Fungus gnat control with imidacloprid insecticide

[Kelby]

I had a thought today on a different way to control fungus gnats (Gnat Nix, Mosquito Dunks, etc being other options). Imidacloprid is a systemic insecticide that is applied as a soil drench. According to UC Davis it is effective on fungus gnats. The problem is that being systemic insecticide there is the possibility of the insecticide winding up in the fruit, though it has been approved for use on most fruit trees (see this product from Bayer ). According to Iowa State, there is a minimal amount that winds up in fruit, most of the insecticide remains in other tissues. May be worth investigating more.

It should be said that imidacloprid is a neonicotinoid insecticide that has been under fire from some as a possible causal agent in bee population declines and is restricted in Europe. It is also toxic to people in high doses (as most pesticides are).

So, there's the idea. I don't know if I will be trying it out on my fruit plants, personally. I have used it on houseplants without problem when other tactics have failed.

[pppldj]

Even though it is systemic, most of us would only use such a product during the rooting phase and discontinue use very early. By the time we were to harvest figs for consumption, it should be long gone. Even if it were still in the plants system, how many figs are most of us really going to get off of a newly rooted plant?

[Kelby]

I had thought about that. Plus it can only be used once every 16 weeks, so a minimal amount is in the soil.

[smatthew]

Imidacloprid can only be used on fruit trees that are non bearing. You would need to remove all fruit for a period of 1 year.

[don_sanders]

Bayer Fruit, Citrus & Vegetable Insect Control is imidacloprid with a low dose. Looks like post harvest interval is up to 30 days.

[pppldj]

Reading more about it, I see that it breaks down rapidly in water that is in the presence of light and less slowly in absence of light. Half life in soil is 6 months. Still, a small amount in a cup, I think that the plant would outgrow it. I think I remember that Bifenthrin is effective on fungus gnats and is not systemic.

[drew51]

Hydrogen peroxide works for me and adds extra oxygen to the roots, also takes care of mold. I just put it in all water applications indoors as a matter of routine. It's super cheap too and goes a long way. Works too! About 2 tablespoons to 1/2 cup per gallon. Use the higher dose for a bad infestation.
It takes a bit to work, all eggs are killed, so once current flies die, they will be gone.

[Rafaelissimmo]

bti/gnatrol works well and while it may disrupt some of your soil ecology at least it is 100% safe, organic etc. why mess w a good thing?

[Kelby]

Just pondering back up solutions, you never know what will happen!

[cwujek]

As someone who has farmed both chemically and organically, please do yourself a favor and avoid buying products such as Imid. It's not worth the risks to you or the environment. I've seen what chemical farming has done to families in my area, and I would get rid of all my plants before buying another systemic pesticide.

https://www.beyondpesticides.org/assets/media/documents/pesticides/factsheets/Imidacloprid.pdf

[drivewayfarmer]

Gnatrol works so well , you really don't need to use something with so many downsides as Imadacloprid just to control fungus gnats.
Not saying you can't or shouldn't , but really seems like using a canon when a well placed dart would get the same result with no potential unintended side effects .

[don_sanders]

Isn't it one of the most commonly used pesticides? I'm guessing we are all basically bathing in the stuff even if we aren't using it ourselves.

Gnatrol and physical barriers have helped me a lot but I still haven't been able to eliminate them inside.

For the most part, I grow pretty organic so I haven't resorted to real pesticides yet but I have considered it more than once.

[LouNeo]

I opened a bin today that had some small flies in it. First time ever, whats the best way to get rid of them? Does the Hydrogen peroxide work? I will spray the surfaces of all my cups tonight if it does. Thanks in advance, trying to catch this early.

[don_sanders]

I've never tried hydrogen peroxide but if it does work, you would need to do a full soil drench to eliminate them from the soil. If you see a few flying around, most likely, your soil is infested with tons of little larvae crawling around. Very small, hard to see, could be anywhere in the soil from top to bottom or crawling around under the bark on the stems.

If they haven't started rooting yet, I'd replace the soil with something sterile.
If they are established enough for a full water, I'd use gnatrol or something like imidacloprid if you aren't organic. I'm going to give Neem cake a try.
If they are rooted and delicate, I'm not sure that there really is anything that you can do but wait it out. Maybe inspect and isolate any that seem to be infested. Sticky traps, a good 1" layer of sand on top, and preventing any access to drain holes can help slow down the spread as well but won't eliminate.

[LouNeo]

I appreciate it. Its 1 bin but.. I need to read up and get in front of it quickly.

[COGardener]

Last year I used some carnivorous plants and a small army of baby jumping spiders... Problem solved!!!

[Blackfoot12]

Lou: My wife brought a plant inside at the end of the summer a few days after a heavy rain. Shortly thereafter I had a population explosion of fungus gnats. I mean there were hundreds and they seemed to be everywhere. During the summer i had lost a precious seedling to fungus gnats (not a fig). So, I was very alarmed. I mixed up gnatrol and started applying it to everything. (Got rid of the plant my wife brought inside). Over about 5 weeks the gnat population steadily declined. I actually saw a gnat for the 1st time in several weeks the other day. 1 gnat! So there is no question gnatrol works.

[LouNeo]

Thank you, I will see what im able to accomplish. Im hoping there isnt an army waiting for me

[Kelby]

Just to bump this up, my fungus gnats were getting pretty bad so I applied some granules of imidacloprid ( http://www.bonide.com/products/insec...ic-granules-ic ) to my pots with cuttings in them. 12 hours later there are no more gnats.

[newnandawg]

Kelby, that is great news. I guess you will have to wait to see the effect
on the larvae.

[don_sanders]

How did the imidacloprid work out in the end? Did it eliminate them completely?

[Evildeadguy]

i use Gnatrol works great to get rid of them and its safe to use and to keep them from coming back use Sand as a mulch few inches on top of the potting soil keeps the adults from laying there eggs

[don_sanders]

While I've used and like gnatrol to keep the population down, it doesn't seem to completely eliminate them for me. I was looking for something a little more permanent and perhaps cheaper as using gnatrol on a regular basis adds up.

[Evildeadguy]

well the cheapest way would be to use Sand as a Mulch if you haven't already tried it. something like in the link below
http://www.homedepot.com/p/Mosser-Le...1110/204370350 works great at keeping them away

[Jamie0507]

I tried the sand last winter when those nasty buggers infiltrated the media I was using for my cuttings and I think I heard one actually laugh at me when I added an inch or so of sand to the top of my cupped cuttings! Lol! J/k!!! 😉Seriously though, perhaps the layer of sand needed to be a thicker.. But those buggers didn't mind it in the least.. I think they just looked for the drainage holes in the bottom of the cup if it did bother em at all.. Although I don't like the idea of harsh chemicals, I just might try this if Kelby reports back that it was effective.. BUT I think prevention this year will be my biggest focus to start out with for sure.. 👍🏼

[Evildeadguy]

I would say around 2 or 3 inches of sand should do it. And if the soil is staying to wet that will keep them coming let the soil dry out some before watering again if that doesn't work you will have to repot them in New soil clean the root system off good before reporting them in New soil

[COGardener]

I added carnivorous plants to my garage greenhouse, it took awhile but the gnats disappeared and have never come back.

[Jamie0507]

Nice! I bought a few for my lil guy last month from lowes! They already have sprouted 3 "mouths".. the better to eat more fungus gnats with! Lol plus my son gets to watch his carnivorous plants grow fat & happy if those buggers do make it in again this winter.. 👍🏼👍🏼Great idea Scott, thanks for sharing