In the Lensli Academy we regularly inform you about practical situations that we encounter in the sector, we talk about insights gained in practice, we give you cultivation tips and we share our knowledge about other interesting substrate-related matters.
Academy – Sciara
What is Sciara?
Sciara is a small black-grey fly of 2 to 3 mm long that is also called the fern fungus gnat. In practice, we often encounter Scaria in places where cultivation takes place on substrate. The larvae of this insect can cause various problems.
When the Sciara pressure is high in a crop, damage is often seen to young soft plant parts, such as the root tips and the transition from root to plant. The feeding of the Scaria larvae can cause growth disorders of the crop. Damaged plant parts can then become a gateway for various plant pathogenic fungi, such as Pythium. The larvae and sciarid flies can also transfer fungal spores to healthy plants.
The life cycle of Sciara is partly dependent on temperature. Under favourable conditions, the development from egg to fly takes three weeks. The mosquito itself lives only a few days to a week, but can lay 150 eggs in this short time(!). These eggs are deposited in the substrate.
The larvae are easy to recognize by a translucent white body and a black head. The larvae do not grow larger than 8mm and have no legs. In the greenhouse and in substrate the conditions are often so favorable that after a week a mosquito flies out again.
Experience shows that Scaria develops ideally under warm, dark, humid conditions.
Some substrates and packaging forms are more susceptible to Sciara than others. Our experience is that the mosquito develops more easily when the above conditions are combined with raw materials of young organic origin.
A big bag seems to be more easily contaminated from the outside than, for example, a big bale. This can be partly prevented by ordering a cover from us to pull over the big bag. Sciara is often present in the greenhouse, but also outside. You often find them in places where a lot of algae grows or on rotting plant remains.
In substrates where, due to circumstances during cultivation, a lot of algae growth occurs, we often see many insects such as sciara, shore flies, fruit flies and Coenosia species.
Preventing high Sciara pressure in substrate cultivation
Fortunately, there is enough to do to make the living conditions less attractive for this insect. Think of:
- Better drying of the top layer of substrate (substrate adjustment, better air movement, different watering)
- Hygiene environment (puddle formation, removal of plant remains, algae and weeds and the method of storage of the substrate)
- Cover with insect screen
- UV Lamps
Sciara can be controlled well with biological agents such as nematodes, predatory mites, beetles and sticky traps. It is advisable to discuss this with your crop protection specialist if the pressure becomes too high. Especially if biological agents are combined with possible chemical corrective agents.
For more information read the factsheet of the RHP.
Do you have questions or would you like to know more about this subject? Please contact your Lensli account manager or our Substrates Technical Product Manager Nick Vollmer by email n.vollmer@lensli.com or telephone +31 (6) 51269415.