Although the various midge species do not themselves cause problems to fish, the presence of large numbers of midge larvae in a pond can cause concern to the pond keeper.
They can be killed very easily by the administration of Lice-Solve™ at the normal dose for other fish parasites. However it is possible to find large quantities of midge larvae in pipework which may not be full of water and of course if the product doesn’t come in contact with the larvae it won’t kill them!
However if there are large numbers of these larvae be aware that the dead biomass could potentially cause a problem in your pond – have a good clean up following treatment! Basic management and hygiene is really important.