Canadians need to seriously discuss new technology for fighting insect pests using genetic modification, scientists say.
Their concerns are expressed in a new report from the Pest Management Review Agency, a branch of Health Canada that regulates the use of pesticides.
Experts say genetic modification could provide a powerful new tool as old insecticides lose effectiveness and climate change leads to new infestations.
Such techniques are already being used in trials to stop mosquitoes from spreading malaria.
The report’s authors caution that there are many unknown variables. They argue that the consequences of releasing synthetic versions of natural organisms could be harmful and permanent.
New hope
The genetics of insect pests are being turned against themselves by scientists, who are modifying the genomes of their familiar enemies in ways that give farmers and doctors new ways to combat them.
This booming field offers new hope against old scourges such as malaria. And it could provide brilliant new tools as familiar insecticides lose effectiveness and climate change reshuffles the cards.
But concerns buzz around the new technology like a swarm of gnats.
“Questions remain about the effectiveness of these tools, their safety and their relevance,” indicates a new report from the Council of Canadian Academies. Is it appropriate to deploy gene editing in the natural environment and how will gene editing fit into the broader pest control toolbox? »
The report, released last week, was commissioned by the Pest Management Regulatory Agency, a branch of Health Canada that regulates chemicals used to control pests. It’s the start of what its authors hope will be an urgent and thoughtful debate about the possible role of an entirely new way of eliminating these insects.
“Genetic pest control tools could radically alter our relationship with the environment, not only because of their potential impact on the ecosystem of which we are a part, but also because of their challenge to the social and cultural values that shape decisions surrounding their use,” we can read there.
Resistance and climate change
Genetic pest control is being considered for several reasons, said co-author Mark Belmonte, a University of Manitoba biologist.
“Traditional pesticides are becoming less effective, either because insects are developing resistance or because communities are looking for what I consider to be safer alternatives,” he explains.
Climate change adds its own pressures.
“We have very cold winters and it’s great for insect control,” Belmonte said. Now we’re seeing a huge change where cold spells don’t last as long or disappear altogether. We find that insect populations change quite quickly. »
Additionally, this technique reduces the use of chemicals and, unlike pesticides, it strongly targets a single species.
Several strategies
Genetic responses to these challenges can either modify a genome to sterilize the pest, or modify something else that makes it less effective, for example by reducing its ability to survive cold.
These two strategies can be used in two ways.
In one, a modified population of sterile males is introduced in numbers large enough to reduce and control an infestation. Modified insects should be periodically reintroduced.
In the other, the insect – perhaps with a change making it vulnerable to a chemical – is modified in such a way that its genome replaces the original in the overall population. The new arrival becomes the new norm.
Humans have been modifying animals through selective breeding for centuries. But it seems new, said co-author Ben Matthews, a zoologist at the University of Manitoba.
“We are doing something fundamentally different,” he believes.
Breeding animals for desired traits provides years to evaluate their behavior and impacts. This is not the case with an organism that has been modified in a laboratory and released, Mr. Matthews said.
Many are uncomfortable with the idea of “playing God,” he added.
Genetically modified mosquitoes are already being tested in Africa against malaria, a disease that killed nearly 620,000 people last year. This finding makes a compelling case for continued research, said Robert Slater, professor of public policy at Carleton University and chair of the committee that wrote the report.
Little evidence
Canada is just beginning to discuss how to regulate genetically modified insects, Slater said. This isn’t going to be easy.
“The regulatory system operates on the basis of evidence. He has to weigh what are the risks and what are the benefits. This is a brand new technology and we have very little evidence,” he said.
Mr. Slater said he and his colleagues recommended a slow approach, with lots of what he called “exit ramps.”
Small field trials would allow regulators to learn how to work with local communities and provide much-needed data on effects and benefits. More research is needed – as well as other, often sparse, areas.
“Anyone who gets involved in this science has to have one characteristic,” Slater said. Humility. »