Small Black flies : -(

[Im not hungry]

Hello Everyone

This is my second year growing (containers & V small Green house) and I joined this great forum last year, so hello again and hi to the new members

Any way I was hoping that someone could shed some light on my current problem?

My plant in the green house (GH) are all ok but I have an infestation of very small black flies. They seem to sit in the top of plant pots and I only notice them when I water the plants and then loads of flies take off. On close inspection thay seem to be happy just sitting in the soil doing nothing, but I would much rather they were not there!

I did think is trying to take a picture of the issue although I'm not David Bailey! ( they are black and very small)

Anyone got an idea to to what they are and how to get rid of them?

Kind Regards to all

Paul

[DavidT]

They are Sciarid flies Paul. Very difficult to get rid of, making sure the compost is kept moist seems to help. You could try using a pesticide suitable for edible plants, but to my mind they are a nuisance more than anything.

[stupo74]

Hi All,
Found this, hope it helps,,

Sciarid flies, also known as fungus gnats, can be serious pests of herbs. The larvae damage the roots of young plants, leading to poor vigour, wilting and even death. Adult sciarid flies can also carry important fungal pathogens e.g. Pythium. Sciarids are often present as secondary pests on plants affected by root disease, the larvae feeding on the rotting plant tissue and fungi. The presence of the flies on plants at marketing can cause crop rejections by supermarkets

Symptoms
Young seedlings and cuttings are very susceptible to damage by the larvae, which weaken growth and can cause plant death. Sciarid larvae can tunnel up the stems of young cuttings. Plants with well-established roots are less susceptible to damage, but heavy infestations can cause plant wilting and death. Larvae can also feed on the lower leaves resting on the compost (Fig. 4), and this damage can be confused with that made by slugs.


Sources of infestation and favourable conditions
Sciarid flies can occur all year round on protected herbs, especially in warm, moist conditions e.g. in propagation houses. However, they are more of a problem in spring and summer, when warm temperatures allow faster increase in numbers, especially when more frequent watering is needed, which favours development of the pest. The development time from egg to adult is around three weeks at 21-23°C, but this will be faster at higher temperatures. The adults, although weak fliers, can fly from infested areas to newly emerged seedlings or young cuttings.

cheers stupo