Fungus Gnat: Information + IPM

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Tha Dank Hoarder
IPM Forum Moderator
warning: work in progress! Shoot i know i suck at spelling . all i can do is try! PM me suggestions or if u see obvious flaws in my wording/spelling. Key is like all these IPM/SOP i wanna make sure we got a SOP that everyone can understand and is safest/best for a grower to use.

BUG ID for Fungus Gnat and simple ID confirmation (many species and bug look very similar )

Minimize moisture under the benches to reduce breeding of fungus gnats there. Ample moisture favors development of fungus gnat larvae. However, existing larvae may attack plant roots if pots are under watered. Depending on level of fungus gnats, apply either a pesticide or biocontrol under benches to minimize fungus gnat numbers prior to starting crop. High numbers of fungus gnat larvae can cause serious damage to plant roots. Shore fly larvae feed only on algae and can breed in standing water. It is important to be able to distinguish between the two insects for control purposes.

Fungus gnat adults are delicate black insects usually less than 1/8 inch long, with long legs and antennae. Their wings are clear, and have a distinctive Y-shaped vein that distinguishes them from shoreflies (both are about the size of fruit flies). Fungus gnat larvae are slender with clear bodies and a black head capsule."
"Shore fly adults are more stout and usually larger than fungus gnat adults. They have short legs and antennae, and dark wings with clear spots on each wing. Larvae are yellowish-brown, maggot-shaped, and do not have a distinct head capsule. Larvae of both shore flies and fungus gnats are found in the surface of the growing medium.

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More FG Pics (adult)
FG Larvae

"Fungus gnats aka FG are small (2–5 mm long) mosquito like flies with dark wings, delicate legs, and long antennae. They lay their eggs in soil, and the eggs hatch about 4 days later. There are four larval instars that increase in size up to about 0.33 inch (8 mm). Larvae are clear, with visible internal organs, and have shiny black head capsules. Initially larvae feed on root hairs and algae; later, larvae may feed on the insides of roots. When populations are high, larvae may bore into larger roots or stems that are in the soil. Larvae will also feed on leaves touching the soil.

Damage: Larvae usually feed on roots and algae within 1 inch of the soil surface. Root feeding by larvae can allow entry of plant pathogens. Direct damage through root feeding can cause wilting even though the plants are being sufficiently watered. Damage is particularly severe in propagation areas, in seedling flats, and with especially sensitive crops. Adult fungus gnats also disseminate soil-inhabiting pathogens on their bodies and in their feces. Fungus gnat adults can be a nuisance when present in large numbers."

Example of adult FG VS APHID

The Key with success on keeping Fungus gnats at bay and if not eliminated is knowing this pest can easily like many pest become a issue and by the time you see adults its a major issue. exp if you are not daily scanning your room for pest pressures and looking for specific things to see if its happening to change your mode of attack and ipm. what i suggest to anyone is have yellow traps from early stage veg and have them every few feet and place the yellow trap card and key is have it close to medium or sitting on it ( i flip the side after a week if sitting on medium) . key is look at the card daily and see if your getting more than 3-5 per week. if your over 5 adults (pic above) you need to go into mode "kncokout" but also multi stage attack the FG for success meaning attack the larvae stage to Adults and inless you want to use toxic aka imiclapradid or similar ( more i tested safer alt no need, will explain later .

the other issue of IPM on FG is not a product but if not best thing for preventing FG is making sure your first 1-4 inches is as "dry" aka not anaerobic but also has constant airflow ontop of the medium . this action t will give roots/bennies air but also FG adults a way harder time to be able to hatch their eggs/larvae. having super wet soil is a win for them but like man y pest it takes very little pest pressure to start a army. key is knowing exp in certain farming like soil and organic no till. its gonna happen. but like nature defenses theres def a successful and workable solution to fungus gnats. shoot making sure airflow and not to much watering is also plants health success so its a good policy none the less .

