Dark-winged fungus gnat

Systematic position. The dark-winged fungus gnat (Bradysia coprophila) belongs to the order Diptera and the family Sciaridae. These small flies are notorious pests in greenhouse environments, plant nurseries, and indoor gardens, thriving in habitats with high moisture and organic decomposition.

Host plants. This pest affects a wide range of horticultural crops, including ornamental flowers like poinsettias and cyclamens, as well as young vegetable seedlings. It is particularly devastating for crops started from seed in peat-based potting mixes.

Biology and life cycle. The life cycle consists of the egg, larval, pupal, and adult stages. The adult gnats are short-lived and primarily focus on reproduction, depositing eggs into moist soil. The larvae, which are the primary damaging stage, feed on organic matter, fungi, and the roots of living plants, progressing through several larval instars within the soil medium.

Damage and harmfulness. Larval feeding on root hairs and primary root tissue leads to stunted growth, wilting, and poor plant vigor. In severe infestations, the damage to the root system facilitates the entry of soil-borne pathogens, often leading to rapid collapse and death of susceptible seedlings.

Control measures. Integrated pest management (IPM) is essential for effective control of Bradysia coprophila.

• Monitor adult populations using yellow sticky traps.
• Practice cultural control by avoiding overwatering and allowing the soil surface to dry out.
• Use biological control agents such as predatory mites or beneficial nematodes (e.g., Steinernema feltiae).
• Apply soil-applied insecticides or biological larvicides (Bacillus thuringiensis israelensis) when populations exceed thresholds.