This study describes the influence of tomato,Lycopersicon esculentumMill, and bean plant,Phaseolus vulgarisL., intercropping on the potato leafhopper,Empoasca fabae(Harris). The field design consisted of a single density of snap bean plants intercropped with a gradient of tomato plant densities. Leafhopper oviposition, nymph and natural enemy populations, and plant growth were monitored throughout two seasons. A complementary laboratory study analyzed the potential influence of host plant quality upon its acceptability for oviposition by potato leafhopper. Leafhopper densities in medium to high density intercrop subplots were>25% of those populations on bean planted alone, during periods of high leafhopper population densities. Differences in nymphal counts between treatments were a function of oviposition, not differential nymphal mortality from natural enemies or host plant resistance. Differences in tomato plant density across treatments did not fully account for differences in leafhopper densities. Reduced bean host plant acceptability was observed when choice tests were conducted using beans grown under different fertilizer levels. Up to 76% of the eggs were laid in plants containing the greatest amount of total nitrogen. Although tomato is believed to have directly reduced leafhopper densities in the intercrop treatments, the additional effect of host plant quality was also shown to be a potentially important factor.