Residues from Postharvest Nonrecovery Spray Applications of Imazalil to Oranges and Effects on Green Mold Caused by Penicillium digitatum. G. Eldon Brown, Florida Department of Citrus, Agricultural Research and Education Center, Lake Alfred 33850. Steven Nagy, and Matt Maraulja, Florida Department of Citrus, Agricultural Research and Education Center, Lake Alfred 33850. Plant Dis. 67:954-957. Accepted for publication 20 February 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-954.

Imazalil is an imidazole fungicide effective against green mold of citrus caused by Penicillium digitatum. A comparison of residues and efficacy was made by applying imazalil in either water or water-based resin solution wax using a nonrecovery spray application to oranges revolving on horsehair brushes saturated with the treating solutions. Applications of imazalil in water resulted in higher residues than comparable concentrations applied in water wax, and residues from water treatments were also enhanced by increased time on the brushes. Residues were not enhanced by degreening fruit with ethylene before fungicide treatment. Injured rind contained higher residues of imazalil than uninjured tissue and residues on fruit washed after imazalil treatment were reduced only slightly. Higher concentrations of imazalil were required in wax than in water applications for control of infection of posttreatment injuries and sporulation by P. digitatum.