Current Use of Bt Overseas
Genetically modified Bt crops
Countries that have had commercial releases of plants modified to produce Bt toxins include Australia, Canada, China, India, Mexico, South Africa, Spain, and the USA.
In the USA, the Environmental Protection Agency estimates that Bt field corn was grown on 0.4 million acres (1 percent) in 1996, 4.4 million acres (6 percent) in 1997, 14.5 million acres (18 percent) in 1998, 19.8 million acres (26 percent) in 1999 and 19.5 million acres (25 percent) in 2000. For Bt cotton, the total planted was 1.8 million acres in 1996, 2.6 million acres in 1997, 2.5 million acres in 1998, 3.6 million acres in 1999, and 4.4 million acres in 2000. For Bt potatoes, data indicate that 50,000 acres of Bt potatoes were planted in 1998 and 1999, and about 5000 acres were planted in 2000 (USEPA, 2001). In addition to commercial plantings, some 18 other Bt crop species including apples, broccoli, rice, tomato and walnut have been approved for field testing (Mellon and Rissler, 1998).
In Australia, it was estimated that around 30 percent of the cotton grown in the 1999-2000 season had been modified to express a Bt toxin. In September 2002, a new variety of Bt cotton was approved for commercial release south of 22 degrees South. The new variety, called Bollgard II expresses two different Bt proteins and is therefore "expected to be less susceptible to insect predation and less likely to promote the development of resistance".
Non-genetically modified Bt sprays
Pesticide sprays containing Bt are used worldwide, but only represent a small proportion of the overall global market for pesticides. There is evidence that resistance to Bt sprays can arise with overuse in the field and Bt sprays have recently been subject to resistance management programmes (e.g. Walker et al. 1999).
In the early 1990s, the global market for Bt-based bioinsecticide was estimated to be in the range of 100 million US dollars. In 2000, the global insecticide market was estimated at 8 billion US dollars and there was considered to be a strong indication that biological pesticides accounted for some 500 million US dollars (Joung and Côté, 2000). Again, market opportunities for Bt may be arising as consumers seek alternatives to products that have been sprayed with conventional chemical insecticides.
Bt-based sprays are used to control pests on a number of crops in the USA. The National Pesticide Use Database (1997) recorded that Bt-based sprays were used on 12 percent of apples grown, 56 percent of cabbage, 43 percent of lettuce, and 28 percent of strawberries. Bt-based sprays were used on less than 1 percent of cotton, corn and soybeans being grown.
Contact for Enquiries
Dr Sharon Adamson
Manager,
Innovation Policy
Ministry of Agriculture and Forestry
PO Box 2526
Wellington
NEW ZEALAND
Phone: +64 4 894 0618
Fax: +64 4 4 894 0741
Contact this person
