Fungus gnats
Insect
- Presence of a few flies at soil level
- Presence of numerous flies at soil level
| Difficulty Low |
| Frquency Very high |
| Reproductive rate Up to 300x |
| Lifecycle Up to 20 days |
Fungus gnats, also known as soil flies or shore flies, are small dark brown flies that feed on decaying matter in moist soil. They can indirectly damage plants.
Host plants
Soil of any type of plant and region can be infested with fungus gnats. Greenhouse conditions are particularly favorable to them, and the rich soil of tropical plants may be more conducive.
Screening
Adult fungus gnats are easily visible as they fly near the soil. They do not intentionally attack plants, and their presence is not necessarily harmful. However, when present in large numbers, they can damage certain secondary roots and contribute to the transmission of plant pathogens. Therefore, their presence should be minimally controlled, especially in horticultural production contexts.
Prevention
Excessively moist or frequently watered soils provide a conducive environment for fungus gnat proliferation. Regular introductions of Stratiolaelaps scimitus help control the larval population in the soil.
Treatment
Fungus gnat infestation is relatively easy to treat. Yellow sticky traps are a good way to control the adult population, and nematodes are very effective against the larvae. Combining with Stratiolaelaps scimitus, which establish long-term in the soil, is the most effective and prevents reinfestation.
Products
Morphology
Adults measure three to five millimeters in length. Larvae measure between two and three millimeters and feed at soil level. They are white, translucent, and their head is black.
Behaviour
Adult fungus gnats feed on liquids. A limited presence of larvae in the soil can have a beneficial effect on plants as they feed on decomposing organic matter, produce certain minerals, and contribute to soil aeration.
Lifecycle
The fungus gnat life cycle consists of four stages: egg, larva, pupa, and adult. Eggs laid in moist soil hatch in about three days. The complete life cycle lasts less than 20 days, as adults die shortly after reproduction.