Natural parasitism of maize stemborers, Sesamia spp. (Lepidoptera: Noctuidae) eggs by Trichogramma evanescens (Hymenoptera: Trichogrammatidae) in Southeastern Turkey

Abstract

Maize, Zea mays L., is currently among the leading cultivated crops in Turkey. Several lepidopteran stemborer species especially, Sesamia nonagrioides Lefèbvre and S. cretica Lederer (Lepidoptera: Noctuidae) may cause high maize yield losses. This study is the first to report parasitism of Sesamia spp. eggs by Trichogramma evanescens (Hymenoptera: Trichogrammatidae) in Southeastern Turkey. During our extensive 3-years region-wide survey program (2018-2020), we collected Sesamia spp. eggs laid between leaf sheets and cobs/stalks. T. evanescens adults hatched from the host eggs collected from two locations in Diyarbakır: one in the central county (L10) and the other in Bismil county (L11). The discovery efficiency, parasitism efficiency, and parasitoid impact indexes of T. evanescens were 77.5%, 38.92%, and 32.87% in L10 and 50.0%, 33.45%, and 12.42% for L11, respectively. Sesamia spp. eggs collected from other counties of Diyarbakır province and other provinces such as Batman, Mardin, and Şanlıurfa did not yield in T. evanescens emergence. To our best knowledge, this study is the first to report the presence of T. evanescens in Southeastern Turkey. Possible factors involved in the restriction of T. evanescens are discussed. Special attention should be devoted to increase the potential of conservative biological control strategies to support egg parasitoids.