The development of precision postharvest technologies for citrus decay control

Decay control in citrus is dependent on the use of fungicides. The introduction of imazalil (IMZ) in the late 1970s increased the decay reduction efficacy of the treatments. However, higher efficacy in decay control was needed because the widespread use of ethylene degreening and the increased volumes of citrus prepacked at origin in sale units (nets, bags, gir-sacs, etc.) with up to 36 fruits. These two factors increased the claims and losses due to decay in the citrus shipments from the Mediterranean countries to the European markets. In this presentation we review the applied research breakthroughs that have allowed us to develop the “precision postharvest technologies for decay control” and we present our latest contributions in this regard. These technologies were developed after understanding the flaws that lowered the efficacy of the first treatment, applied by drenching, flooder or water tank, where the same fungicide suspension is used to treat many tons of fruit. Data obtained in the 1990s show huge variabilities in the DRIs (decay reduction indexes) because of fungi contamination of the treatment suspension and lack of proper replenishment of fungicide concentrations. At this time the problems were properly diagnosticated, however, until the release of our Zero Waste^® System in 2010, when we developed the use of our HPPA (hydrogen peroxide, peracetic acid) formulations to maintain the treatment solutions free of fungi inoculum and characterized the decrease in the fungicide concentrations in the suspensions, it was almost impossible to solve the problems mentioned and achieve high and constant efficacies in decay control. In the last years we have developed the Easy Kit^® to monitor the fungicide concentrations, and we will present our new Automatic Treatment Control System. With this system we can measure and control automatically the concentrations of several fungicides, potassium sorbate and PAA in the drenchers, flooders and water tanks.