Control of the citrus disorder called bottom box water spot

Citrus fruit rind disorders appear in many instances during postharvest handling and storage. In November of 2010 a rind disorder was observed in Clementine and Satsuma mandarins in Spain. The disorder symptomatically resembled the mandarin water spot that typically occurs in Spain associated with senescent fruit but was affecting non-senescent and still greenish ones. It appeared fundamentally in fruit to fruit contact rind areas or in fruit to harvest box contact rind areas. Incidence of the disorder was usually below 5% of the fruits. Typically the disorder appeared only in fruit treated with a drencher fungicidal treatment. We present a first characterization of this disorder called bottom box water spot. The disorder can be reduced or suppressed by using a treatment with a proprietary biostimulant formulation named the Fortisol?Ca. In industrial scale trials with 1% biostimulant controlled completely the disorder when added to a imazalil+guazatine (IMZ+GZT) drench solution and when added to a triple combination of both fungicides plus thiabendazole (TBZ) drench solution. Trials in the laboratory established the dose response for the biostimulant when counteracting the effect of the fungicidal suspensions in Lane Late, Powell and Valencia oranges; Murcott and Fortune mandarins, and Primafiori and Verna lemons. The disorder was provoked by concentrations above of the recommended either of IMZ or GZT fungicides. Except for IMZ damage on Fortune, we found a clear relationship between the dose of biostimulant added to the solution and the reduction in bottom box water spot, these relationships adjusted to polynomials equations with R2>0.90. In more practical terms we found that concentrations higher than 0.8 or 1.0% were enough to control this disorder in most of the cultivars tested.SourcesCharacterization and control of ?bottom box water spot? a new citrus rind disorder in SpainBenito Orihuel-Iranzo, Inma Navarro, Jorge Bret?, Mart?n C. MotturaDepartment of Postharvest Technology, Productos Citrosol S.A., Partida Alameda parcela C, 46721 Potries, Valencia, SpainVIII International Postharvest Symposium