According to Ian Heap, a weed specialist, who completed his PhD on resistance to multiple herbicides in annual ryegrass ("Lolium rigidum") in 1988 – the first case of an herbicide-resistant weed in Australia – by 2014 "Lolium rigidum" was the "world’s worst herbicide-resistant weed" with instances in "12 countries, 11 sites of action, 9 cropping regimens" and affecting "over 2 million hectares." Annual ryegrass has been known to be resistant to herbicides since 1982. The first documented case of glyphosate-resistant "L. rigidum" was reported in Australia in 1996 near Orange, New South Wales. In 2006, farmers associations were reporting 107 biotypes of weeds within 63 weed species with herbicide resistance. In 2009, Canada identified its first resistant weed, giant ragweed, and at that time 15 weed species had been confirmed as resistant to glyphosate. As of 2010, in the United States of soil were afflicted by herbicide-resistant weeds, or about 5% of the 170 million acres planted with corn, soybeans, and cotton, the crops most affected, in 22 states. In 2012, Charles Benbrook reported that the Weed Science Society of America listed 22 herbicide-resistant species in the U.S., with over infested by GR weeds and that Dow AgroSciences had carried out a survey and reported a figure of around . The International Survey of Herbicide Resistant Weeds database lists species that are resistant to glyphosate.