[Objectives]  To compare the population growth of Bemisia tabaci (Gennadius) on different pepper varieties by establishing the correlation between the content of the leaves of each variety and the population size of B. tabaci. [Methods]  The population trend index (I) of whiteflies feeding on different varieties of peppers was calculated, and the quantity of soluble sugar, soluble protein, free proline, phenolic compounds and flavonoids, in pepper leaves, measured. The correlation between whitefly population size and leaf content was analyzed. [Results]  There were significant differences in the size of whitefly populations that fed on different varieties of peppers. Insect-resistant varieties had significantly higher amounts of soluble sugar, phenolic compounds and flavonoids, but lower soluble protein and free proline, than susceptible varieties. I was significantly, negatively correlated with soluble sugar, phenolic compounds and flavonoids, and significantly, positively correlated with soluble protein and free proline. Among the factors measured, soluble sugar had the most important effect on I. Multiple regression analysis was used to model the relationship between I and five factors; soluble sugar (X₁), soluble protein (X₂), free proline (X₃), phenolic compounds (X₄) and flavonoids (X₅). The regression equation was: Y = 47.801– 1.754X₁+1.206 X₂+1.108 X₃ –0.437 X₄ –0.649 X₅ (R² = 0.688). [Conclusion]  Insect-resistant pepper varieties had significantly lower whitefly populations than susceptible varieties.