The Canadian Food Inspection Agency (CFIA) has posted a series of questions and answers to its website regarding the Weed Seeds Order (WSO), 2016. Â The WSO is a ministerial order made under the Seeds Act and plays a critical role in preventing the introduction of new weed species into Canada by preventing or limiting the presence of weed species in seed sold in, or imported into, Canada. Â The new and updated WSO 2016 comes into force November 1, 2016.