The Western University biology professor and his team have used a genome they created last year to identify how two-spotted spider mites – super-destructive in agriculture – develop resistance to pesticides.
They’ve also come up with a way to establish which pesticides the microscopic mites will adapt to.
The plant-feeding mites feast on a wide range of crops, including tomatoes, peppers, strawberries, soya-beans and apples.
“Thank goodness, I’ve never had them,” crop farmer Bill Fry said of the mites. “They just suck the juice out of the plants and kill it.”
The mite is well known in the agriculture industry for its ability to resist traditional chemical controls.
In Southwestern Ontario, one of the nation’s largest farm belts, a spider mite outbreak can mean huge financial losses.
“They were a big problem in the area a few years ago,” said Craig MacNeil an employee of the pesticide company UAP. “Whenever it’s really droughty and the crops are under stress, spider mites seem to . . . affect the crop worse.”
Agriculture and Agri-Food Canada says spider mite infestations come in waves in Southwestern Ontario, but given the region’s climate, the critters are much more of a problem indoors. In a region that has some of Canada’s largest concentrations of greenhouses, that’s a significant threat.
“Our idea was to pick an organism which has economic importance and the spider (mite) is one of the biggest pests in the world,” said Grbic. “It’s present on pretty much every continent, it’s feeding on over 150 crop plants and it’s a real nightmare for pest control.”
Because spider mites can develop resistances to pesticides within two to four years, farmers spraying the same repellent year after year create a situation in which there is no solution, said Grbic.
Using their genome, or genetic map, the research team developed a method to tackle that issue in target areas by using appropriate pesticides.
It means the resear chers can take a sample of a spider mite and in the laboratory check whether it will build resistance to pesticides, said Grbic.
Such a process takes three to four days to complete and screens the mites against up to 380 potential resistances.
The researchers also hope to develop a kit in the next year that could yield similar results in real time.
Long-term, Grbic and his team hope to alter the actual biological construct of crops to shut down spider mites that feed on such plants.
The discoveries have been financed by several grants since 2006, including from the U.S. Department of Energy, a joint Genome Canada-European Union initiative and the province.
Written by Eric Clement. Published in The London Free Press, March 10, 2012.