Ok, I seem to be having a problem with those darn fungus gnats again... and a couple of years ago when I had this problem I replanted all my plants into a coir based soil.... (I think it was Denise who also grows in coir so I thought I would try it) anyways got away with it for a couple of years and all of a sudden the darn things are back... I bought those stupid yellow sticky sticks things ... but my question is.... I read somewhere and I may have even used the product before - but I read that you can use BTK to kill the larva of the gnats... I even have it but I used it on my african violets - ... will this BTK do anything to my hoyas or is it safe for them? I would hate to water this stuff into my plants and kill them... but I hate those darn bugs too!!! Any one know what I should do? (by the way - I am trying my best to let my plants dry out a bit too)
I am no Hoya expert but I am good with plants and grow all kind of stuff. Generally if plant is kept humid or soil is damp too long WITH poor air circulation ,they get fungus. Also some need sunny area in addition to air circulation.
I think Alka hit the nail on the head there...the only time I've ever had a problem with fungus gnats is in the winter, when things tend to be more closed up. Inside the house where I keep all the plants ( since I have a Kitty that thinks all my plants are chew toys ) I keep a ceiling fan on just about 24/7, plus windows open as weather allows...same in the greenhouse, exhaust fan and another drawing fresh air in and doors/windows open as weather allows.
Those little fungus gnat sticks work great tho if you do get an outbreak. I don't like to use them in the greenhouse tho if I don't absolutely have to as the cute little green lizards and tree frogs go after the bugs stuck to them and then meet the same fate..
Name: Carol Noel Hawaii (near Hilo) It's all about choices.
Lynn - LOTS of posts/threads re: BATS (Bayer Advanced Tree and Shrub).
I get fungal gnats in my kitchen....none in my yard or greenhouse. Peraps your medium is too dense and fungus starts in the soil? That would be my first line of attack. There is another product I have heard about called Gnatrol.
If BTK is Bacillus Thurengensis base...it cannot hurt the plants. I use BTI (BT Israelensis) in my garden against mosquito larvae.
Name: Laura Gardiner Manitoba, Canada You can't 'un-ring' a bell.
The fungus gnats lay their eggs in the top 1/2 inch or so, of the potting medium. The most natural remedy I can suggest, is to top off your plants' pots with a layer of aquarium gravel. This confuses the gnats, and they will not lay eggs in the sand or gravel, because there doesn't appear to be any food for babies, then.
I know they are not really harmful to mature plants, but I live in close quarters with mine, and I cannot stand to have BUGS flying around my living space.
I have not had a fungus gnat outbreak for quite sometime. I REALLY let my plants dry out between waterings...
I know MJ & I have discussed how my solution is not practical for her situation, but there is more than one way to eat an apple!
(I really didn't like the cat euphemism, so I made up my own)
"When you have only two pennies left in the world, buy a loaf of bread with one, and a lily with the other."
- Chinese Proverb
I hate gnats. Fortunately, they don't harm, people, or for the most part, the plants. They are annoying, but in the final analysis, fighting them may not be worth the costs of the effort. Every day I am asked by customers what to do for this issue, and I routinely hear back from them with their successes and failures.
In my experience the layer of sand (or gravel) barrier does not have much effect - the adult gnats can lay their eggs in the drain holes, and at the pot edges. This technique has negative impacts on soil aeration too.
Drier soil can help slow their reproduction, but eventually one does have to water and they re-emerge.
The pot-growing crowd use a treatment where they seal the plant into a bag with a block of dry ice overnight and let the carbon dioxide kill the bugs. This makes some sense, but probably would re-appear right away. It's inexpensive enough that one could repeat the process as needed.
Yellow sticky cards just catch a sampling of the adults, but don't eliminate all the breeding population. The same goes for traps filled with red wine, vinegar, or oil.
There are biological controls if one wants to be organic: one is a nematode, one is a mite, and another is a bacteria (a strain of B.t. israeliensis, or B.t.k.?) mentioned above. These are expensive treatments. Incidentally, the strain that is effective on mosquitoes is not the same one that works on gnats.
With all biological controls, one should not expect complete and permanent solutions.
The new-ish organic product called Spinosad should work too. I have had good results with this, and it does not burn Hoyas.
I use a drench of the "Bayer Advanced Tree and Shrub Insect Control". This is the same compound that is in "Advantage" for dogs and cats; its very safe and has been widely tested in people, mammals, and even reptiles. You put it on the dog's neck and it goes into the body and kills any fleas who bite the dog. When you use the plant version, you drench the soil and gnats go away and don't come back. As a consequence, any insects that eat your plants will be stopped too. Simplest control you can get.
An no, I don't know why gnats like computer screens.
Name: Carol Noel Hawaii (near Hilo) It's all about choices.
Thanks, Dave. The only time I have had gnats in the garden was when I used Neem pellets when I was told they would help against snails/slugs. Results? Did nothing to the s/s and the gnats arrived in full force.
In the kitchen they will be attracted to ANYthing with food on it....
Thanks for all your replies... I watered in some BTK on the plants... seems to have definitely reduced the amount.... they yellow sticky sticks definitely have a big reduction in the amount of flies caught....(even though I hate those yellow things! lol) But I think its working...
I have found that boiling cinnamon and using it as a spray works as well. I boil cinnamon sticks to make a tea like stuff. let it cool off and then spray and store the rest in the fridge. Least it works for me and smells good too.