The above-mentioned plan – which may be cited as the “Ontario Tomato Seedling Growers’ Marketing Plan” applies to the control and regulation in any or all respects of the marketing within Ontario of tomato seedlings including the cases in which prohibition of such production and marketing obtains. There shall be a local board to be known as the “Ontario Tomato Seedling Growers’ Marketing Board being composed of not more than 5 members.