Control and prevention of contact infection of brown rot disease with fosetyl‐aluminium, and residue levels in post‐harvest‐treated citrus fruits

Abstract

AbstractThe effect of fosetyl‐aluminium on the control and spread of brown rot disease Phytophthora citrophthora in post‐harvest citrus fruit was studied in laboratory and semi‐commercial experiments. Aqueous solutions of fosetyl‐aluminium at 5 to 10 g a.i. litre−1 controlled the fungus even when applied 3 days after inoculation at 17°C. No mycelia developed on the peel surface of treated fruit. The fungicide exerted a good prophylactic effect on healthy fruit, protecting them during storage from contact inoculation. Fosetyl‐aluminium also showed a fungitoxic effect in vitro and in vivo on other fungi which developed in harvested citrus fruits. Residue levels of phosphoric acid in the treated fruit were higher when the fungicide was incorporated in the wax coating the fruit than when applied in aqueous solution, and levels were lower in the pulp than in the peel. It is concluded that fosetyl‐aluminium is a suitable commercial post‐harvest treatment for control of brown rot in citrus fruits.