Fungus gnats are often a problem in which environments?

• A. Potted plants
• B. Outdoor fields
• C. Indoor plants
• D. Greenhouses

Answer: (C)

Fungus gnats are most problematic around damp, organic-rich soil used for indoor plants. Their eggs hatch in moist potting mix, and the larvae feed on fungi and decaying organic matter in that soil, so the warm, shaded, consistently moist conditions found indoors create ideal breeding grounds. Outdoor fields tend to dry out more and don’t provide the same stable moisture, making fungus gnats less of an issue there. Greenhouses can also have problems when humidity and frequent watering keep the soil consistently moist, but the typical classroom or exam scenario emphasizes indoor houseplants as the common setting.