The persistence and distribution ofEdovum puttleriGrissell, an egg parasitoid of Colorado potato beetle,Leptinotarsa decemlineata(Say), on potato (Solanum tuberosumL.) plants with different host resources were quantified.E. puttleriwere released into 1.5-m3field cages enclosing pairs of potato plants with different combinations of host eggs, aphids producing honeydew, or without these resources. Observations every 2 h throughout the day revealed that the parasitoids spent more time during peak foraging periods on plants with aphids or host eggs, or both. However, the percentage of parasitism and mortality of beetle egg masses was not significantly higher on plants with aphids. The relationship between parasitism and mortality of beetle eggs byE. puttleriand weather conditions were analyzed.