IPM/Knockout guide:
if pest pressure is showing adult FG above "low" apply =

Baby FG/larvae IPM = Get 50 million nematodes (50million = up to 50 gals water) =stronger count per gallon for larvae and drench apply this if lower than 50 gal, just do a good judgment based on ur rooms usage and more concentrated def the better ( i make mine 30-40million gal max. and it works everytime ). Make sure to keep them (nematodes/they have expiration date )in fridge and u must use whole package than and there. also make sure to have super low ppfd ( light strengeth ) and have the reservoir no npk related and cleanest u can use ( meaning no city or water that isn't suitable for bennies/fungi). a good suggestion is pre-drench before u apply to almost runoff and than drench in ur nematodes , this will save ya a bunch of % to get full coverage but also guarantee your not having any dry spaces in the medium . what i do is also prepare you will see some fg by based starting flower-mid and if soil/non hydro apply it than because even if u saw fg at start its the age of the cycle if you apply the nematodes and rove at start flower stage aka flip you can than guarantee by cycle the fg have no way to win vs i would apply at start or when i first saw erm and than have a issue and have to get a 2nd purchase ( i disagreed with bug companies on that). another thing is if u got multi grow rooms like one for veg and one for flower, ill on same day use the nematodes and make sure all mediums get it. along with my roves

alt b for larvae IPM BTI (Bti is short for Bacillus thuringiensis subspecies israelensis.) = used many cycles of BTI as IPM ( both granular and liquid ) and issue i see even when done correctly the cost vs nematodes isnt there and when i only relied on that plus traps i seemed to still have issues? i also questioned to multi bug companies " views on bti for FG?" majority said it was not as good as other products and they all sold it". cost nematodes and roves and applied in start oif flower even if pest pressure is there if applied correctly those fungus gnats are doomed. trialed outdoors multiple times but also indoors and now i seem FG proof even if outdoors the FG is attacking the zones.

2. Adult FG IPM for FG = Rove Beetles , this will be your mode of defense and attack for the adult stage fungus gnats and other medium based pest/bugs . also another bonus for them like many medium based predators if organics there they will chow down on organic material. sprinkle the rove beetles after watering ( i suggest 2x sqft rates if pest pressure "high"). Shoot I even heard they will eat ur sickly/old worms.

alt b/extra for Adults is hypoaspis-stratiolaelaps-scimitus( Roves recommend by wholesalers for IPM of FG indoors or greenhouse vs OD because rove will "search" and u def can lose ur populations vs indoors and greenhouse where they will stay even if no more pest if dead/organic material is there. shoot i made it a test last few rounds to apply the nematodes only and roves every 2-3 rounds because i saw both my h miles /Hypoaspis &roves still inbetween cycles. My suggestion for ALT B bug (outdoors or 2nd bug to fight) is Stratiolaelaps (Hypoaspis). tried both and they seem to like the notill and stick around in which saves alot.

3. apply yellow traps as pest pressure scanner , daily scan the cards but key is like any pest u want to catch and stop the adults from making more. key is prevention but also none to low populations. i like to switch sides or new card every week inless cad is clear of FG

4. Like stated above keep airflow on medium as much as u can & let medium dry out in-between waterings = helps living medium and also prevents many issues including the FG.

5. NOFLY! If Fungus gnat is at heavy pest pressure infection i suggest if your crop is important/commercial to also apply this , like suggested for nematodes is u need 100% saturation so drench ur npk or water before and get it right before runoff. than apply NOFLY to the first 3-6 inches of ur pots. this mode of action is the NOFLY fungus will attack swiftly and kill but also make the dead insect a host to infect any other pest. safe but also a amazing IPM and knockout on so many insects. i would apply this over any tradional or dangerous and it will if not wipe em out better and no resistances issues like many toxic or traditional pesticides have issues with. if it was me i would apply this first before the other biocontrols and than do those 3-7 days later. ill email NOFLY and ask what they think of best way and when!

"When spores of NoFly WP come into contact with the insect pest they attach to the body and begin to grow almost immediately. Once the spore germ tube penetrates the host cuticle, fungal multiplication takes place through formations of hyphal bodies in the host hemocoel. The NoFly microbe mechanically disrupts the host's internal organs and initiates tissue necrosis. This leads to lack of feeding, inactivity and eventually death. Insect pests sprayed with NoFly WP stop feeding in about 24 hours and are killed in about 5 days. "

*Great Biocontrol/Bug wholesaler, Back them 100%

Worthy Video info/ipm about FungusGnats :

amazing info on biocontrols/nematodes:

Worthy Reads/Links Related to Fungus Gnat for INFO/IPM:


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