|ZHONG, TIAN - University Of Florida|
|ZHANG, JIUXU - University Of Florida|
|KOU, JINGJING - University Of Florida|
|ZHANG, ZHIKE - University Of Florida|
|RITENOUT, MARK - University Of Florida|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2021
Publication Date: N/A
Interpretive Summary: Stem-end rot caused by Lasiodiplodia theobromae is one of the most common postharvest decays on citrus fruit produced in Florida which often causes a significant impact on the quality, marketing values and economic returns of fresh citrus. the ClO2 gas treatments reported here appear promising to reduce L. theobromaeon decay in citrus fruit without causing adverse effects. The antifungal activity against L. theobromae was demostrated in both in vitro and in vivo experiments. In addition, these ClO2 treatments resulted in no negative effects on fruit quality, and in some cases reduced the decline in TA during storage. This study suggests that ClO2 gas and new application technologies have great potential for development as an effective component of a decay control system to reduce fruit losses, maintain quality, and prolong shelf life.
Technical Abstract: The focus of this study was to develop applicable technologies using chlorine dioxide (ClO2) gas to control postharvest stem-end rot caused by Lasiodiplodia theobromae on citrus. Experiments of both in vitro and in vivo were conducted. Mycelial growth of L. theobromae on potato dextrose agar (PDA) plugs was completely inhibited by a 24-h ClO2 exposure provided by 0.5 g of ClO2 generation medias in a 7.7-L sealed container. In vivo experiments were conducted by using artificially inoculated ‘Tango’ mandarins and naturally inoculated ‘US Early Pride’ mandarins. When incubation time was 0-6 h after artificial inoculation, the inoculated fungus was easily suppressed or killed by ClO2 and the higher efficacy was found at higher ClO2 doses. On the other hand, 12-24 h incubation after inoculation made the fungus more difficult to be inhibited or killed by ClO2 exposure. When naturally infected c fruit were used, the decay incidences on ClO2 treated fruit (6 and 9 g of ClO2 media per box) were reduced by 22.8 to 23.8% compared to controls. In addition, the ClO2 treatments resulted in no significant effects on citrus fruit quality properties such as weight loss, texture profiles, total soluble solid (TSS) content and titratable acid (TA). The results obtained from this study indicate that ClO2 gas has great potential to be developed as a component of the integrated citrus postharvest decay control system to maximally reduce fruit losses due to decays.