Parasitoids of the invasive Nezara viridula (Linnaeus) in Bulgaria

Abstract

The southern green stink bug Nezara viridula (Linnaeus) is a polyphagous species that causes economic damages to many crops in Bulgaria. The aim of this study was to identify the parasitoid species that could suppress the populations of Nezara viridula . A lot of agricultural crops were inspected in the region of Plovdiv, Bulgaria, for the presence of egg parasitoids and imaginal parasitoids of the pest. Egg masses and adults of Nezara viridula were collected during the field surveys in 2019-2021 in Southern Bulgaria. The only parasitoid species emerging from adults of the green stink bug was Trichopoda pennipes (Tachinidae), which is reported for the first time in Bulgaria. The rate of parasitism at field conditions ranged from 2.83% to 35% in the different generations of the host. The egg parasitoids were from family Scelionidae – Trissolcus basalis (Wollaston), Eupelmidae – Anastatus bifasciatus (Geoffroy), and Encyrtidae - Ooencyrtus telenomicida (Vassiliev). It was found that at field conditions the rate of parasitism of the eggs in 2020 and 2021 was respectively 7.77% and 0.25% in May, 34.32% and 17.23% in June, 72.3% and 80.51% in July, and in August – reaching 100% and 89.79%.