Lesser dung fly

Lesser dung flies (the genus Borborus, belonging to the family Sphaeroceridae) are small flies that are generally considered secondary pests in agriculture. These insects belong to the order Diptera. Their presence in agro-ecosystems is usually associated with decaying organic matter, but under certain environmental conditions, they can infest weakened plant tissues, causing significant physiological damage.

These flies primarily attack vegetable seedlings and various crops grown in greenhouses where humidity levels remain high. The larvae typically focus on the roots and the lower part of the stem, facilitating the development of secondary bacterial and fungal infections. Both larvae and adults contribute to the spread of pathogens, making them a dual threat to crop health.

The biological development of the pest depends heavily on moisture and decomposing organic material. The life cycle comprises the egg stage, three larval instars, a pupal stage, and the adult fly. Under favorable conditions with high humidity, a single generation can complete its development in approximately three to four weeks, allowing for multiple generations to occur during a single growing season.

Damage symptoms usually manifest as the softening of stems at the soil line and the rapid wilting of plants. The economic impact is primarily seen in seedling mortality and the reduced vigor of adult plants. Because the larvae thrive in organic-rich media, the presence of decaying plant debris in the root zone acts as a primary attractant and breeding ground for the population.

Integrated pest management strategies are recommended to control these flies:

• Managing greenhouse ventilation to maintain optimal humidity levels.
• Strict sanitation protocols, including the removal of all decaying plant debris.
• Use of sterilized growing media and substrates to prevent initial infestation.
• Application of specific soil-applied insecticides if the pest population reaches damaging levels.