Bt Cotton Australia Case Study
In 2001/02 Australia grew 404,000 hectares of cotton, with the highest lint yield in the world of 1,658 kg/hectare, for a total production of 670,000 MT; it consumed only 15,000 tons and exported 700,000 tons (ICAC 2002). Cotton production is highly mechanized and intensively managed with irrigation, and inputs including fertilizer and insecticide. The deployment and impact of transgenic Bt cottons in Australia has recently been reviewed comprehensively (Fitt 2002 Personal Communication/In Press) and is the source of information for this case study. All costs are quoted in Australian dollars (A$) where A$1.00 is equivalent to US$0.55.
The two principal insect pests are Australian budworm (Helicoverpa punctigera), and the bollworm, H. armigera; the former causes damage early in the season whereas the latter bollworm causes more damage later in the season. Bollworm has evolved a high degree of resistance to the various classes of insecticides which are employed in an integrated pest management (IPM) strategy. Other insect pests include thrips, mirids, aphids, and spider mites. Pest management accounts for 35 to 40% of operational costs and can range from A$400 (US$220) to A$1,000 (US$550)/hectare.
Bt cotton was field tested and commercially released in 1996/97. The Cry1 Ac gene from Monsanto has been incorporated in CSIRO varieties (INGARD®) and Bt cotton varieties are sold by Cotton Seed Distributors and Delta Pine Land. The area of Bt cotton increased from 30,000 hectares in 1996/97 to 165,000 hectares in regulated annual step increases of 5% up to a maximum of 30% which was reached in 2000/01, and held at that same level in 2001/02 (Table 43 MISSING). The registration of Bt cotton was conditional on the establishment of a resistance management strategy overseen by a committee with representatives from farmers, scientists from the public and private sectors. Resistance management is assigned a very high priority and the limit of 30% Bt cotton is designed to provide the other 70% of cotton as an additional refuge to the required regular refuge; the latter requires 10 hectares of unsprayed cotton per 100 hectares of Bt cotton, or 100 hectares of sprayed conventional cotton, which is the preferred option of farmers. Bt cotton was introduced with a license fee of A$245 (US$135)/hectare which was later reduced to A$155 (US$85)/hectare. Experience with Bt cotton in Australia showed that whereas Bt provides good control of Helicoverpa early in the season, its effectiveness decreases in late season requiring supplementary sprays; the performance of Bt cotton has also been found to vary by location.
The data on yield for Bt cotton and non-Bt cotton in Table 44 MISSING summarizes yield performance over a four year period. There is no significant yield gain or loss from using Bt cotton in Australia. The average yield of Bt cotton over the four year period was 7.8, and 8.0 bales/hectare for non-Bt cotton, respectively.
E. Reduction in Insecticide Use There has been a significant and consistent decrease in the number of sprays required by Bt cotton compared with non-Bt cotton (Table 45 MISSING). The average number of sprays required by Bt cotton (6.5) is 40% less than that required by non-Bt cotton (11.2). The reduction of 4.7 sprays due to Bt cotton assumes high priority in Australia since it is a major contribution to a safer environment and it also provides a foundation on which a more sustainable IPM strategy can be built. In the first two years, insect control costs, which included the technology fee were actually higher for Bt cotton (Table 46 MISSING). However, in 1998/99 and 1999/00 the net benefit was in favor of Bt cotton at A$91 (US$50) and A$72 (US$40)/hectare respectively. The 4.7 spray reduction in Table 45 compares with a reported reduction of 7.7 sprays (Addison 1999).
F. Economic Advantage of Bt Cotton In the initial year, Bt cotton had a significant negative economic benefit of minus $262/hectare due to higher insect control costs, lower yields and exacerbated by a high technology fee of A$245/hectare. When the technology fee was lowered to A$155, this resulted in relatively lower insect control costs for Bt cotton, which translated to a break-even or modest net economic benefits ranging from A$6 (US$3)/hectare in 1998/99 to A$50 (US$28)/hectare in 1999/00. It is noteworthy that the variance associated with net economic benefits is significant; for example, for the average of A$50/hectare in 1999/00 the range was from minus A$1,400/hectare to plus A$2,000/hectare. Despite modest economic returns from Bt cotton, farmers have purchased the full quota of seed available each year because they are convinced of its environmental benefits and that it provides a foundation for a sustainable IPM strategy. The advantages of higher densities of beneficial insects, and the reduced negative effects of broad spectrum insecticides are assigned high ‘economic value’, although they are intangible. In addition, greater farm management flexibility and efficiencies from reduced sprays provide real value to growers not considered in this analysis. The principal ‘economic gain’ of Bt cotton is the fact that farmers are not required to operate an intensive spray control program throughout the season, with its associated negative effects on the implementation of the IPM program.
Prior to the introduction of Bt cotton, Australia concluded that the principal challenge with Bt cotton was the risk associated with the potential development of resistance to the Cry1Ac protein. This has shaped policy in terms of limiting Bt cotton to 30% of the cotton area, rigorous refuge, scouting and monitoring systems to detect resistant insects and a commitment to IPM, in which Bt cotton plays a strategic role. The new double construct Bollgard® II Bt cotton, with the two genes Cry-1-Ac and Cry-2-Ab was approved by the Office of the Gene Technology Regulator for Australia in September 2002. This was the first approval for the product globally, with clearance in the US expected imminently thereafter. It is planned that up to 5,000 hectares of Bollgard® II will be planted in Australia in the 2002/03 season, increasing to 50,000 hectares in 2003/04. Both INGARD® and Bollgard® II will be sold in 2003/04. INGARD® will be withdrawn in 2004/05 and replaced by Bollgard® II. Unlike INGARD®, which was restricted to 30% of the cotton area, the planting area of Bollgard II is not capped and could reach up to 70 or 80% of the crop. Bollgard II is more effective than Bollgard I, and will further reduce insecticide requirements and most importantly provide more durable resistance (Reuters, 2002).
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Case Studies: Related topics:
Summary Report on the Global Status of Commercialized Biotech/GM Crops -[View the 2004 report] Transgenic Crops - [Click Here] Extensive Study on Bt Cotton - [Click Here] Download the complete copy of the ISAAA Briefs on Global Status/Review of GM Crops - [Click Here] SciDev.Net's dossier on GM crops - [Click here] Global Status of Approved Genetically Modified Plants - [Click here] |
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