Nepali scientists are using insects to control the rampant growth of water hyacinth at Begnas and Phewa lakes in Kaski. The exotic water plant, locally known as Jalkumbhi, has been taking over large sections of rivers and lakes across the country.
Nepal Agriculture Research Council (NARC) in coordination with an American research institution introduced over 500 locally available beetle (Neochetina eichhorniae) to control the water hyacinth in the two lakes two months ago.
“We are experimenting with the biological control method using insects which are specific natural enemies to water hyacinth or destructive weeds in Phewa and Begnas,” said Yagya Raj Giri, principal scientist and chief at the NARC’s Entomology Division.
His team had conducted a pilot survey on the use of insect to control the growth of destructive aquatic weeds in Chitwan for almost two years before introducing it in Pokhara. According to Giri, a certain population of the insect has spread over in open areas in the lakes where they act as a control agent and feast on the invasive plant.
Similar biological way of controlling the growth of water hyacinth and hydrilla-like plants is on practice in the United States, Latin American countries and some parts of South Africa, Giri said.
He said two different weevil species have been introduced in Florida in the US to control the growth of aquatic weeds. “We were planning to bring the insect species from US earlier but later found a native species that could work as control agent on water hyacinth,” he said, adding, “The species from the US will be brought within February and we will test both of these insects to find the suitable species to give needed results.”
According to researchers working on this experiment, it will take time to see the impact on use of insects to control the encroachment of lakes by water hyacinth. They hope to control the invasive plant by almost 60 percent.
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