Adult Sciarid Flies live on and around the compost surface of pots and trays, most of the damage is caused by their young.
Most common indoors posing a problem all year round, due to the damage their larvae cause they are a real problem at this time of year when there's lots of tender new seedlings, cuttings and new growth. They are pretty easy to spot, brownish in colour & 3-4mm long they crawl and slowly fly around pots and trays generally being a nuisance. In their larval stage they are slim white maggots that can be up to 6mm long.
Sciarid Fly thrive in warm moist conditions and are a particular problem where greenhouse hygiene may have been overlooked. Water at the beginning of the day and try to avoid excessive wetness at the end of the day and always sweep up excess compost and plant debris, ensuring the growing bench is as clean as possible all of the time.
We have 3 different controls that are useful for controlling Sciarid Fly, firstly to help you identify an infestation and to trap some of the adults there's yellow sticky traps. You can use these all year round but they are particularly useful around your seedling trays to trap Sciarid Fly adults. They are also really good value so worth putting up even just as a preventative measure. To control the larvae and therefore stop the damage we supply two different solutions, which one you choose will be down to how bad your infestation is but also your growing conditions.
Soil temperature of at least 10°? Bad infestation?
We sell beneficial nematodes which are watered on and attack the sciarid fly larvae underground. They are not a proactive predator, they need to be introduced close their food and will die out if they do not have anything to feed on which is why we only recommend them if you know you have a bad infestation. Nematodes also need moist compost so don't work so well in small spaces or plants grown in bark etc.
Soil temperature of at least 12°? Infestation not too bad?
Hypoaspis mites are a great solution, they are hard working, crawling over the compost to find their prey. They are fine in dryer conditions don't need lots of compost to live in. They can work well as a preventative measure to stop new outbreaks as they have a reputation of living for quite a long time without food (when they have been previously fed). Maybe even giving you protection for a few months.