Fungus Gnats

[Ann B.]

Anyone ever had a problem with something called fungus gnats? One of our members is apparently having a problem, and I wondered if any of you have ever dealt with this problem?

It is new to me, so I can't really help....

[sewfarsewgood]

Go to http://ohioline.osu.edu/hyg-fact/2000/2114.html for more info. Kill them with a harmless pyrethrin spray. Use sterile potting media to prevent.

[Plant_Guy]

I had a swarm of these gnats not too long ago. I bought Shultz' Expert Gardener insect spray for houseplants and sprayed every plant I had. In minutes, no more gnats. Several days later, I still do not see any.

TomG. - aka Plant_Guy

[careplus]

Hi Ann,

I didn't think these would be a problem in "natural" gardening.

I had a terrible problem with them when I was doing aquaponics. Every breath you took, you got them in your mouth, up your nose and just about every other orifice you could think of.

The gnat, in itself, is not a problem... a nuisance but not a problem. BUT!! The gnat is an adult. The problem is with the babies. They kind of look like a mosquito larvae and they will attack and eat the root of whatever it is that you have growing. There is a product called Gnatrol that will quite effectively control the larvae. Control the larvae and you will control the gnat.

But, have the person who is having problems research on their search engine fungus gnat, gnatrol, etc. for there is quite a huge difference in price of some of the products. I bought Gnatrol and found it to be quite effective.

Steve

[Dazed_Lily]

After reviving the damping off disease thread, I decided to search on damping off disease on the internet and ran into another arch villain--the fungus gnat. That led me back to another search and another good previous thread on Landspro. I never knew what they were called but just that sometimes I get little black flies buzzing around plants or sometimes water faucets. I figured they were some how connected to plants and dampness but didn't know they were nogoodniks. Well, they too are not conducive to seedling starting. I suspect my vectors are 2 spider plants that spent summer outdoors and were just whisked indoors without removing dead tree leaves, etc. Well, at least I'm realizing more things this year :)

Below is a copy and paste from the internet:

These tiny, black insects seem innocuous enough as they buzz over your plants. While the adults rarely cause any problems to plants, if the young larvae are in large numbers, they can damage your seedlings. Fungus gnats search out moist soil in which to lay their eggs. When the eggs hatch, the larvae will feed on the roots of your plants. Healthy seedlings will often be able to withstand this feeding but any seedlings that have small root systems like onions and leeks and those that are showing symptoms of nutrient stress can be put back quite significantly.

The easiest way to prevent fungus gnats is to water your plants properly. Overwatering, which causes your potting mix to remain moist for extended periods of time, seems to attract fungus gnats. If your plants are already infected, allow the soil to dry out between watering. Alternatively, sprinkle a ¼" of sand on top of your soil to confuse the adults. Since the sand drains water quickly, it can sometimes trick the adults into thinking the soil is dry.

Potting mixes containing peat seem to be particularly affected by fungus gnats. If the problem is reoccurring for you, think about switching from a peat-based mix to one that only contains perlite and vermiculite. Lastly, if the adult fungus gnats are bothersome, trap them by making your own sticky trap. The adults are attracted to the color yellow. Make your own sticky trap by smearing Vaseline or Tanglefoot on a yellow surface and hang it up close to where the adults congregate.

[Ann B.]

This is the first year that I have ever spotted them. There weren't very many, but enough to make me concerned.

This is also the first year that I did not soak my peat moss in boiling water. Some my laugh at that approach, but from now on my seedling mix will receive a very HOT bath.

You see, I use the big packages of peat to make my own seed mix. Once opened, it is subjected to whatever decides to make a home there.

I guess if boiling water works for me, it simply works for me. I am not real keen on the idea of putting peat in my microwave or oven, but I am told that also works.

But I even hate the idea of having those bugs near my seedlings or cuttings even worse!

[Bigoledude]

Mixing a "Mosquito Dunk" in your water will kill the maggot of the fungus gnat. We had a horrible infestation of these disgusting critters.

All my potted amaryllis plants (about 40) and my seed flats, get watered from a bucket with doughnut-shaped "Mosquito Dunks" dissolved in it. Remember that dunks are used according to the amount of square feet of surface area in your pots and flats. One dunk will treat 1-5 square feet. The Bt stays near the surface and lasts for at least 30 days. It is effective only when wet. I have never seen any fungus gnats since using dunks.

A typical black nursery-3-gallon pot has about 78 square INCHES of surface area at the top. Which is a little more than half of a square foot.

The active ingredient is a bacteria of some kind that causes the gut of the maggot to rupture. BT is harmless to humans, plants and non-insect pets.

[sue salley]

Ray, That was interesting. I would never have thought of that. I had more of a problem in the greenhouse that I do growing out of doors. May be the difference in the watering as I water less often than some people do. I try to let things dry a little before I water, not just water whether they need it or not. Epsecially the gallon pots don't dry out as quickly.
Now what about those little fuzzy white things that fly around looking like cotton lint? I've killed several today. They are bad guys aren't they?

