fungus gnat larvae

having a real problem with these on my young greenhouse plants in work at the moment. :( any suggestions would be welcome.

I have provado ultimate bug killer and provado vine weevil killer, both thiacloprid and I get the impression from the interweb that its not very good for these critters. Anyone got any experience with this? I don't like to use them unless I'm sure they will be effective. I don't think my boss will spring for any different treatments as times are hard....

also, I used nematode vine weevil control about 6 weeks ago. I guess its safe to use a systemic by now but its pointless using the organic version and then having to resort to chems anyway for a different problem. How frustrating!!

I do try to control the watering but things take so long to dry out at this time of year.....

 

How about a top dressing of sharp sand?
Or do you have far too many pots to make this practical?

 

Hi Pete,

I have been thinking about that after googling and seeing that suggestion on the web - there are quite a few pots but there is not much else to do in the GH at this time of year.

My only reluctance is because it will make it more difficult to know when things need water and make the actual watering more difficult with sand washing all over the place. Thats if i've got any sand left...

it does look as if it is the best non money spending, non chemical option....

thanks

Emily

 

When I have problems with fungus gnats in my houseplants I use a squirt of washing up liquid in the watering can and spray around the plants with some mixed in a spray bottle as well to get the adults. Always works well for me, is cheap, and safe.

 

Something I have done myself, I think if you mix in say 25% sharp sand with the potting compost you are less likely to get the problem.
Maybe something to try with overwintering pots as its not really a summer problem.

 

Thanks Pete and Catztail,

managed to beg some sharp sand from some contractors on site and have started to top dress the worst affected pots with it.

Will try the washing up liquid option if that doesn't work - does it actually work on the grubs as well as the adults?

Emily

 

I find it does. I think it suffocates the dirty boogers.

 

thanks catztail annd good night