Screening Of Citrus Postharvest Fungicide And Study On Antiseptic Preservation

Citrus fruits contain large amount of biological active substances with high production.Postharvest infectious disease is one of the main causes of postharvest decay on citrus.Because of the long-term use of chemical fungicides,pathogens have resistance to common fungicides,and their efficacy drops seriously.In order to improve the sterilizing effect of chemical fungicides,in this study Penicillium italicum is taken as the object of the main pathogen of citrus fruit postharvest rot,using 21 kinds of 5,7-two hydroxy flavones compounds and chemical fungicides prochloraz and carbendazim combination were screened the obvious effect of two flavonoids and fungicide compound and determine the best combination of inhibiting Penicillium italicum in citrus.On this basis,in vitro and in vivo experiments were conducted to evaluate the effect of complex fungicides on citrus blue mold,and further study the effect of complex fungicides on citrus fruit disease resistance.The main results are as follows:(1)By studying the two common fungicides carbendazim,prochloraz with 21 kinds of 5,7-2 hydroxy flavones synergies,the results showed that the complex fungicides of carbendazim and galangin,carbendazim and chrysin,prochloraz and pinocembrin,prochloraz and galangin had the best inhibitory effect.(2)The concentration of carbendazim in the complex fungicides of carbendazim and galangin was 68.92 mg/L,and the concentration of galangin was 3.85 g/L.The concentration of prochloraz in the complex fungicides of prochloraz and pinocembrin was223.2 ?g/L,and the concentration of pinocembrin was 1.494 g/L.The concentration of prochloraz in the complex fungicides of prochloraz and galangin was 111.6 ?g/L,and the concentration of galangin was 3.85 g/L.(3)Fungus spots experiment showed the inhibitory rate of three kinds of complex fungicides of carbendazim and galangin,prochloraz and pinocembrin,and prochloraz and galangin on the Penicillium italicum spot cultured 3 days were respectively 70.58 %,61.07 %,46.65 %.(4)Three kinds of complex fungicides of carbendazim and galangin,prochloraz and pinocembrin,and prochloraz and galangin have certain effects on the prevention and control of citrus inoculated with Penicillium italicum.During the storage,fungal spots treated by the complex fungicides were smaller than those in the blank control at the same time.(5)The treatment of the complex fungicides increased the content of flavonoids and phenols,and improved the activity of PPO,POD and PAL which were closely related to the induction of disease resistance in citrus peel.Therefore,the complex fungicide has a certain development prospect.