OTTAWA — The federal government’s plan to ban some single-use plastic products by labelling them “toxic” to the environment is defamatory and harmful to the companies that produce them, an industry group said Wednesday. Environment Minister Jonathan Wilkinson announced a list of six single-use plastic items that will be banned because they are both harmful to the environment and difficult to recycle. Plastic straws, stir sticks, cutlery, six-pack rings, carry-out bags and Styrofoam plates and takeout containers won’t be allowed to be sold in Canada once the ban takes effect, likely by the end of 2021. Other single-use items will be managed by setting standards to encourage them to be reused or recycled.