The Evolution of Cotton Pest Management Practices in China

Abstract

The development of cotton pest management practices in China has followed a pattern seen for many crops that rely heavily on insecticides. Helicoverpa armigera resistance to chemical pesticides resulted in the unprecedented pest densities of the early 1990s. Transgenic cotton that expresses a gene derived from the bacterium Bacillus thuringiensis (Bt) has been deployed for combating H. armigera since 1997. The pest management tactics associated with Bt cotton have resulted in a drastic reduction in insecticide use, which usually results in a significant increase in populations of beneficial insects and thus contributes to the improvement of the natural control of some pests. Risk assessment analyses show that the natural refuges derived from the mixed-planting system of cotton, corn, soybean, and peanut on small-scale, single-family-owned farms play an important function in delaying evolution of cotton bollworm resistance, and that no trend toward Bt cotton resistance has been apparent despite intensive planting of Bt cotton over the past several years.

Temporal allocation of metabolic tolerance to transgenic Bt cotton in beet armyworm, Spodoptera exigua (Hübner)

“…In China, planting of Bt cotton has grown from 6.3×10 4 hm 2 in 1998 to 3.5×10 6 hm 2 in 2006, which is equivalent to approximately 60% of the total cotton area in this country [3,25]. Transgenic Bt cotton is considerably effective in controlling lepidopteran pests, and is highly beneficial to growers and the environment by reducing chemical insecticide sprays and preserving populations of beneficial arthropods [26,27]. Currently, there are many publications that have focused on the development and reproduction of herbivorous insects in response to B. thuringiensis.…”

“…Insect resistance or tolerance problems is another issue that should be viewed as a part of integrated management strategies including IPM and integrated resistance management (IRM) programs [27]. Since the first commercial release of GM crops expressing Bt genes, there have been environmental impact concerns.…”

Ecological Impacts of Genetically Modified Crops: Ten Years of Field Research and Commercial Cultivation

“…Direct environmental benefits of reduced insecticide applications in Bt-cotton resulted in fewer non-target effects [55,56] and in reduced pesticide inputs Ecological Impacts of Genetically Modified Crops 269 in water [159]. In China, for example, the number of pesticide applications against lepidopteran pests in cotton has considerably dropped from nine in 1994 to four applications in 2001 following the adoption of Bt-cotton [162]. Concerns have been raised that these environmental benefits may be lowered by additional spraying against secondary pests that were formerly controlled by the broad spectrum pesticides.…”

Adoption of Bt Cotton: Threats and Challenges

“…Growing Bt cotton has become a key measure to effectively control damage caused by the cotton bollworm Pectinophora gossypiella and H. armigera Li et al, 2006). With the commercial cultivation of Bt cotton, the infestation of both pink and cotton bollworms tends to gradually decrease, while the risk of severe damage in certain regions significantly diminishes (Wu and Guo, 2005). Decreasing insecticide application in Bt cotton fields increased the diversity of beneficial natural enemies such as ladybugs Chrysopa spp., while spiders effectively controlled the development of harmful insect populations in cotton .…”