Field studies showed thatEdovum puttleriGrissell, an egg parasitoid of the Colorado potato beetle,Leptinotarsa decemlineata(Say), did not visit and feed on nectar of flowers commonly found near potato fields in the northeastern United States. Field cage observations and laboratory tests determined thatE. puttleriuses aphid honeydew on potato as a source of nutrition. Because aphids do not usually colonize potato crops until early July in the Northeast, honeydew scarcity may prevent early-season establishment of this parasitoid in potato.