Two methods for estimating the tolerance of common bean genotypesto Empoasca kraemeri Ross & Moore were compared, using ayield trial carried out at Centro Internacional de Agricultura Tropical(CIAT), Cali, Colombia, versus stylet penetration tactics measured byAC electronic feeding monitors. A stylet penetration index was devisedbased on principal component scores of three penetration tacticsidentified (pulsing laceration, cell rupturing, and lancing sapingestion), combined with knowledge of the hopperburn symptoms causedby each tactic. Tolerant genotypes, as classified by the CIAT yieldindex, showed significantly more unprotected yield and lower hopperburnscores than the susceptible control. They also induced performance ofless pulsing laceration (the tactic considered most damaging to theplant), and more of the other two, mitigating tactics, especially cellrupturing. When index values were calculated for each genotype, styletpenetration index values matched those of the yield index for three outof five genotypes: two EMP-coded tolerant lines (‘EMP 385’ and ‘EMP392’) and the susceptible control ‘BAT 41’. Thus, for these threegenotypes, all subsequent hopperburn symptoms are predictable by thetype of feeding behavior performed on them. ‘PorrilloSintético’ and ‘EMP 84’, considered borderline genotypes bythe yield index, were overestimated and underestimated, respectively,by the stylet penetration index. We postulate that, for these twogenotypes, plant physiological responses to feeding (eithercompensatory or heightened sensitivity, respectively) synergize withtype of feeding performed to generate the overall hopperburn condition.This multivariate analysis of electronic monitoring data wassuccessfully used to devise an index of resistance. The implications ofusing the stylet penetration index and the advantages of usingelectronic monitoring in a bean-breeding program are discussed.