Pengaruh radiasi Ultraviolet-C terhadap telur Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) = Effect of ultraviolet-C radiation on eggs of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is a major pest of stored products that causes both quantitative and qualitative losses. Due to risks of insect resistance, health hazards, and environmental pollution with chemical fumigants, ultraviolet-C (UV-C) radiation has emerged as a sustainable alternative for pest management. This study investigated the effects of UV-C exposure duration on the hatchability and incubation period of T. castaneum eggs of one-, two-, and three-day-old. The experiment was arranged in a completely randomized design (CRD) and analyzed using two-way ANOVA. The treatment consisted of five irradiation durations: 0, 2, 4, 8, and 16 min, with 10 samples per treatment with five replicates. The results demonstrate that increasing UV-C exposure duration significantly reduces egg hatchability. A 16-min exposure was sufficient to achieve a 0% hatchability rate in two- and three-day-old eggs. Notably, three-day-old eggs were significantly more vulnerable, showing a drastic drop in hatchability to 4.00% after only 4 min of exposure, and reaching 0.00% hatchability at 8 min. Probit analysis confirmed this susceptibility, identifying three-day-old eggs as the most sensitive group (LT90 of 2.709 minutes), while one-day-old eggs exhibited a 33.3% higher tolerance (relative median potency) at the LT90 level. Furthermore, UV-C radiation had no statistically significant effect on the egg incubation period across all age groups, which remained at approximately 4.55 to 6 days. Morphological observations revealed brown discoloration in exposed eggs, indicating embryonic death. These findings suggest that UV-C radiation effectively suppresses T. castaneum populations by reducing egg hatchability, supporting its application in stored-product pest management.