A British company that has developed a genetically modified mosquito to resist the spread of dengue fever is coming up against growing opposition to a plan to release the insects into the Florida Keys.

A Change.org petition started by a woman in Key West opposing the release has garnered almost 90,000 signatures and rising. "Say no to genetically modified mosquitoes release," the petition demands.

Mila de Mier, the author of the petition, began the campaign because she said she was worried about the lack of scientific understanding of what the insects could do to the delicate ecosystem of the Florida Keys. She accused Oxitec, the UK-based biotech firm that has developed the mosquito, of failing to listen to local wishes.

"We need more data. If something goes wrong the consequences could be catastrophic not only for humans but also the whole ecosystem, and I don't want my family being used as laboratory rats for this," de Mier told the Guardian.

Oxitec, whose headquarters are in Abingdon, Oxfordshire, has developed the genetically modified mosquito in laboratories over the past 10 years, releasing it into the open in the Cayman islands for the first time in 2009. The insect belongs to the Aedes aegypti species which is the carrier of dengue fever.

Hadyn Parry, Oxitec's chief executive, said that that the company had been approached by officials in Florida after dengue fever was reported in the Keys in 2009 and 2010. "The decision to go ahead is entirely a local Floridal decision – it's not up to us," he said.

The petition calls on the federal regulator the US Food and Drug Administration to withhold permission for Oxitec's mosquito to be released. De Mier said there are too many questions left hanging, such as whether the gene introduced into the insect could itself mutate, or whether the reduction of the A. aegypti mosquito could have adverse connotations for the local ecosystem.

Parry dismissed those fears. Only male mosquitoes would be released, he said, that do not bite and do not carry dengue fever.

The mutation works by effectively sterelising the mosquitoes and preventing them from having offspring. That also means, Oxitec insists, that there is no danger of the mutation that has been introduced to the males from being passed down the generations.

"This is a form of birth control for mosquitoes. It brings the population of the species down very fast indeed," Parry said.

The tests in the Cayman islands suggested that the number of A. aegypti mosquitoes could be reduced by about 75% over a year. It had no impact on any other species of mosquito or other insect types, and allowed the amount of chemical pesticide sprayed locally also to be reduced, the company says.

Dengue fever has become a growing problem around the world, as the carrier mosquito spreads in warming climates. It strikes about 100 million people a year globally with a flu-like illness that can be severe and even fatal.

It is now found everywhere north of Buenos Aires and south of Miami, as well as in 27 other southerly states in the US.

In the Keys, the virus that causes dengue has to be brought in every year and is then carried from person to person by the mosquitoes. As there is so much international tourism to the area, the chance of incoming viruses are high and although there were no incidents in 2011, there is a chance of repeat outbreaks.