Context: 

An exotic beetle released into a vast reservoir in Betul district (Madhya Pradesh) has successfully eradicated an invasive weed species, Salvinia molesta, within 18 months.

Background:

Cyrtobagus salvinia, the exotic beetle , was imported to India after thorough research and with the necessary governmental approvals. Within 15 to 18 months, its population multiplied significantly, effectively consuming and destroying the weed.

SALVINIA MOLESTA :

1. Salvinia molesta, commonly known as giant salvinia, or as kariba weed after it infested a large portion of Lake Kariba between Zimbabwe and Zambia, is an aquatic fern, native to south-eastern Brazil.
2. It is a free-floating plant that does not attach to the soil, but instead remains buoyant on the surface of a body of water.
3. It thrives in slow-moving, nutrient-rich, warm, freshwater. A rapidly growing competitive plant, it is dispersed long distances within a waterbody (via water currents) and between waterbodies (via animals and contaminated equipment, boats or vehicles).
4. Salvinia molesta may form dense vegetation mats that reduce water-flow and lower the light and oxygen levels in the water. This stagnant dark environment negatively affects the biodiversity and abundance of freshwater species, including fish and submerged aquatic plants.
5. Salvinia molesta can alter wetland ecosystems and cause wetland loss and also poses a severe threat to socio-economic activities dependent on open, flowing and/or high quality waterbodies.
6. It is on the list of the World’s 100 Most Invasive Species.