Meadow midge

The meadow midge (Stenodiplosis geniculati) is a small dipteran insect belonging to the family Cecidomyiidae. It is widely recognized as a significant pest of grass seed crops, where the larvae feed exclusively on the floral organs of various perennial grasses.

This pest primarily attacks species such as meadow foxtail, timothy grass, fescue, and orchard grass. By consuming the developing ovaries within the florets, the larvae prevent seed formation, leading to substantial reductions in seed yield for agricultural producers.

The biological cycle is closely synchronized with the flowering phenology of host plants. Adults emerge in spring when grass heads begin to emerge from the sheath. Females lay eggs inside the glumes, and the emerging larvae feed throughout the seed maturation period, eventually overwintering in the soil or within the plant debris.

The damage caused by Stenodiplosis geniculati is often overlooked until harvest, as external symptoms may be subtle. However, infected heads produce sterile florets, and a close inspection of the spikelets reveals small, bright orange larvae that indicate a severe infestation that significantly impacts the crop's economic value.

To control the population of this midge, agronomists recommend:

• Implementing strict crop rotation to break the pest's life cycle.
• Ploughing down infested stubble shortly after harvest to bury overwintering larvae.
• Maintaining field isolation by keeping new seed crops away from old grass pastures.
• Applying targeted insecticides during the adult flight peak if monitoring indicates high population density.