larvae/maggots in soil

[Light&Love]

Hey guys

I fertilised my viridis plants with some blood and bone ferts, worked through a half inch into the topsoil, and ever since then ive been getting maggots and these little larvae things moving around when i dig into the topsoil, plus im getting ants on it, and im also starting to notice baby flies creeping up out of nowhere. Is there anything organic i can put in that wont harm the plant? Time is of the essence..

Peace

[Evil Genius]

Hi L&L, that sounds like fungus gnats! Cut down the water! Its always a sign of overwatering! bye Eg

[Light&Love]

Hi L&L, that sounds like fungus gnats! Cut down the water! Its always a sign of overwatering! bye Eg

 

Hi EG, i know its not from over-watering, i do probably overwater a little, i do believe its that blood and bone fert that i put into it, because the day after i put it in, flies have been attracted to it, and ants are somehow finding their way into the pots and carrying the little peices of ferts away, neither happened before i used this fertiliser. My question is now, how the hell do i get the fuckers out, without resorting to unorganic pesticides?

Peace

[AndyAmine.]

Fungus Gnats dont only show up from over watering, it can take weeks of being bone dry before they all die off so if you get them just letting your plants soil dry out often isnt enough because the plant will die before the gnats.

The are particularly interested in organic material and its very common for an infestation to occur at the soil/fert supplier that you then take back home with you, before you know it youve repotting your collection or whatever and you know have gnats everyfuckingwhere. Blood and Bone is a perfect example of what they love.

It only takes one infested bag of soil or plant to infest an entier soil supplier or nurseries stock.

My Local bunnings (like home depot) AND my local nursery often have the little maggoty bastards already in their soil bags or in the potted plants and because they stack the bags ontop of each other and next to all the other brands of soil/fert away the cycle goes.

I picked up a bag of organic moo poo recently from bunnings and ended up with the buggers all over the place, I even checked to see if they were in there because its happened before but I guess they were still in the larval stage and too small to see.

IMO the best ways to get rid of them are:

A: keep your plants very healthy and if in pots keep the organic matter on the lower side as they MUCH prefer unhealthy plants in organic matter (BnB etc) with mould/mycelium or root rot (ive seen them compleatly avoid healthy plants right near to them.

B: Diatomacious Earth but this also kills of beneficial bugs/insects etc. as well.

[Evil Genius]

Well, i assume you have fungus gnats here. Take a look at the picture.

Does the larvae look like this?

Thats a fungus gnat larvae! You usually get rid of them by reducing the water and letting the soil dry out. The larve dies at some point. They are not really a Problem if you manage to find the right balance between the point when the soil is so dry that the gnats die but the plants survive. Not easy but manageable. An important point is to let the soil dry out between watering cycles. But not for so long that the plant really suffers. The more you watch the plant, the more you are able to recognize a thirsty plant! But be careful because a plant that suffers from too much water sometimes can look like a plant that gets too few. bye Eg

[Light&Love]

Fungus Gnats dont only show up from over watering, it can take weeks of being bone dry before they all die off so if you get them just letting your plants soil dry out often isnt enough because the plant will die before the gnats.

The are particularly interested in organic material and its very common for an infestation to occur at the soil/fert supplier that you then take back home with you, before you know it youve repotting your collection or whatever and you know have gnats everyfuckingwhere. Blood and Bone is a perfect example of what they love.

It only takes one infested bag of soil or plant to infest an entier soil supplier or nurseries stock.

My Local bunnings (like home depot) AND my local nursery often have the little maggoty bastards already in their soil bags or in the potted plants and because they stack the bags ontop of each other and next to all the other brands of soil/fert away the cycle goes.

I picked up a bag of organic moo poo recently from bunnings and ended up with the buggers all over the place, I even checked to see if they were in there because its happened before but I guess they were still in the larval stage and too small to see.

IMO the best ways to get rid of them are:

A: keep your plants very healthy and if in pots keep the organic matter on the lower side as they MUCH prefer unhealthy plants in organic matter (BnB etc) with mould/mycelium or root rot (ive seen them compleatly avoid healthy plants right near to them.

B: Diatomacious Earth but this also kills of beneficial bugs/insects etc. as well.

 

Thanks Andy, im worried about them just eating away, getting deeper and deeper into the soil, and attacking my plants root systems.

If i dont take any action other than to let the pots dry out a bit, how long should i try that for? Im just worried that if i stand there and do nothing, they'll just spread to other pots or whatever, leading the the death of my plants. Is that possible?

Peace

[planthelper]

i agree with eg, it's fungus gnats and removing them is not easy, even harder organicly.

the only organic methode is to use nematodes (i might remeber wrong though), anyway there are predators around which will kill the gnat larvae. but i guess that buying those predators is not worth the money and hussle.

i would remove all of the fert and as much of the potting mix as possible without hurting the plant and it's roots tooo much. than i would repot with fresh sterile pottingmix.

another organic controll measure could be the use of diatomaceous earth or even perlite, the idea is to sprinkle the diatomaceous earth on top of the pottingmix, and as such creating a layer which the larvae can't crawl thru, it's said diatomaceous earth kills gnat larvae because the fine abrasive material chokes and clogs up the breathing apperatus of the larvae.

another thing one has to do is to clean the whole area where plants are kept, as it's likely you have many infestations at other pots aswell, they are just not as visible because you haven't fertilised them as much.

the inorganic methode is to drench the whole pot with a water - pyrethrum mixture, but even if you do this, re infestation will occure unless you kill all of the flying gnats aswell, and of course the eggs, which i think are even immune against the spray.

keeping the pots effected much drier is a very good methode to reduce the fungus gnat problem.

sorry above post wasn't ther yet when i strted composing,

and i'm a slow keyboarder, hehe...

