A comparison of resistance mechanisms in common beans, Phaseolus vulgaris, to Empoasca fabae and Empoasca kraemeri
Empoasca fabae' is the most abundant insect pest of ' Phaseolus vulgaris' in Ontario. Controlled greenhouse experiments and naturally infested field experiments were conducted at Centro Internacional de Agricultura Tropical, Colombia and Ridgetown, Ontario, Canada to determine whether 'Phaseolus vulgaris' lines exhibiting resistance to 'Empoasca kraemeri' of S. America also exhibited resistance to the N. American 'E. fabae'. Antixenotic effects among bean genotypes were detected for both species under free-choice greenhouse infestations, but not in no-choice experiments. In the field, EMP lines were consistently less preferred by 'E. fabae'. Under field infestations of 'E. kraemeri', unprotected seed yields were higher for EMP genotypes than Ontario bean genotypes. Under ' E. fabae' attack there was no significant difference for yield between insecticide protected and unprotected plots, nor was there any difference among the genotypes under either insecticide treatment. Hopperburn scores of the genotypes were positively correlated between the insects.