An Encounter with Dark-Winged Fungus Gnats (SCIARIDAE)

 

Fungus gnats are DIPTERANS associated with fungi in moist soil and decaying plants

These are very small flies at just 1cm long

A large hump appears on the portion between the head and the base of the wings

Sciaridae wings have two branched sclerotized wing veins 

They have long legs, with enlarged coxa and femur segments

The smoke to dark colored wings of Sciarids

Fungus gnats favor excess moisture on potting medium of indoor plants

The green and living landscape trend has taken both the residential and office spaces by storm! Live plants, contained in pots of various forms and sizes filled with a concoction of soil, potting media and other organic materials are now a major component of the indoor landscape. 

A number of these insects are emerging from the pots and plants are becoming a nuisance. They get into people's faces and contaminate food and drinks. 

What are these very small, mosquito-like, dark-colored insects emerging from our indoor plant havens? These are what we call the fungus gnats!

For this article we will focus on one family of fungus gnats, the SCIARIDAE (Dark-Winged Fungus Gnats). 

The adult dark-winged fungus gnats are 1-11mm long, with a slender body, mosquito-like, with long legs, black to dark brown colored body and smoke-colored wings. There legs have distinctly enlarged coxa (1st) and femur (2nd) segments. They have long, segmented antennae.  

The larvae appear slightly longer than the adult gnats with a shiny black head and a 12-segmented white translucent body.

Females can lay up to 200 eggs on MOIST organic materials in the soil surface. Total developmental time (egg to adult) takes 10-14 days. The adults are short-lived, after mating and egg-laying they die within 5 days. 

The adults are typically found on or near the larvae food materials. The larvae feed primarily on fungi growing in the soil, decaying organic matter, animal excrement and on rotting wood. Indoors, the infestations of fungus gnats are mainly associated with the soil of overwatered potted plants and atriums. Water leaks or moisture issues which support fungal growth can also support larval development. During the day, the adults congregate on dark moist areas. Adults are attracted to light.

There are 1700 recorded species of SCIARIDAE occupying diverse moist, organic material rich habitats worldwide.    

In low numbers, they are mainly a nuisance. But if their indoor population explodes, high numbers on indoor pots and atriums can lead to larvae damaging the plant roots resulting in stunting of growth. The high number on plant seedling can result to damping off and death of the seedlings. Some Sciarid species are also reported as pests of greenhouses and mushroom-growing houses.

IPM CONTROL TIPS

1. Conduct careful inspection and identification.

2. Identify the breeding source(s). Look for the moist/damp areas that support fungal growth. Search for overwatered pots, moist potting medium, water leaks on walls and void areas.

3. Systematically address and remove all potential moisture and damp conditions. Drying out or the removal of moist materials will prevent fungal growth. 

4. Avoid overwatering of plants. Remember that it is the moist soil surface that attracts the females to lay their eggs.  

5. Strategically install sticky card traps near your pots assembly. Fungus gnats are highly attracted to these yellow-colored sticky traps. Install and replace the traps regularly. 

6. Fly paper traps also capture the adults and help reduced the numbers on indoor plant sections.

7. The fungus gnat adults are highly attracted to light. Installation and servicing of UV light traps can help in reducing indoor fungus gnat numbers.

8. If the numbers are high and insecticide application is required, make sure to use non phytotoxic products for spraying or ULV-misting treatment. Always read and follow label instructions. (Pesticide application should be conducted by trained, approved and licensed Pest Management Professionals ONLY) 

 These dark-winged fungus gnats might be very small but indoors they will truly capture your attention, especially when they emerge from your favorite potted plants!

I had an awesome time doing the microscopic analysis of these small flies! 

Awesome creature! Awesome CREATOR!