Edited December 12, 2009 by planthelper

[Evil Genius]

It´s definately possible that they seriously damage the roots. You could repot in a soil that has very few organic parts as well as no bone/blood meal in it. Maybe some kind of sandy soil that dries out very fast. Maybe this would take them the nutrients to reproduce.

edit: lol planthelper...we just had the same thought. Nice post!

Edited December 12, 2009 by Evil Genius

[AndyAmine.]

@PH:

DE shouldn't just be applied to the top as the gnats will come out the bottom of the pot as well.

Generally DE should be mixed with the soil and then dusted ontop, I also used to tape a piece of fine weed mat or something to the bottom of the pot so that it gets air flow but wont allow them out.

If you can stop them from leaving the pot for long enough it should kill the cycle.

Using crushed perilite was an idea I posted about some time ago, it worked well for the first little while when dusted ontop of the soil but became usless once it got wet for the first time.

Another important note is to use GARDENING grade DE not POOL FILTER grade DE as the latter is next to worthless and MUCH more harmful to humans and animals.

[mac]

I dont have much experience with Knats but Hydrated lime (builders lime) gets a mention to help control knats & fly larvae.

Have a read of this page it explains most of what others have suggested How to Manage Pests

[reptyle]

This is a little left field...but how come there isn't a general gardening tips thread? I suppose it is ethnobotany...gnats in the soil...

[AndyAmine.]

There is one.

It was merged with another thread a while back.

I guess it should have been made a sticky.

[Torsten]

Great thread with excellent information to a common problem!

The DE is definitely the best long term treatment method. Some plants can tolerate a dip in a dilute pyrethrum solution, but be careful as many plants will get root burn from this. One way to avoid/reduce the burn is to do the dip, wait 30 minutes, then flush with lots of clean water soaks. This will kill most/all active gnat larvae and will give your plant roots a bit of a break from being nibbled.

Just one correction to what andy wrote: Fungus gnats usually don't arrive from contaminated soil, but rather the flying adults are everywhere. Applying blood and bone or compost is a great way to attract them and any such application should be accompanied by a sticky trap mounted near soil level. The trap will catch most adults so they won't lay eggs.

[AndyAmine.]

OK thats for the advice T.

I mentioned it because from my eyes that certainly seemed to be happening here on the GC where it is nice and humid and I have defenitly been caught out by buying bags of infested soil that then infested my garden.

I was recently at a landscaping supplier and whole saler to buy some scoria and nearly every pile of soil (in the multi tons) was absolutly crawling with gnats.

[Light&Love]

Thanks for the info guys, i let all my pots dry out, and the little fuckers have been getting out from the holes at the bottom, im sure if i let them dry out completely all will be well, if not ill definitley try the DE method. I think im gona take the first 2 inches of topsoil off thats been mixed with B&B and replace with fresh soil, that way the flies will fuck off.

As a side question, are there any good ferts and nutes that dont attract bugs and insects that'll kill my babies?

Peace

[kindness]

I've had so many of these little guys in heaps of my plants. Cacti and all. Letting the soil dry out has worked for me, I wasn't actually trying to get rid of them - just being lazy with watering over winter. The pots had heaps of the dead gnats around them, (which I guess is another sign that you've got the gnat). All the plants pulled through however, nice to know that DE is an option though.

I use alot of blood and bone too which is probably the cause as stated in this thread. Great advice all

Can't wait to move from this house and start growing my garden in the ground instead of in pots. Some are obviously going to have to stay in pots but I think having a healthy soil working in harmony is far easier when organic matter can be added and good and bad insects can fight it out in their own larger environment than in the confines of a pot.

Another thing I find is my pots outside benefit from all the birds and other insects doing their thing - i.e. birds picking off insects, predatory insects munging out on the bad guys... the bad guys occasionally winning and taking out a weaker plant. Whereas the inside plants don't benefit as much from this.

I had a gnat prob in my loph cupboard and introduced a few daddy long legs spiders in there to see what would happen... they are still living in their now after a few months and getting fat and looking healthy. I don't think they have made much of a dent in the gnat prob though... but may have assisted a bit.

[planthelper]

i guess there are two methodes, one tries to just controll the problem to a certain degree, whilst the other one would be to eliminate the whole infestation all together.

as said, they can fly and as such they can allways reinfest your pot's, so to try to wipe out the colony would be a sisyphus task anyway.

so let's stay with option one, trying to controll the problem to most possible degree.

and adding lime to the pottingmix can help a great deal as i think fungus gnats love acidic conditions.

gnats are far worse often in indoor conditions, often indoors you can see the tiny flies roaming around, and in such case you are well off if you try and suck all the flies into your vacumcleaner and than wipe down all benches.

those gnat flies will try to hide, so stamp your feet on the ground or bang your fist against any walls which might contain crevises or any possible hiding place. the idea is that somehow the gnats respond to the banging by leaving there hiding spots.

the battle against gnats is like any other war,

it gets decided by your arial fighting power, and not landbased, hehe.

in other words, try to kill all fliers aswell, otherwise they might reinfest.

and yes, one of there most prefered hide outs are the drainage holes in any given flower pot.