Background: Pesticide residue and its poor utilization remains problematic in agricultural development. To address the issue, a nano-pesticide has been developed by incorporating pesticide acetamiprid in porous silica nanoparticles. Results: This nano-pesticide had an acetamiprid loading content of 354.01 mg g⁻¹. Testing LC₅₀ value against tea aphids of the commercial preparation was three times that of the nano-pesticide. In tea seedlings (Camellia sinensis L.), acetamiprid was transported upward from the stem to the young leaves. On day 30, the average retained concentrations in tea leaves treated with the commercial preparation were about 1.3 times of that in the nano-pesticide preparation. The residual concentrations of dimethyl-acetamiprid in leaves for plants treated with the commercial preparation were about 1.1 times of that in the nano-pesticide preparation. Untargeted metabolomics of by LC–MS on the young leaves of tea seedlings under nano-pesticide and commercial pesticide treatments showed significant numbers of differentially expressed metabolites (P < 0.05 and VIP > 1). Between the nano-pesticide treatment group and the commercial preparation treatment group there were 196 differentially expressed metabolites 2 h after treatment, 200 (7^th day), 207 (21^st day), and 201 (30^th day) in negative ion mode, and 294 (2^nd h), 356 (7^th day), and 286 (30^th day) in positive ion mode. Preliminary identification showed that the major differentially expressed metabolites were glutamic acid, salicylic acid, p-coumaric acid, ribonic acid, glutamine, naringenin diglucoside, sanguiin H4, PG (34:2) and epiafzelechin. Conclusions: This work demonstrated that our nano-pesticide outperformed the conventional pesticide acetamiprid in terms of insecticidal activity and pesticide residue, and the absorption, transportation and metabolism of nano-pesticide in tea plant were different, which pave a new pathway for pest control in agricultural sector. Graphical

This study investigated the effect of formula water based on soda water and HCO₃⁻ on the sensory evaluation and substances of different teas. Highly fermented teas showed better sensory quality with a higher soda water ratio in the formula, while low-fermented teas improved with a small amount of soda water. Low HCO₃⁻ (≤21.97 mg/L) enhanced aroma and reduced bitterness, whereas high HCO₃⁻ (≥40.27 mg/L) can dim the brightness of tea infusion, dull the aroma, and reduce refreshing taste. High HCO₃⁻ is unfavorable to green tea’s substance stability but somewhat beneficial to that of black tea. When brewing tea with TBW (tea brewing water), a longer brewing time yields more substances dissolved by HCO₃⁻. Compared to four waters, TBW was better for green and black teas. In short, multiple brews with TBW were best. This study provides a reference for the optimization of the quality of tea brewing water.