A news item in yesterday's Times Online ("Tate & Lyle under attack from Paraguay and India") reports that a herb used by the Guarani tribe of Paraguay has wiped 7p off the value of shares in Tate & Lyle, which fell to 445¼p. The share drop is a response to the news that US-based Wisdom Natural Brands is ready to distribute its SweetLeaf sweetener based on the stevia leaf to table-tops across America, cutting into already weak sales of Tate’s Splenda sweetener. The market potential of stevia has been noted in Paraguay, where the National Agronomy Institute has developed a new variety, 'ireté', which contains twice the amount of the sweetener compound in the same quantity of leaves.