China was the first developing country to introduce Bt cotton on a large scale. This paper provides an indepth economic analysis of Bt cotton production by small-scale farmers in China. Data were collected in 2002 in Linqing County, in Shandong Province and comprised a season-long cotton production monitoring with 150 farmers and complementary household interviews. For quality assessment, the Bt toxin concentration of the various Bt varieties used by the farmers was determined for each plot. All farmers were growing insect resistant Bt cotton varieties. Yet, they sprayed high amounts of chemical insecticides, out of which 40% were extremely or highly hazardous. The paper reviews methodological issues inherent to impact assessment of crop biotechnology and identifies market and institutional failure as possible reasons for continued high pesticide use. Using the damage function methodology the coefficients for both damage control inputs, i.e., Bt varieties (measured as toxin concentration), and insecticide...

Why Do Some Bt-Cotton Farmers in China Continue to Use High Levels of Pesticides?

▪ Abstract We used the California Pesticide Use Reports to study use of fungicides, bactericides, fumigants, and selected insecticides, primarily for vegetable, fruit, and nut production in California from 1993 to 2000. There were no obvious trends in decreased use of most compounds used to treat plant disease. However, growers have rapidly adopted recently introduced “conventional” compounds. There is very limited use of microbial biocontrol agents to control plant disease and no indication of an increase. We used case studies to explore the potential of different strategies to reduce pesticide use or risk. There have been reductions in use of organophosphate insecticides, largely by substitution with pyrethroids. Theoretically, replacement of “calendar spray” pesticide programs with “environmentally driven” programs could reduce pesticide use in years with lower disease pressure, but this assumes that the majority of growers currently use a “calendar spray” program and that growers who use less than rec...

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Patterns of pesticide use in california and the implications for strategies for reduction of pesticides

SUMMARY Evidence for the role of chitinases, proteases and beta-1,3- and beta-1,6-glucanases in mycoparasitism by Trichoderma species has been well documented. Moreover, constitutive over-expression of genes encoding individual cell-wall-degrading enzymes (CWDEs) has been shown to improve the potential of biological agents. In this study, we generated transformants of T. virens in which beta-1,3- and beta-1,6-glucanase genes, TvBgn2 and TvBgn3, respectively, were constitutively coexpressed in the same genetic T. virens Gv29.8 wild-type background. The double over-expression transformants (dOEs) grow and sporulate slower than the wild-type (WT). However, the reduction in growth did not seem to affect their mycoparasitic and biocontrol capabilities, as dOEs displayed much higher levels of total beta-1,3- and beta-1,6-glucanase activity than the WT. This higher enzymatic activity of dOEs positively correlated with observed in vitro inhibition of Pythium ultimum and Rhizoctonia solani mycelia, and with enhanced bioprotection of cotton seedlings against P. ultimum, R. solani and Rhizopus oryzae. Besides effective biocontrol of all pathogens at an original inoculum level, the performance of dOEs was highly enhanced (up to 312% of WT performance) when pathogen pressure was greater (i.e. concentration of inoculum was higher or pathogens applied in combination). These results demonstrate that the strategy of introducing multiple lytic enzyme-encoding genes through transformation of a given biocontrol strain can be successfully used to achieve better biocontrol.

https://bsppjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1364-3703.2007.00407.x

Enhanced biocontrol activity of Trichoderma virens transformants constitutively coexpressing β‐1,3‐ and β‐1,6‐glucanase genes

