Assessment of the Potential Efficiency of Parasitism in Two Competitive Scelionid Parasites of Nezara viridula L. : (Hemiptera : Pentatomidae)

Abstract

In order to assess the parastic effeiciencies of two egg parasites, Asolcus mitsukurii ASHMEAD and Telenomus nakagawai WATANABE, which compete with each other for the egg of Nezara viridula, a large number of hosts were artificially placed in the fields and exposed to parasites for a short period, i.e. one week. The host finding ability of T. nakagawai was superior to that of A. mitsukurii and the period of residence on the egg mass was shorter in the former than in the latter. The percentage parasitism of egg masses invreased more rapidly in T. nakagawai than A. mitsukurii with an increase in their densities. T. nakagawai was able to parasitize the egg masses more efficiently than A. mitsukurii during the limited exposure of the egg mases. These facts show that T. nakagawai would be more promising egg parasite, if there were no competition with A. mitsukurii.