Sciarid fly (also known as compost fly) or Fungus Gnats are a common pest of greenhouse plants in the spring.
There are around 600 different species of sciarid within Europe although the species that cause most problems for growers are Bradysia paupera (the Black fungus gnat) and Lycoriella auripila (the Mushroom sciarid).
Young bedding plants, especially bizzie-lizzies, can be affected with large numbers of small flies covering young plants, whilst larvae eat the roots.
The Sciarid flies crawl over the compost surface and if disturbed fly on to the lower leaves. The larval stage in the compost attacks the roots and can kill young seedlings.
Control using nematodes as a drench and then try to keep the surface of the compost as dry as possible (stand trays/ pots in water and soak from the bottom up rather than watering from the top).
Beneficial nematodes are living organisms, so they must be used before the expiry date (which is marked on the inside of the pack and will be around 2-3 weeks) and should be stored in the fridge until it is applied.
To treat Sciarid fly, mix the nematodes with water and water directly into the affected pots / trays.
Each pack of nematodes pack will treat up to 15sqm of compost, for smaller areas just make the solution stronger (you cannot overdose).
- Safe for plants - will not scorch tender seedlings or young plants.
- Safe for you - use on plants in your living room or conservatory.
1. Keep the pack in the fridge and use by the expiry date.
2. Soil should be moist and between 10oC and 30oC during application and 2 weeks after.
3. Avoid applications in direct sunlight; apply on a dull day or in the evening.
4. The pack will treat up to 15sqm of compost. Use all the pack in one go and do not store the solution.
For smaller areas just make the solution stronger (you cannot overdose).
1. Empty tray into a clean bucket and add 1.2 litres (1200ml) of water.
2. Stir thoroughly making sure the entire contents are mixed.
3. Take approx 200ml (1/6th) of this concentrated solution and place in 2gall/10 litre watering can. Fill with water. Using a coarse rose apply to surface of 2.5sqm of compost.
4. Repeat 6 times to cover 15sqm.
5. For smaller areas just make the solution stronger.
6. The nematodes will not harm plant leaves but wash them off into the soil, where they can control the sciarid fly.
If the product is applied over foliage, irrigate immediately to wash nematodes onto substrate.
Treat entire house or plant inventory as soon as pests are seen.
Propagation crops require frequent applications to maintain effective nematode numbers in the soil.
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