Citral

In May 2021 (kiwifruit flowering period determined using the BBCH-scale), leaves of Actinidia deliciosa ‘Guichang’ visibly affected by leaf spot disease were collected from Xifeng County (27°2′ N, 106°30′ E). The leaves were disinfected with 75% alcohol for 30 s, rinsed with sterile water three times, and dried with sterile paper. The diseased tissue was then cut into 1 cm² pieces, placed in potato dextrose agar (PDA: 200.0 g potato, 20.0 g glucose, 17.0 g agar/L) plates, and cultured at a constant temperature of 28 °C and 75% relative humidity for 5 d. A single colony was selected and transferred to new PDA plates until the mycelia were identical in colour and shape. The pure culture obtained was stored in 25% (volume/volume) glycerol at −80 °C for long-term storage. The natural antifungal agents (osthole, cinnamaldehyde, resveratrol, allicin, honokiol, citral, and carvacrol) used with purities of ≥98% were provided by Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China) and stored at 4 °C.

Chitosan (CS, deacetylation degree ≥ 99%) and KBr were purchased from Sigma-Aldrich Co. Ltd. (Shanghai, China). Cinnamaldehyde (CA, purity ≥ 99.9%), benzaldehyde (BZ, purity ≥ 99.9%), vanillin (VL, purity ≥ 99.9%), citral (CT, purity ≥ 99.9%), and citronellal (CN, purity ≥ 99.9%) were the product of Macklin Inc. (Shanghai, China). Staphylococcus aureus (S. aureus) (ATCC65389) was the product of Guangdong Institute of Microbiology (Guangzhou, China). The LB Broth was purchased from Guangdong Huankai Microbial SCI&TECH Co. Ltd. (Guangzhou, China). Other unmentioned chemicals were analytically pure.

Sodium alginate (from brown algae, low viscosity) and Pluronic F-127 (F-127) were obtained from Sigma-Aldrich (Saint Louis, Missouri, America). D-(+)-Gluconic acid δ-lactone (GDL) and ethylenediaminetetraacetic acid disodium salt (disodium–EDTA) were purchased from Aladdin (Shanghai, China). Citral (97%) was gained from Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China). Calcium chloride anhydrous, sodium hydroxide, Sudan III (bioreagent), acetic acid, isooctane, potassium iodide, sodium thiosulfate, starch, and 2, 2, 4-trimethylpentane were acquired from Kelong Chemical Reagent Factory (Chengdu, China). Polyglycerol polyricinoleate (PGPR 90) was purchased from Danisco (Kunshan, China). Soybean oil (SO) was provided by Sichuan Jiali Grain and Oil Co., Ltd. (Chengdu, China). Benzyl benzoate (BB) was purchased from Sinopharm Chemical Regent Co., Ltd. (Shanghai, China). Cylindrical capillary tubes and square capillary were obtained from VitroCom (New York, NY, American). Deionized (DI) water from a water purification machine (Ulupure, Sichuan ULUPURE Ultrapure Technology Co.,Ltd., Chengdu, China) was employed in the experiments. All the reagents were of analytical grade and used as received unless otherwise stated.