 

 

APPENDIX 2: Active Ingredients in Pesticide Products Used by Counties - Indoors

 

Acephate (Orthene)

Allethrin (d/l-trans-allethrin)

Avermectin (Abamectin)

Baygon (Propoxur)

Bendiocarb (Ficam)

Bifenthrin

Boric Acid (Orthoboric Acid)

Brodifacoum (Talon)

Bromadiolone (Maki)

Calcium Silicate

Chlorpyrifos (Dursban)

Cholecalciferol

Cyfluthrin

Cypermethrin (Barricade)

Diatomaceous Earth (Infusoral Earth)

Diazinon

Dicarboximides

Dicofol (Kelthane)

Diphacinone

D-Phenothrin

Endosulfan (Thiodan)

Esfenvalerate

Fenoxycarb

Fenvalerate

Ferbam (Carbamate)

Fluvalinate (Mavrik)

Glutaraldehyde

Glyphosate

Hydramethylnon

Hydroprene

Malathion

Metalaxyl

Methoprene

Oxydemeton-Methyl

Permethrin

Phenyl Methylcarbamate

Piperonyl Butoxide (PBO, a synergist)

Propetamphos (Safrotin)

Pyrethrins

Pyrethroids

Resmethrin

Silica gel

Sulfluramid

Tetramethrin

Tralomethrin

Zinc Phosphide

[power]

No worries Keep Left, I dont know about hydro set up. Pertinant question. Like Luke says I woluld let it run through and dump the water and do it again then another dump. As you dont want to over chemical them. Maybe someone else who has done this before can give you answers.

 

N

[keepleft]

:scratchin did some research and found out all of the following are used to control fungus gnats (larvae)

 

1. Azadirachtin (this is available in oz at hydro stores as azadrench and is a neem extract). Article states that it is safe to use on greenhouse-grown vegetables. Spoke to the mfg in melbourne, he said you flush medium twice in 7 days increments and you just let it recirculate. No harm to plants.

 

2. Bacillus thurengiensis israelensis (ie Gnatrol) - as mentioned by luke above. however it is stated as 'slow acting'. I cant find this in Oz though!

 

3. Chlorpyrifos (trade names include Lorsban, Durban, Agromid, Bullet, Chlofos, Destroyer, Omexan and Panda). This is an Organophophate pesticide (like Malathion) and is the strongest commercial one i could find. I'm not sure where to find it at the retail level?

 

4. Chlorfenapyr (aka Intrepid by Bayer)

 

5. Diflubenzuron (Adept) - long residual activity

 

6. Cyromazine (Citation) - slow acting

 

7. Kinoprene (Enstar II) - slow acting

 

8. Pyriproxyfen (Distance)

 

9. Steinernema feltiae (Nemashield/Nemasys etc). Biological. Beneficial nematode that attacks fungus knat larvae. HOWEVER need to apply before fungus knat population is high.

 

Interesting that Mavrik (active ingredient FLUVALINATE) wasnt mentioned anywhere as a known effective pesticide to be used against fungus knats and larvae. But it seems as though it works based on other peoples experiences!.

 

Also, i'm only 2 weeks from harvest. SHOULD I TREAT them with a pesticide like MAVRIK or just use something a bit less chemical like AZADRENCH, or just leave em be and ride em out! Worried about toxic residue.