The three northern hemisphere anguillid eel species experienced recruitment declines at similar times beginning in the 1970s and 1980s, but the exact causes of the declines have remainedunclear. Attention focusedon two categories of possible causes that included (i) anthropogenic impacts on eel growth habitats, such as dam construction, degradation and pollution of habitats, introduction of parasites, overfishing and (ii) changes in ocean-atmospheric conditions affecting their marine life-history stages. The cumulative effects of reaching peaks in dam construction, levels of pollution, and eutrophication just before the eel declines likely had reduced eel production in many areas, and contamination by metallic and organic compounds and parasites may have reduced reproductive success. Shifts in ocean-atmospheric conditions also occurred just before the eel declines that could have reduced feeding success of larvae or disrupted larval transport. If oceanic regime shifts reduced production of the marine snow food of eel larvae, it may have affected larval survival and recruitment success, especially if there is a critical time-window for successful larval first feeding when marine snow particles need to be abundant. A reduction of these particles could result in density-dependent earlymortality of the larvae of each spawning event, and competition formarine snowparticleswith sympatrically spawningmesopelagic eel larvae would amplify this effect. Nutrient reductions causing shifts in the relative abundance of phytoplankton contributing tomarine snow production and of ubiquitous cyanobacteriamaymediate levels of larval survival in areaswith high spawning activity. Reductions of eels reaching the spawning area fromspecies rangemargins that spawnoutsideof peak spawningperiods couldhave reduced recruitment further. It appears likely that avariety of impacts, oceanic and anthropogenic occurred simultaneously causing sudden declines of these eel populations.

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Did a “perfect storm” of oceanic changes and continental anthropogenic impacts cause northern hemisphere anguillid recruitment reductions?

Cotton with coevolving pests has been grown in India more than 5000 years. Hybrid cotton was introduced in the 1970s with increases in fertilizer and in insecticide use against pink bollworm that caused outbreaks of bollworm. Hybrid Bt cotton, introduced in 2002 to control bollworm and other lepidopteran pests, is grown on more than 90 % of the cotton area. Despite initial declines, year 2013 insecticide use is at 2000 levels, yields plateaued nationally, and farmer suicides increased in some areas. Biological modeling of the pre-1970s cotton/pink bollworm system was used to examine the need for Bt cotton, conditions for its economic viability, and linkage to farmer suicides. Yields in rainfed cotton depend on timing, distribution, and quantity of monsoon rains. Pink bollworm causes damage in irrigated cotton, but not in rainfed cotton unless infested from irrigated fields. Use of Bt cotton seed and insecticide in rainfed cotton is questionable. Bt cotton may be economic in irrigated cotton, whereas costs of Bt seed and insecticide increase the risk of farmer bankruptcy in low-yield rainfed cotton. Inability to use saved seed and inadequate agronomic information trap cotton farmers on biotechnology and insecticide treadmills. Annual suicide rates in rainfed areas are inversely related to farm size and yield, and directly related to increases in Bt cotton adoption (i.e., costs). High-density short-season cottons could increase yields and reduce input costs in irrigated and rainfed cotton. Policy makers need holistic analysis before new technologies are implemented in agricultural development.

/pdf/deconstructing-indian-cotton-weather-yields-and-suicides-4ljpftaynh.pdf

Deconstructing Indian cotton: weather, yields, and suicides

Two technologies of crop protection are compared, crop protection by pesticides and by Genetically Modified Plants (GMPs). The history of pesticides provides lessons relevant to the future of GMPs; (1) high pesticide usage is counter-productive, (2) the technology requires intensive regulation and (3) has nonetheless many external effects which strongly reduce its social benefits, (4) early calculations on net benefits of pesticides were over-optimistic, and (5) intensive use of pesticides made farmers so dependent on them that they lost important options. These lessons are used to construct a framework for the economic analysis of GMPs which can be applied once sufficient empirical information becomes available. Conceptually the framework can be used for a comparison of crop protection strategies indicated as chemical crop protection, threshold-based crop protection, crop protection by ecotechnology and organic agriculture. Given the current state of knowledge on the impact of GMPs where (1) benefits are assumed rather than proven, (2) regulatory costs are rising and (3) environmental and human health risks have yet to be fully identified, one conclusion is that ex ante economic analysis which draws upon some of the lessons learned with chemical pesticides may help to bridge the gap between the proponents and the opponents of GMT (Genetic Modification Technology).

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H. Waibel

Papers

From pesticides to genetically modified plants: history, economics and politics