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About the Authors:
Yunhe Li
Affiliations Department of Entomology, Cornell University/NYSAES, Geneva, New York, United States of America, State Key Laboratory of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China
Jörg Romeis
Affiliation: Agroscope Reckenholz-Tänikon Research Station ART, Zurich, Switzerland
Ping Wang
Affiliation: Department of Entomology, Cornell University/NYSAES, Geneva, New York, United States of America
Yufa Peng
Affiliation: State Key Laboratory of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Science, Beijing, China
Anthony M. Shelton
* E-mail: [email protected]
Affiliation: Department of Entomology, Cornell University/NYSAES, Geneva, New York, United States of America
Introduction
Cotton is one of the most important economic crops worldwide. In 2006, it was grown in >75 countries with a total production of 27 billion kilograms, and supplied almost 40% of the global demand for fiber [1], [2]. However, many species of insect pests attack cotton plants, and the resulting damage can cause enormous yield losses. Therefore, a substantial part of the cotton production budget is allocated to controlling insect pests. Before the use of insect-resistant genetically engineered (IRGE) cotton, the cotton crop accounted for an estimated 22.5% of the total insecticide used worldwide [1], [2]. Commercial transgenic cotton, expressing one or two Cry toxins derived from the soil bacterium Bacillus thuringiensis (Bt), has been shown to be effective against many lepidopteran pests including Heliothis virescens (Fabricius), Helicoverpa armigera (Hübner), Helicoverpa zea (Boddie), Pectinophora gossypiella (Saunders) and Trichoplusia ni (Hübner) in the field and laboratory [3]–[6]. Because of the effectiveness of Bt cotton and the resulting significant reduction in the use of broader spectrum insecticides [7], the area grown to Bt cotton has increased rapidly around the world [8].
Like any technology there have been questions about the potential risks Bt cotton may have on the environment [9]. One of the major ecological concerns regarding the environmental impact of Bt plants is their potential effects on non-target organisms since they provide important ecosystem services such as biological control (predators and parasitoids) [10]–[13].
The ladybird beetle Coleomegilla maculata (DeGeer) is a common and abundant predator found in many cropping systems worldwide [14]. Both larvae and adults of C. maculata are predaceous, feeding on aphids, thrips, and lepidopteran eggs and young...