GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - A5O56SMDVURJ813TJ

Each of the following, if true, could provide a logical explanation for why farmers in large areas of the midwestern United States do not rotate their corn crops EXCEPT: A. The cost of rotating corn with soybeans is greater than the cost of accepting lower yields of corn as a result of damage inflicted by the northern corn rootworm. B. A safe and effective combination of insecticides has been found to be more effective at eradicating northern corn rootworm than has crop rotation. C. The capacity of the northern corn rootworm to synchronize its diapause with farmers rotation schedule has made this method of control significantly less effective. D. The price that the farmers can get for soybeans and other crops that could be effectively rotated with corn has dropped significantly. E. Farmers have yet to discover a variety of corn that can effectively resist northern corn rootworm.