Development of Densovirus-Based Bioinsecticide (Tenebriokiller) for Use in the Control of Mealworm, Tenebrio Molitor L., 1758 (Coleoptera: Tenebrionidae)

Abstract

TenebriomolitorL., 1758 (Coleoptera: Tenebrionidae) is one of the major storage pests affecting a large proportion of pasta, flour, starch, and rice. Densoviruses are biocontrol agents with a single-stranded DNA genome that is enveloped and very small in size. In this study, crude TmDNV-TR was formulated using bovine gelatin, and the formulation called Tenebriokiller was prepared in T & uuml;rkiye. The dose of virus in the formulation was determined to be 2.8x108 copies/mL-1. Five different doses were used (2.8x108, 2.8x107, 2.8x106, 2.8x105, and 2.8x104 copies/mL-1) against 10th instar T. molitor larvae. The mortality was detected 100% (LD50: 4 x106 copies/mL-1, LT50: 6 day, LD95: 2.2 x108 copies/mL-1 and LT95: 9 day) by day 14. The stability of the crude virus and Tenebriokiller was tested at different storage temperatures (4 and 25 degrees C) over various periods (3 and 6 months). Accordingly, the mortality rate of the fresh formulation was 100% as in the previous step, while at 4 degrees C the mortality rate at the end of 3 and 6 months remained 100%, and at 25 degrees C, the mortality rate at the end of 3 and 6 months was 98% and 95% respectively, at the end of day 14. Preliminary pathogenicity tests in the laboratory showed that the virus was highly lethal to the target organism. The virus was therefore formulated to maintain its stability during storage, and a prototype formulation was developed.