Induction of defense mechanisms in avocado using Mexican oregano oil-based antifungal sachet

Active sachets can be used to manage postharvest losses associated with phytopathogens in fruit and vegetables. Diseases associated with phytopathogens are the principal causes of avocado losses postharvest. This study was performed to develop antifungal active sachet-based oregano oil microencapsulated with starch/agave fructans that allows in vivo and in vitro control of phytopathogens associated with avocado decay. In addition, avocado-sachet interactions were studied. Oregano oil sachets inhibited 100% of the in vitro growth of Colletotrichum gloeosporioides, Colletotrichum acutatum, Diaporthe passiflorae, and Neoscytalidium hyalinum at 30 °C for 12 d The efficacy of the oregano oil sachets was confirmed on avocados inoculated with C. gloeosporioides. Active sachets reduced the injury area of anthracnose infection in avocado without negative effects on the color or firmness of the fruit, compared to untreated control. Treatment also caused significantly higher (p < 0.05) phenylalanine ammonia-lyase, chitinase, β-1,3-glucanase, catalase and peroxidase activities compared to the control fruit. In addition, antifungal sachets significantly enhanced the contents of total flavonoids and phenolic compounds in treated avocados.