Gnat Problem

darc · Mar 16, 2012

Hey everyone I recently moved my plant into a new pot and into my grow room. I recently noticed gnats flying around. I also saw some larva in the soil at the base of the stem. I made a apple cider trap and got a fly trap stick thing at walmart. I am planning on transplanting it tomarrow and covering the top soil with sand. Any other suggestions of what I should do ? Thanks in advance!

endive · Mar 16, 2012

[quote name='"darc"']Hey everyone I recently moved my plant into a new pot and into my grow room. I recently noticed gnats flying around. I also saw some larva in the soil at the base of the stem. I made a apple cider trap and got a fly trap stick thing at walmart. I am planning on transplanting it tomarrow and covering the top soil with sand. Any other suggestions of what I should do ? Thanks in advance![/quote]

Sounds like you've nailed down the first steps of preventative maintenance. There yellow gnat traps that work well too!

Keep an eye out for unusual yellowing on the leaves, or very slow growth. It may be an indicator you have gnat larvae at the root level.

I highly recommend Azamax. It is good for foliar spraying gnats/mites, as well as root drenching.

BadKittySmiles · Mar 16, 2012

From a past thread....

Just remember, killing the adults is all fine and good, but they aren't the ones doing the damage... and they only live 5 or so days with their wings, anyhow! Killing and deterring them is a good start...

But their young, which they each produce by the hundreds, live for weeks at a time at that stage, devouring your root system/s!

Just when you think the adults are all gone, your plants continue to suffer, then suddenly you'll be hit with wave, after wave of new gnats! So you need to be sure you treat your medium and provide a powerful barrier, as well.

BadKittySmiles said:

The adults may appear to diminish, or you may only see one or two now, but the larvae thrive by the thousands under the surface of your soil, and they are the ones responsible for the damage. The neem dilutions recommended by manufacturers are usually only just strong enough to kill off lesser/weaker insects, but not fungus gnats, or their larvae.

The larvae burrow all the way through your medium, from the top to the bottom, and they love hanging out in the very base of the pots, where the roots often collect and wrap around the bottom of the medium.

If you're looking for an organic way to discourage them, a thick top dressing of cedar chips actually will work to prevent the adults from burrowing and laying more eggs, without inviting other negative pathogens to disrupt your grow (in fact, it discourages mold/mildew).

Fungus gnat adults need to burrow around through that top soil, to lay their eggs, and they won't do it if there is something so pungent and dis-likable in their way.

To add to the effectiveness, use your neem oil, in slightly higher ratios than recommended (I've done this countless times, the plants seem to enjoy the presence of neem if anything), and drench the sides of your medium, all around the inside-edges of the pot.

This will coat the fungus gnat larvae, and their very favorite hiding spots, and it sticks around just long enough to discourage them from returning, should any brave adults linger.. the adults, only live for just over FIVE DAYS, slightly longer (up to 10 days) in the wild or colder environments, but in a hot grow room their life cycle is sped up surprisingly.

Their adolescents live almost three times the adult lifespan, in your medium, before they even emerge.. this is where it's most important to take action, otherwise, they just keep hatching and maturing, and they keep coming.

Bacillus thuringiensis, is another more natural option I've had much success with, however, you'll want to use it when you haven't used neem for a few days or a week. The neem oil, can kill off the living bacterium, before it has a chance to kill the larvae upon its consumption... the larvae eat the living thuringiensis, assuming that it's a good bacteria-food-source, and it disrupts their digestive function causing them to discontinue eating, and to then starve to death.

Another, more chemical option you have, is Imidacloprid.

It's a last resort, and it is THE most effective avenue, but I don't like recommending anyone to use it on non-ornamentals, even though it is widely considered to be very safe for mammals (it's used in the pet world, in topical flea deterrents), and even safe for some insects.

Generally, it is a lawn treatment, and an industrial fruit, veg, and cereal crop treatment.

'Technically' it's safe, but 'technically' isn't always good enough for those of us actually growing for ourselves and patients!

"A chlorinated analog of nicotine, the compound therefore belongs to the class of neonicotinoid insecticides, and acts on the nicotinic acetylcholine receptor; the chlorination inhibits degradation by acetylcholinesterase. Imidacloprid is notable for its relatively low toxicity to most animals other than insects due to its specificity for this type of receptor, which is found more often in insect nervous systems and zooplankton than that of other animals (exceptions exist, earthworms and a few species of fish, for example). This potentially allows for lower concentrations (e.g., 0.05–0.125 lb/acre or 55–140 g/ha) to be used for insect control than other neurotoxins (particularly organophosphates) and enables its use in applications as diverse as flea treatments for pets, control of beetle larvae in lawns, eradication or prevention of termite infestation in buildings, and other uses where animals and people may be exposed... In rats subjected to a two year feeding study, no observable effect was seen at 100 parts per million (ppm).

The most widely used applications for imidacloprid in California are pest control in structures, turf pest control, grape growing, and head and leaf lettuce growing. Other widespread crop uses are rice, grains/cereals including corn (maize), potatoes, vegetables, sugar beets, fruit, cotton, and hops. Target insects include sucking insects (e.g., aphids, whiteflies, leafhoppers and planthoppers, thrips, scales, mealybugs, bugs, psyllids, and phylloxera), beetles (e.g., longhorn beetles, leaf beetles, Colorado potato beetles, rice water-weevils, wireworms, grubs, and flea beetles), and others (e.g., lepidopterous leafminers, some diptera, termites, locusts, and fleas).

As an insecticide spray, it is used on citrus, coffee, cotton, fruits, grapes, potatoes, rice, soybeans, sugarcane, tobacco and vegetables. It is also marketed for termite control, for flea control on pets, and for household cockroach control. "

As safe as it all sounds.. it's still a harsh, and somewhat toxic chemical if used in higher concentrations, so use at your own risk. Personally, I keep it around to treat my surrounding ornamentals; it's so strong, that its mere presence is usually enough to deter fungus gnats from infesting my entire work space.

If you don't have ornamentals in your work space like I do, I recommend diluting it per the manufacturers recommendations, and rather than using it as a soil drench, just leave small dishes of the solution on the floor, next to your pots..
The adults often hang out down there to drink your run off, which usually contains broken-down root/plant matter.

Good luck! Those little b*stards are a pain, and they do more damage to your crop than you'd ever realize.. your plants may look healthy, they may have some amount of yield in the end, but if you don't bother to kill them off properly those larvae absolutely cripple the true vigor and growth, that your plants would have otherwise displayed.
Click to expand...

Forums

Gnat Problem

darc Registered User

Attached Files:

2012-03-16 00.28.53.jpg

endive Swank & Debonaire User

BadKittySmiles Compassion Support
Gold Member

Share This Page

Network

Forums

Help

Find Us On

Useful Searches

Gnat Problem

darc Registered User

Attached Files:

2012-03-16 00.28.53.jpg

endive Swank & Debonaire User

BadKittySmiles Compassion Support Gold Member

Share This Page

BadKittySmiles Compassion Support
Gold Member