A weed resistant to a widely used chemical to protect crops has spread for the first time to Western Canada, the country’s grain and canola belt. Kochia weed turned up in three fields in Southern Alberta last August, despite the use of glyphosate, and Canadian government scientists have now confirmed that it is resistant to the farm chemical, seed company Monsanto Canada said on Wednesday. [...] The southern Alberta case is unique because it does not appear to have developed in a field where farmers regularly grew Roundup Ready crops