Cold plasma as a dual strategy for insect control and seed quality enhancement in chickpea, lentil, and cereal by-products

Cold plasma is a sustainable, chemical-free technology for pest control and seed enhancement. This study evaluated the biological effects of dielectric barrier discharge (DBD) plasma on two stored-product pests and legume seeds. Various life stages were exposed to targeted plasma treatments: for Callosobruchus maculatus, adults and eggs were treated at 20–24 kV for 1 to 9 min, while for Tribolium castaneum, larvae, pupae and adults were exposed to 13–23 kV for 5–120 s. For T. castaneum, 100% mortality was achieved: larvae at 19 kV for 30 s, adults at 23 kV for 30 s, and pupae at 23 kV for 90 s. Mortality in other samples increased only slightly (2–5%) after 24 h, showing the effect is primarily immediate. For C. maculatus, immediate mortality exceeded 40% in all treatments and reached 100% at 24 kV for ≥ 5 min, with a > 10% increase after 24 h. Adult emergence was suppressed entirely at 24 kV for 9 min. Beyond insecticidal effects, plasma improved seed performance. In chickpea (Saeed and Mansur varieties), germination rate increased by over 20%, with seedling vigor and root/shoot growth also growing more than 20%. Lentils showed a 3% germination increase and 11–12% improvements in root and shoot length. Seed biomass increased, with fresh/dry weight gains of 12%/7% in Saeed, 25%/19% in Mansur, and ~ 6% in lentils. Water uptake rose dramatically by 75% in Saeed, 85% in Mansur, and 70% in lentils. FTIR spectra confirmed higher surface polarity (stronger O-H/N-H bands), and SEM images revealed seed coat etching and micro-cracks, explaining the improved wettability. These results demonstrate the dual functionality of cold plasma as a sustainable postharvest technology, effectively controlling pests and enhancing seed quality.