Can you bring aerosol bug spray for ants from Portugal to Canada in your checked luggage?
You should check your airline's rules to know for certain, but for instance, TAP Portugal says:
The transport by air of dangerous articles is not permitted, such as: [...] Toxic – (insecticides or pesticides);
I strongly suspect that other airlines will be similar.
Anyway, such products should be readily available in Canada, so it would likely be much easier to buy it after you arrive.