Determination of the efficacy of some entomopathogenic nematodes on Spodoptera littoralis (Boisduval, 1833) (Lepidoptera: Noctuidae) in laboratory conditions

Abstract

Spodoptera littoralis (Boisduval, 1833) (Lepidoptera: Noctuidae) is a polyfag pest causing losses all over the world. Entomopathogenic nematodes (EPN) have a regulatory role on insect populations in the soil ecosystem. The aim of this study was to determine the effects of commercial biopreparations of some EPNs on fifth instar larvae of S. littoralis at different doses and days. Biopreparations containing Heterorhabditis bacteriophora (Poinar, 1975) (Rhabditida: Heterorhabditidae), Steinernema carpocapsae (Weiser, 1955) and Steinernema feltiae (Filipjev, 1934) (Rhabditida: Steinernematidae) were used in the study. These biopreparations were adjusted at doses of 50, 100, 200 and 400 IJs/5ml of tap water and applied to 50 g of sterilized sandy soil in a plastic container, and one individual of S. littoralis larvae was released on it. The study was conducted in 2022 at 27±2°C under laboratory conditions for 5 days. According to the results of the study, the highest average mortality rates were 100 and 95% in the S. carpocapsae preparation application at 400 and 200 IJs doses on the 5th day, respectively. In the application of S. feltiae preparation, 90% mortality rate on average was observed at 200 and 400 IJs doses on the 5th day. Heterorhabditis bacteriophora preparation treatment showed the highest mean mortality rate of 75% at 400 IJs dose and on the 5th day. This study is an acceptable step in determining the possibilities of using EPNs in the control of S. littoralis.