What are the signs that the larve has attacked the roots on cuttings? Ive seen just a few Gnats around my figs cuttings. No infestation but Ive seen 5 or 6. Most I saw when the cuttings were inside. Now that Ive moved them out side in the shade Ive only seen one or two. So how do you know its gnats that are responsible for cutting decline?

If you see one gnat, it's all over!  They thrive inside and outside.  Drench the plant with BT or some other larvae killing solution.  They are hard to get rid of, but if the leaves are shriveling, and things look wilted, it might be too late.

One gnat lays a lot of larvae, and they go for the roots, then they hatch!  Then they lay! 

They will not lay eggs in sand, so top your pots with an inch of sand, but they are clever and small, so they find a way to lay in the drainage holes.  Some stretch ladies nylons over the pot to cover the holes.

It's war!!

Good luck!

Suzi

WHAT!!! Dont tell me that! Would removing the cuttings and repotting in sand be an option? If drenched with a BT solution wouldnt cause root rot from the soil being to wet? Decisions......

It's very sad, and the gnats don't limit themselves to one pot.  We have all been in your shoes, and mostly it's not a happy ending.  Now when I water, I always use BT in the water.  Hard lessons!  One drench won't cause rot, but many larvae will destroy your roots.  You can try putting BT dilution in a bucket, and gently swishing untill all the soil falls off, so you have rinsed off any latent eggs in the soil, plus killed the larve.  THEN, repot in fresh damp potting soil/perlite, or just straight perlite like some here do, and water sparingly but always keep BT in the water.

There is a ton of info here and on the web.  Do some searching.

Good luck!

Suzi

What is BT? I also have a infestation

Here is a linkto it.  You can get it at any Big Box or Nursery.  It's biodegradable and won't hurt anything but the larvae.

Bacillus thuringiensis

It sounds like you might be overwatering Suzi. Check this out:

Does Gnat Larvae do little or a lot of damage to established trees in pots. I do know they kill cuttings....(they get me mad..LOL)

We inherited a plant from JD's mom's estate.  It was a big potted tropical tree.  We had it in the house, and I noticed the gnats around it.  Didn't think a thing about it until they attacked my growing cuttings (in another room of the house), and killed them all. 

That tree no longer is in the house, and after a lot of soaking in BT solution, the gnats are gone.  The tree thrives.

Rooted, leafing cuttings are just babies and very weak and susceptible.

Blueboy1977,
Fungus Gnat larvae reside in the top 2-3 inches of wet soil, the adults are attracted to moisture, fungus and decay, where they lay eggs. If you keep the top of the mix dry, you can reduce or eliminate Fungus Gnat infestation. I use readily available Mosquito Dunk for their treatment it's encapsulated BTi. I grater the Donut, mix it with water or mix it into the top 1 -2 inches of damp soil, where the eggs are laid and the larvae emerge and are active. If you use Gnatrol or similar BTi products it has to be reapplied in 7-10 days to work with their hatching cycle. If you have fungus gnats it is a sign that the soil or mix is too wet especially for fig cuttings. <and they are probably already on the decline, due to excessive moisture>

From what I can tell they are mostly a danger to the cuttings, once a plant gets gallon sized it takes more to kill them. I have lost so many well rooted cutting to those stupid gnats... I went to war!! I added soap, gnatroil and another BT and hydrogen peroxide to the water, I got fly paper and these strips for windows that I stuck to the inside of the tubes, before I found those I strung fly paper in the tubes..I have been gnat free for five weeks... and have only lost a couple of cutting to usual causes. If you have one showing signs of dieing they way you find out it was gnats is you find the larva eating the stems under the bark.. they are wicked gross...
http://www.ext.colostate.edu/pubs/insect/05584.html

http://farmerfredrant.blogspot.com/2010/12/fungus-gnats-on-houseplants-how-to.html
http://www.ppdl.purdue.edu/PPDL/images/Fungus-gnat-larvae-feeding.jpg

Good luck!!

there must be natural predators outside, as when I finally had a fit and threw them out there to do whatever, a few of the cuttings actually made it alive.  when you see 5 each darn thing lays some 300 eggs of very hungry babies, every 2 weeks, the cycle retarts, now with over 300 laying 300 eggs each.

the trick is not to have any adults. This year so far, it is fine for me. I have not seen any adult around, and got this "Tree Tanglefoot"- Insect barrier (Natural Gum, Castor oil, Carnuba Wax) it comes in a yellow tube (like large toothpaste).  I spread the gooey paste on yellow paper and put little flags everywhere.  I have cider/vinegar traps, I also have those long ugly fly traps everywhere.  And keep the cuttings and cups inside of buckets as long as possible. 

