Soybean stem fly

The soybean stem fly (Melanagromyza sojae) belongs to the order Diptera and the family Agromyzidae. It is recognized as a significant pest of legumes, particularly soybean crops, and is prevalent in many regions across Asia and other parts of the world where soybeans are grown intensively.

The primary host plant is soybean (Glycine max). However, the pest is known to infest a variety of other legumes, including kidney beans and various wild leguminous weeds, which serve as alternative hosts during off-season periods or when soybean is not available.

The life cycle consists of egg, larval, pupal, and adult stages. The adult female flies lay eggs in the leaf tissues, typically near the midrib or petiole. Upon hatching, the larvae tunnel into the stem, where they feed on the inner tissues and complete their development, often pupating within the stem tunnels.

Damage is primarily caused by the larvae as they tunnel through the plant tissues. This mining activity disrupts the transport of water and nutrients, leading to stunted plant growth, wilting, leaf yellowing, and occasionally death of the entire plant. Heavy infestations can significantly reduce the final seed yield.

• Crop rotation to break the pest's life cycle.
• Removal of host weeds surrounding the fields.
• Seed treatment with systemic insecticides before planting.
• Foliar application of insecticides based on adult monitoring data.
• Utilization of resistant or tolerant soybean varieties.