Potential for the use of lactoperoxidase in postharvest disease management on fruit

We have tested the potential protection in in planta application of ions, formulated or not, and produced in tap water or in buffers (acetate, citrate or phosphate buffer) by lactoperoxidase oxidation of iodide and thiocyanate against Penicillium expansum and Botrytis cinerea infections, causal agents of respectively blue and gray mold on apples. Four independent trials against P. expansum infection revealed that ions solutions, prepared with water or buffers, are potential and reproducible alternative to synthetic fungicide in curative application, with protection rate ranged from 64 to 90%, depending on ions solution and apple's maturity. The control of gray mold with ions solutions exhibited good inhibition in three independent trials in curative application with protection rate ranged from 70 to 92%, depending on ions solution and apple's maturity. We showed that ions solutions have reduced efficacy with increase maturity of apples. Trials with formulated solutions did not presented improved performance as compared with unformulated solutions. The utilization of buffer instead of tap water to produce ions allowed the use of less concentrated ingredients with similar protection rate. We demonstrated for the first time that this soft chemical method is as efficient as a more conventional chemical method in curative application under controlled conditions.