So far, I am doing better with them, but I know soon I let my guards down they will be back. They are in the yard, everywhere! the chickens are controlling them a bit.

they are horrible creatures!  The plant has to be strong, super strong to handle their munching.

signs are wilting and not recovering, pull the cutting out and all roots are gone.

Thanks for all the replies and suggestions. Im going to be heart broke if loose alot of these cuttings. I got some really good varieties rooting:( Im going to pull a few when I get home and do alitte inspecting and see whats going on.

Also moving everything inside tubes also helped...

Well,  don't just pull from the soil.. open the soil enough to inspect.. if you drench them in soap water or the other mosquito larvae mix, you may have to remove some of the soil and replace with dry soil to compensate the moisture...or put over a well venting area to air it out quick. the problem is that the larvae crawls inside the cutting eating it from inside out, so applying anything to the soil does little to the healthy ones munching the cutting from within. If that is the case, just cut the loss and stop suffering trying to revive them, it is a lost cause.

I learned the hard way.. when I see the signs, I put everything in the microwave and zap them.

There are many studies about soaking roots in water for 10 minutes or so to kill nematodes.  I wonder if that treatment would work for larvae infested roots?

Here are a couple interesting studies:

UC Davis Hot Water Treatment

Garden Web Forum Thread

Vegetable Diseases Cornell

I remember I accidently killed the FMV virus by frying the roots of a Panache.  It was in a pot on concrete by a wall in the hot desert, and for 3 years it never had more than 2 leaves.  Finally Jon told me what was happening, told me to flood the plant a few times and then put diluted Miracle grow on it.  Worked like a charm!  FMV gone.  But my landscapers killed it with wrought iron spray...... GRRRRRR

Just wondering if heat would work, but NOT RECOMMENDING IT!!

Suzi

bb1977,

Photos please.  Also if you have fungus gnats flying about try the spray below which Lowes and Home Depot usually sells.  Fungus gnats can make you crazy.  I had some last year, but none this year, go figure.......except I drenched the soil mix /cuttings with Gnatrol solution at the get go and didn't wait for gnat sign.  Maybe that was the trick, preventative rather than reactive.

How much Hydrogen peroxide OR soap would I have to put in water and soak my cuttings

Well I pulled a few plants and looked at the roots and the plants that were wilting had no roots. They rotted off! I checked 2 CDDN and 2 Texas BA-1. All the roots were rotted off. I cut them again a couple nodes up and the cutting was still green so put clonex on them and put back in peatmoss in a plastic tub. Hope for the best. 2 other CDDN had some pretty healthy roots on them. The soil is far from being too moist so it's got to be the gnats. I purchased some BT to water the pots with. If I nuke the soil I pulled out of the pots can it be reused? Or should I make a whole new batch of soil? Last season I just used sphagnum peat moss and perlite 3-1 ratio and had none of these problems! This season I use Scott's potting soil which had some fert already in it. I'm thinking I can rinse and repot all the plants in the 3-1 perlite peatmoss mix and when I wet the peat use BT water solution? I don't want to lose another plant!

Hi Blueboy,
Perhaps the roots rot for another reason - don't get yourself crazy for gnats.
Tame an aluminium foil and cover the surface of the pots with the most reflecting face turned to the upper light.
That seems to disturb the flying gnats - that's what I did for now . I avoid as well over watering and I water from the bottom - My cuttings haven't been watered for 8 days now.
Are the cuttings exposed to proper light to sustain the green growth ?
Just ideas ....

Ekierk I put a generous squirt, about a teaspoon into a gallon jug. I put about a cup of HP into a gallon...