Investigation of the developmental biology of Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg induced Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and evaluation of the antimicrobial activity of its hemolymph

In this thesis, the developmental biology of the storage pest, the Mediterranean flour moth Ephestia kuehniella (Lepidoptera: Pyralidae), and the antimicrobial response elicited in its hemolymph were examined under infection with a Fusarium proliferatum strain. The main objective was to assess how fungi that can be used in biological control affect the host and to elucidate the physiological responses triggered within the host organism. A flour-moth colony was first reared under controlled laboratory conditions on an artificial diet with standardized nutrient content; conidial suspensions prepared from 14-day-old fungal cultures were then applied to larvae at various doses. Before inoculation, optimal culture conditions for the fungus growth medium, temperature, and pH were established to maximize conidial viability. After infection, biological parameters—including cocoon-spinning time, pupation time, pupal period, total pre-adult development duration, adult longevity, adult weight, and total egg production were recorded daily from larvae to adults and compared with an uninfected control group. The infection caused statistically significant delays and weight losses across all developmental parameters. Hemolymph samples taken at the fourth larval instar were evaluated using disk-diffusion assays; enlarged inhibition zones against Staphylococcus aureus and Klebsiella pneumoniae indicated that infection stimulated the host's immune system, leading to increased antimicrobial activity in the hemolymph. Overall, the data show that F. proliferatum infection both slows the pest's development and enhances antibacterial defenses in the host, supporting the potential of this fungus–insect interaction as a viable component of integrated pest management strategies.