[lbfoss]

I haven't found anything online to support this, but I used a spray bottle with 1/2 water, 1/2 hydrogen peroxide (medicinal) and the moss and fungus knats disappeared from my flats and this didn't seem to bother the seedlings at all. I have been cautious about recommending it, but so far, I haven't killed any plants, just moss and pests...........Cheap, easy.

I also pour boiling water into my potting soil when I first get ready to stick cuttings. I swish the cuttings in a dribble of chlorox in a large pan of water and rinse them off i running water before I dip them in the rooting hormone and stick them in the (now cooled) potting soil. seems to work fine.
Linda

[haweha]

Peat based substrates are principally dodgy of being contaminated with these potentially fatal maggots of this little fly. Because the plastic bags are not hermetically closed or /and damaged and often they are shelved in the garden center for a prolonged time :rolleyes:
A treatment in the microwave oven is also helpfull then.

One fungus gnat dame is capable of laying up to 200 eggs in its short life, and she will distribute these carefully in aliquots of 20-30 over the substrate area.

I cover my seed beds with a granulate which permanently releases its agent chlorpyriphos over 2-3 months. In Germany the brand is "Nexion Neu" from Celaflor, alternatively "Ridder" from Bayer, and I guess that in certain transatlantic countries (as viewed from my German stand point) "Dursban solid" from DOW might be available - but it cannot be excluded, that Chlorpyriphos be (already) banned in some of these countries.
A granulate which contains the systemic agent Imidacloprid should work very well, too, for example Lizetan-Kombigranulat...

[Ann B.]

Thanks, Hans!

I definitely have some learning to do when it comes to pesticides. If we have another year like this one, I need to figure out a way to rid of those horrid grasshoppers without harming my beneficials.

Several times, I have spotted a baby praying mantis in my greenhouse. He was very tiny the first time, about an inch. This last time, he is about 1.5 inches long. He comes out to check things out when I turn on the cool mist system.

It's really funny to watch him. Sometimes, he wants to climb on my fingers and sometimes he doesn't. I suppose he just wants to prowl.

Hans, since you are a biologist and understand all these chemical names, please keep us posted if you see brand names associated with these insecticides AND are available to the home user.

So many things are being banned from use by anyone that is not licensed to use them, and I do understand that is because of misuse by the less knowledgeable.

BTW, IF I can, I will try to get a picture of my baby praying mantis. He is way too COOL! And NOPE, I don't know for sure that it is a HE, but for now, that will do...

Thanks, Hans, for the knowledge you so graciously share!

[Tom]

Spectracide 7000 Dursban Granules contains chlorpyrifos

Those big grasshoppers are easiest to control in early summer/late spring when they are small. The will not hurt you, so just pic them off and step on them. However, they do sometimes produce a toxic liquid that may make you sick if it gets on your hands and then on your food, so wash hands or use gloves.

[Ann B.]

Thanks, Hans! Thanks, Tom!

Pardon my slowness. Sometimes, it takes a while to sink in...

[Rebecca]

Don't know why I missed this post earlier, but anyway. . . . you can determine the sex of mantids by their color, even the very small ones! Males are tan to brown while the females are always green! Isn't that just amazing!

As you know, I maintain a large "heard" of mantids throughout my various flower beds and seldom see very many males as they stay hidden until mating season, but I do have a lot of females! I've also been noticing quite a few very tinys ones just in the last couple of days. Appearently more eggs have been hatching out as the season has progressed and more food is available. I am hoping for a bumper crop of frothy egg cases this fall and if anyone needs any for their gardens just let me know and I might be about to send a few to you in late fall.




Rebecca

[sue salley]

I've seen a couple of more mantis in the last few days. Mine are all girls so far!

[Ann B.]

Okay, it has been awhile, and I have been hither and tither...

Girls are green and boys are brown?

If that is the case, then I rescued a boy in the garage. I carefully cupped him in my hand and took him to the greenhouse for a feast.

When I got to the greenhouse, he didn't want to let go of my hand. That was the same case with the brown, smaller one that ventured out when I turn on the cool mist.

So, please... Refresh my memory! Is it the males or females that befriend you?

Rebecca, if you have extras of these, I would love to have more. They are so cute! I have lots of lizards, some frogs and a few snakes (argggg***), but not very many of these friendly critters. I would love to have more!

[haweha]

From what I have seen on the web, they are at least very bizarre.
Some are equipped with wings which are so beautifull that these appear to be stolen from butterflies :eek:

As I am not so familiar with the degree of sex dimophism in mantids I would take into consideration that the brown and green specimens belong to different species.

[Ann B.]

Very interesting...

I didn't realize there were so many different species of the Praying Mantis!

Gotta tell you, though... There were a couple of websites that I found which will sort of freak you out. One told how the female will devour the male after mating!:( :( :(

Another showed a vivid picture of a huge green one eating a hummingbird...

I used to see a lot of these, but I suppose I either don't have as much time to venture around my gardens (or is it the HEAT?) OR my lizard population is devouring them.

The little ones are cute and friendly, and I will let them fend for themselves. With one exception... If I catch one, he goes into my greenhouse!