SOCIOECONOMIC AND FARM-LEVEL EFFECTS OF GENETICALLY MODIFIED CROPS 33


production levels have decreased drastically and remain limited mainly due to the relatively low price of cotton.


Bt Maize


Globally, in 2007 GM maize was planted on 35 million hectares, or 24 percent of world maize plantings, of which 9.3 million hectares was Bt as single trait and another 18.8 million hectares in combination with other traits (James 2007). In 2010 GM maize covered 46.8 million hectares globally, and the area increased to 51 million hectares in 2011 (James 2010, 2011). Bt maize was first introduced in the United States in 1996, and by 2006 it covered 40 per- cent or 12.7 million hectares of the total US maize crop. In Argentina, vari eties containing the Bt trait were planted on 73 percent of the total Argentinean maize area, and in Spain it covered 54,000 hectares or 15 percent of the total maize area (Brookes and Barfoot 2008). Maize is the most important field crop in South Africa and annually cov-


ers an estimated 30 percent of the total arable land. Maize serves as staple food for the majority of the South African population and also as the main feedgrain for livestock. Between 60 and 70 percent of the South African yel- low maize production is consumed in the chicken-production sector. Over the past 9–10 years, South Africa produced an average of 9.3 million metric tons of maize on 2.75 million hectares. Even though Bt yellow maize was released in 1998 for commercial pro-


duction, GM white maize was commercialized only in 2001. That year, South Africa became the first country in the world to permit the commercial produc- tion of a GM subsistence crop—Bt white maize. In South Africa and other southern African countries, the losses sustained in maize crops due to damage caused by the African maize stem (stalk) borer (Busseola fusca) are estimated to be between 5 and 75 percent, and it is generally accepted that, pre-Bt, Busseola annually reduced the South African maize crop by an average of 10 percent (Annecke and Moran 1982). Gouse et al. (2005) showed that in 2005 with a seemingly conservative estimate of 10 percent for damage caused by both Busseola fusca and Chilo partellus, the average annual loss (in the absence of Bt) adds up to just under a million tons of maize, with an approximate value of ZAR810 million. At the 2008 maize price level (more or less similar to the 2011 price level), the potential damage caused by borers would be closer to ZAR1.6 billion (about $200 million). Both B. fusca and C. partellus can be controlled to a satisfactory level with the use of the Bt gene currently used in South African Bt varieties (Cry1Ac).


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