بررسی فلور باکتریایی لولهی گوارش لارو برگخوار پاییزه ذرت Spodoptera frugiperda (Lepidoptera, Noctuidae) بر اساس خصوصیات بیوشیمیایی و تست‌های افتراقی

Abstract
Microbial symbionts play an important role in the biology and survival of insects and are potential targets for pest control by disrupting this symbiotic relationship. The fall armyworm, Spodoptera frugiperda, which was previously considered an external quarantine pest in Iran, is being reported from some corn fields in the Orzuiye region, Kerman Province, in October 2023 for the first time. The purpose of this research is to investigate the microbial flora of the digestive tube of the fall armyworm larvae, using morphological techniques and differential tests by biochemical methods. Eggs and larvae were collected from the corn fields of Jiroft, Kerman and reared in laboratory conditions at a temperature of 27 ± 2 °C, relative humidity of 65 ± 5% and a photoperiod of 12L:12D. After colony formation, the third to fifth instar larvae were used for investigation. The contents of the digestive tube of larvae were cultured in Nutrient Agar culture medium by 16 linear method, and after purification,in special cultures, from biochemical and differential tests, Citrate, Oxidase, Urease, Catalase, Simmons Citrate agar )SCA (, Triple Sugar Iron Agar)TSI(, Methyl Red/Ves-Proskauer (MR-VP) and Mannitol Salt Agar (MSA) and Sulfur Indole Motility Media (SIM), were used.The density of bacteria was measured, and Gram staining was performed. The appearance of the colonies was examined according to certain characteristics such as size and form, color, elevation, consistency and opacity. As a result of the biochemical investigation, Escherichia coli and Salmonella, Kelebsiella, Staphylococcus and Bacillus genera were identified. Since symbiotic bacteria play an important role in insect biology, removing these symbiotic bacteria can have a negative effect on the survival and growth of the insect population.