From Invasive Weed to Complete Suppression: ICAR-DWR’s Biological Control Success at Tal Morbe

An extensive infestation of the invasive aquatic weed Salvinia molesta across approximately 14 acres of a water body at Tal Morbe, Karjat, Maharashtra, was successfully brought under control through a targeted biological management programme by ICAR–Directorate of Weed Research, Jabalpur.

The dense infestation had adversely affected the aquatic ecosystem and limited the productive use of the water body. Recognising the limitations of conventional manual and mechanical removal, ICAR-DWR adopted a sustainable biological control approach using the highly specific weevil Cyrtobagous salviniae.

On 11 February 2025, approximately 30,000 C. salviniae were released into the infested water body. The weevils established and multiplied naturally, progressively damaging the growing points, rhizomes and other actively growing parts of S. molesta.

ICAR-DWR undertook regular monitoring to assess the establishment and effectiveness of the biocontrol agent. A substantial decline in the infestation was observed over the following months, with extensive deterioration of the weed by May 2026. The biological control process continued progressively, culminating in the complete suppression and management of S. molesta by July 2026.

The successful management of the 14-acre infestation demonstrates the potential of targeted biological control as a sustainable approach for managing invasive aquatic weeds and restoring the productive use of infested water bodies.

Approximately 14 acres of Salvinia molesta infestation at Tal Morbe, Karjat, was successfully managed through biological control using Cyrtobagous salviniae.

(Source: ICAR–Directorate of Weed Research, Jabalpur)