Economics of host-plant resistance.

Abstract Host-plant resistance (HPR) has been declared the foundation of integrated pest management (IPM), which is compatible with all strategies and integrated tactics. However, there is bias in publications about HPR. Most published studies highlight positive results with research and development. Very few crop varieties reach field trials unless they show harvestable yields similar to those of older varieties. And then the value of a variety, that may yield more under high pest pressure because of resistance to pests, still must be shown to be economical in most situations faced by farmers. Otherwise, farmers will prefer higher yields in most years with older crop varieties with protection provided by some other IPM tactic in the years with high pest pressure. Thus, a survey of publications will likely not cover the costs of failures and limited successes, leading to biased views in favour of HPR. This chapter shows that most of the published cases support the view that resistance by crops against insects is valuable over decades, not just single growing seasons. When the costs of HPR research and development have been estimated, the benefits exceed the costs over 10-20 years. These results should encourage others to continue the research and to take the extra steps to demonstrate the benefits to farmers and society.