Host Plant Resistance: Is It Time for a New Model?

Host plant resistance (HPR) is a fundamental control tactic in integrated pest management programs. The evaluation of plant varieties for the expression of resistance against major insect pests is a key step for recommending and deploying resistant varieties in crops where pest pressure is high. Therefore, the use and publicizing of appropriate terminologies on HPR have a pivotal role in conveying information on effective resistant varieties to the scientific community and farmers. Basically, there are two HPR terminologies being used in the Entomology scientific literature: the classical HPR definition based on the trichotomous model of resistance, i.e., antixenosis, antibiosis, and tolerance; and a more recent proposition dividing plant defense into resistance vs. tolerance, the sichotomous model, which also incorporates the concepts of constitutive vs. induced resistance and direct vs. indirect resistance. In addition, there is scarce information on insect-resistance levels in commercial plant varieties to be divulged in seed labels, with exception of the Bt transgenic varieties. Using unstandardized technical terms on HPR can be confusing and less likely to transmit proper information on resistant varieties, hindering their use in the field. This review discusses the terminologies on HPR, the research gaps, and proposes a concept of what should be considered a resistant variety for practical purposes and uses by farmers, extension services, and the scientific public. Finally, the proposed HPR defense-growth model is presented for appreciation.