Antifungal activity of sodium propylparaben alone or in combination with low doses of imazalil against Penicillium decay on citrus fruit

The performance of postharvest treatments with sodium propylparaben (SPP), alone or combined with low doses of the fungicide imazalil (IMZ), against citrus green (GM) and blue (BM) molds was evaluated on several citrus species and cultivars artificially inoculated with Penicillium digitatum and P. italicum, respectively, and incubated at 20 °C or cold-stored at 5 °C. Effectiveness of 100 mM SPP dips at 20 °C for 60 s was higher on oranges than on mandarins, with GM and BM incidence reductions of up to 60–90 % after 7 days at 20 °C. Irrespective of citrus cultivar and storage condition, SPP generally improved the curative action of 25 μl l^?1 IMZ to control Penicillium molds. In additional tests, 100 mM SPP dips at 20 °C for 60 s only prevented GM on ‘Valencia’ oranges inoculated 24 h after treatment when combined with IMZ. It can be concluded that postharvest SPP treatments show promise as an effective alternative to be considered in citrus postharvest disease control programs.