Sterile mosquitoes cut tiger mosquito numbers in Graz by up to 70%

A programme to control tiger mosquitoes in Graz is showing results, with the population in two test areas reduced by up to 70%, ORF reported. Around two million sterile male tiger mosquitoes are due to be released this year.

Erwin Wieser of the Graz health department leads the project. His team visits areas where residents report tiger mosquitoes through the Mosquito Alert app, by phone or by email. They inspect gardens, identify breeding sites and speak to property owners.

Tiger mosquitoes typically fly only about 100 to 150 metres, Wieser said, making cooperation across neighbouring properties important.

“We urgently need more cooperation from the public,” he said. “We ring the doorbell and sometimes people say, ‘Leave us alone, we don’t have tiger mosquitoes or a tiger mosquito problem.’ But we know there are problems, because if they are in one garden, they are also in the next.”

The health department is urging residents to look for and remove breeding sites in their gardens. Saucers under flower pots containing water are ideal breeding sites for tiger mosquitoes.

“Where people are active and remove the breeding sites, there are fewer mosquitoes,” Wieser said. “Releasing sterile mosquitoes alone is not enough. It is just one part of the solution. If mosquitoes continue breeding in the background, it is like pouring a bucket of water into the Mur. It achieves nothing.”

The tiger mosquito can no longer be completely eradicated, according to the report. This year, the project will monitor the Liebenau district to determine how many sterile mosquitoes should be released there next year.