Reductions in insecticide use from adoption of Bt cotton in South Africa: impacts on economic performance and toxic load to the environment

Abstract

The study reported presents the findings relating to commercial growing of genetically-modified Bt cotton in South Africa by a large sample of smallholder farmers over three seasons (1998/99, 1999/2000, 2000/01) following adoption. The analysis presents constructs and compares groupwise differences for key variables in Bt v. non-Bt technology and uses regressions to further analyse the production and profit impacts of Bt adoption. Analysis of the distribution of benefits between farmers due to the technology is also presented. In parallel with these socio-economic measures, the toxic loads being presented to the environment following the introduction of Bt cotton are monitored in terms of insecticide active ingredient (ai) and the Biocide Index. The latter adjusts ai to allow for differing persistence and toxicity of insecticides.Results show substantial and significant financial benefits to smallholder cotton growers of adopting Bt cotton over three seasons in terms of increased yields, lower insecticide spray costs and higher gross margins. This includes one particularly wet, poor growing season. In addition, those with the smaller holdings appeared to benefit proportionately more from the technology (in terms of higher gross margins) than those with larger holdings. Analysis using the Gini-coefficient suggests that the Bt technology has helped to reduce inequality amongst smallholder cotton growers in Makhathini compared to what may have been the position if they had grown conventional cotton. However, while Bt growers applied lower amounts of insecticide and had lower Biocide Indices (per ha) than growers of non-Bt cotton, some of this advantage was due to a reduction in non-bollworm insecticide. Indeed, the Biocide Index for all farmers in the population actually increased with the introduction of Bt cotton.The results indicate the complexity of such studies on the socio-economic and environmental impacts of GM varieties in the developing world.

Social Impacts of GM Crops in Agriculture: A Systematic Literature Review

“…These studies reported that farmers in Australia, India and China experience reduced health problems as a result of declining pesticide use with Bt cotton and rice [80,[83][84][85]. In contrast, studies by Bennett et al [86] and Debyani and Neeta [87] from South Africa and India reported negative health implications for farmers as a result of adoption of Bt cotton, due to increased toxic exposure and allergic reactions, respectively. Both these studies made the connection between their data and wellbeing, without measuring wellbeing impacts directly.…”

“…Both these studies made the connection between their data and wellbeing, without measuring wellbeing impacts directly. Bennett et al [86] connected pesticide exposure to health effects without measuring health effects as such, and Debyani and Neeta [87] reported that farmers have claimed allergic reactions, without independently testing whether such reactions are connected with exposure to Bt cotton. The three remaining bottom-up studies did not connect wellbeing effects with empirical observations at farm or household level.…”

“…Higher yields and/or reduced pesticide use can then have secondary social impacts such as improved household finances, better labour conditions and health improvements. Looking specifically at studies of Bt cotton relying on own farm-level data, there were 23 such studies in the dataset [53,66,67,70,76,77,[81][82][83][84][85][86][87][93][94][95][96][97][98][99][100][101][102]. The majority (12) were from India, followed by South Africa (5), Argentina (2), Burkina Faso (2), Mexico (1) and Australia (1) as the only country representing the Global North.…”

Effects of training, innovation and new technology on African smallholder farmers’ economic outcomes and food security

“…Famous examples of interventions promoting new technologies and innovations in Africa include the provision of genetically improved crops, such as the new Bt cotton variety (Bennett et al 2004).…”

Preliminary development of a genetic strategy to prevent transgene escape by blocking effective pollen flow from transgenic plants

“…While advances in biotechnology have continued at a rapid pace, field trials for more than 4000 GM plants have so far resulted in the successful release of only 40 transgenic crops for commercial purposes (Daniell 1999;Brookes and Barfoot 2005). Benefits derived from these GM crops include reduced environment impact due to a decrease in the use of toxic herbicides and insecticides (Bennett et al 2004). Other potential and demonstrated benefits include an increase in productivity, salt/drought tolerance, and disease resistance.…”