Investigation of viral pathogens of heliothis (Cottonbollworm) (Lepidoptera: Noctuidae) species

The cotton bollworm (Helicoverpa/Heliothis sp., Lepidoptera: Noctuidae) species are found cosmopolitan all over the world. In this thesis study, aimed to develop a microbial biocontrol system for cotton bollworms, 5 nucleopolyhedrovirus (NPV) isolates were identified and their virulence were determined. The biopesticide was developed from the most effective isolate. The sizes of the inclusion bodies of the isolates were determined between 0.73 - 2.26 m, and the nucleocapsid dimensions were between 146 × 34 nm and 279 × 56 nm. In phylogenetic analysis, it was observed that the isolates were more close to the Helicoverpa armigera NPV (HearNPV) Chinese isolate. As a result of biotests, over 80% mortality with HearNPV-TR isolate was determined against all species. The genome of the HearNPV-TR, which was decided to be developed as a biopesticide, was found to be 130,691 base pairs. The homologous repeat regions (hr3 and hr5) and baculovirus repeat genes (bro-a) in the genome were found to be different than Helicoverpa/Heliothis NPV genomes in the literature. LC50 value of the HearNPV-TR formulation on third instar H. armigera larvae was calculated as 1.9 × 104. In this study, baculovirus isolations from Helicoverpa/Heliothis species in our country were performed, they were identified in detail and a microbial insecticide was developed from HearNPV-TR isolate for the control of Helicoverpa/Heliothis species. Key words: Cotton bollworm, baculovirus, biopesticide, oil formulation, genome analysis