Molecular Diagnosis of the Corn Stem Borer <i>Sesamia cretica</i> Led. and Evaluation of the Efficacy of Some Fungi with the Chemical Insecticide Ethephon on the Biological Aspects of the Insect under Laboratory Conditions

Abstract A laboratory experiment was conducted at the Plant Protection Department Laboratory, College of Agriculture, University of Tikrit, to evaluate the efficacy of two fungal isolates, Aspergillus versicolor isolate Has-3 and Fusarium cf . incarnatum - equiseti isolate Has-4, plant growth regulator (Cobon) Ethephon 480 SL, the insecticides Belt 480 EC, Denim Fit UV 45 WG and Movento 100 SC were used to assess their effects on some biological aspects of third-instar larvae and pupae of the corn stem borer S . cretica . The study included the molecular diagnosis of the corn stem borer, which was recorded as Sesamia cretica isolate Has-7 with the accession number OR758844.1 in the global genetic bank (NCBI). Regarding the role of the study factors, most of the treatments showed a significant effect on the percentage of transformation of S . cretica larvae into pupae then into adults. Additionally, the resulting adults exhibited high rates of deformities that prevented them from feeding, flying, and performing essential physiological processes, leading to the insect’s death shortly after transformation. Ethephon showed a clear reduction in the percentage of transformed insects at 62.5 and 125 ml/100 liters of water, with the percentage of larvae transforming into pupae 23.33% and 20.00%, and pupae into adults 46.66% and 36.66%, respectively. The percentage decreased from 100% in the control treatment to 3.51% for transformed larvae and 16.10% for transformed pupae into adults when using Denim Fit, with a significant difference compared to the insecticides Belt and Movento.