Bt cotton varieties have expanded their demand in Ascención, Chihuahua, Mexico since 1998. This was due to the presence of insect pests such as the complex tobacco bud/bollworm and pink bollworm. Cotton growers planted 14,265 ha total (249 ha of Bt cotton) in 1998, 8,994 ha total (1,626 ha of Bt cotton) in 1999, 8,789 ha total (2,391 ha of Bt cotton) in 2000, and 8,938 ha total (6,703 ha of Bt cotton) in 2001.