Blackflies (biting midges) - how to get rid of them

Fungus gnats are irritating, reproduce rapidly, and in their larval stage, they gnaw on plant roots. They are easily mistaken for fruit flies, at least to an untrained eye, but there are differences. Fruit flies are chubby, brown, and thrive best among fruit and kitchen waste. Fungus gnats are slimmer, have a black head, and can appear in and around potted plants at any time of the year. You can also encounter them outdoors and in greenhouses.Where do fungus gnats come from?It doesn't take much to get fungus gnats in your house. They naturally live in humid areas outside and can easily fly in through open windows and doors. It is also not uncommon to bring fungus gnats inside from plants that have been outside in the summer or from new plants or soil that you bring into your home.Why are there so many fungus gnats?The name fungus gnat is chosen for good reason. Once you have fungus gnats, you quickly get more, and suddenly you have a whole army of gnats flying around your home. But why? Well, each female fungus gnat lays between 40 and 120 eggs during the 5 to 10 days she lives. The norm is close to 100 eggs per fungus gnat. With such reproductive ability, it is no wonder it can feel like an invasion.What damage do fungus gnats do to plants?An adult fungus gnat flying around in its slightly clumsy manner does not cause much damage to plants. It is as a larva that it is most harmful. The fungus gnat lays loads of eggs in the top couple of centimeters of soil. After 4 to 5 days, the eggs hatch and become larvae that live in the soil and eat organic material they find, including plant roots. The larvae can also gnaw on the root collar, leaves lying on the soil, and move up the stem. The fungus gnat remains in the larval stage for 17 to 20 days and then transitions to the pupal stage before, after 3 to 4 days, becoming adult fungus gnats.Well-established plants rarely suffer major damage from a small fungus gnat infestation, but large unaddressed infestations can weaken even larger plants and make them more vulnerable to other types of attacks, such as fungi.Fungus gnats do the most damage to seedlings and cuttings that have not yet properly established themselves. There, the larvae can eat a lot of the roots, and the plants can stop growing or simply die. On cuttings, the larvae can also enter the plant tissue through the wound surfaces.Tips for combating fungus gnatsFungus gnats are not very good flyers and are attracted to the color yellow, water, and light. We can use this to our advantage to get rid of them. A combination of several methods usually works best, so choose some and get started.Set up yellow sticky traps in and around the affected pots. If you leave the light on by the traps at night, you will get maximum effect.A bowl of water can be effective. Choose a yellow bowl if possible. Add a drop of detergent to break the surface tension, so the gnats cannot "walk on water." Some people find that extra gnats go into the water trap if you add a drop of vinegar in addition to the detergent.Use the vacuum cleaner! Tap or shake the pots a little, so the fungus gnats fly up. Since they don't fly very well, it's quite easy to catch many this way.For every fungus gnat you remove, you avoid many tens of new eggs in the pots. But if the infestation is a fact, you also need to combat the eggs, larvae, and pupae to get rid of the invasion.Fungus gnat eggs and larvae tolerate dryness worse than plants, so you can try to dry them out, for example by letting the plants dry completely until they hang their heads and almost wither. The fungus gnats will usually die before the plant does.By removing the top 2-3 cm of soil and replacing it with new soil, you can get rid of many of the eggs.However, the most effective and safest method is to use nature's own means - nematodes. Nematodes are small roundworms that eat up the larvae. At Plantasjen, you can buy Nemablom, which contains such nematodes. These nematodes are insect parasites, completely harmless to both plants, humans, and animals.

Put the crane fly in checkmate with NemablomNemablom is an environmentally friendly and effective pesticide against crane flies. 10 days after treatment, all crane flies should be completely gone.Nemablom contains nematodes of the species Steinernema feltiae, which naturally occur in Swedish soil. The nematodes attack and kill crane fly larvae.Nemablom provides long-term protection, as the nematodes can remain dormant in the soil for up to a year without "food," host organisms.The nematodes only attack larvae – not pupae, eggs, or adult insects, so use it in combination with other measures to combat these.One package of Nemablom is enough for 15-25 pots or approximately 2 m² in a greenhouse.Learn more and buy NemablomSource: BioNema

Tips to prevent infestations of fungus gnats,If you have already experienced an invasion of fungus gnats, you will want to avoid seeing them reproduce quickly in your potted plants again. There are no guarantees against fungus gnats, but good care of the plants, and proper soil, prevent and reduce the chances of the whole army moving into your living room.,Let all plants that can tolerate it dry well between each watering. Fungus gnats prefer to lay their eggs in moist soil. Also, watering only when necessary is the best for the plant.Water from the bottom, so that the top soil stays dry and unwelcoming to fungus gnats. Potted plants will absorb the water they need from the bottom regardless. Make sure to pour out excess water, so there is no stagnant water in pots and saucers.Ensure good drainage. For example, you can add perlite, vermiculite, biochar, or clay pellets to the soil.To make the potted plant less attractive to fungus gnats laying eggs, you can cover the soil with vermiculite or sand.Use well-composted soil for indoor plants. Since fungus gnats feed on uncomposted organic material, the soil is less attractive when it is well composted.,TIPS FROM THE GARDENERMiriam Gysling, gardener and customer service representative at Plantasjen, with a special interest in potted plants in general and cacti and Philodendron specifically.