Host plant resistance

Definition

The heritable capacity of a plant genotype to reduce herbivore damage, infestation, or fitness below the level sustained by susceptible genotypes of the same species. In entomological contexts, host plant resistance operates through three principal mechanisms: antibiosis (adverse effects on insect survival, development, or reproduction), antixenosis (deterrence of oviposition or feeding through non-preference), and tolerance (ability to withstand damage while maintaining yield or fitness). These mechanisms may involve constitutive defenses such as trichomes, lignin, or allelochemicals, or induced defenses triggered by herbivore damage or oviposition cues.

Etymology

Example

Cultivated maize varieties expressing the gene Vip3A produce vegetative insecticidal proteins that confer host plant resistance against lepidopteran larvae such as fall armyworm (Spodoptera frugiperda), reducing leaf damage and ear penetration compared to susceptible hybrids.

Synonyms

• plant resistance to insects
• host resistance

Related Terms

• Antibiosis
• antixenosis
• Tolerance
• induced defense
• constitutive defense
• gall midge biotype
• gene-for-gene resistance
• horizontal resistance
• vertical resistance
• secondary metabolite

Usage Notes

Distinguish from general 'plant defense,' which encompasses all protective traits regardless of genetic variation among host genotypes. Host plant resistance is a population-level concept requiring measurable variation between resistant and susceptible plant lines. In applied entomology, the term often implies heritable traits usable in breeding programs; induced resistance triggered by prior damage is sometimes treated separately unless the induction capacity itself varies genetically. Mechanisms are not mutually exclusive—a single resistant cultivar may combine antixenosis (repelling aphid alatae) with antibiosis (reducing nymphal survival).