Efficacy of Guazatine and Iminoctadine for Control of Postharvest Decays of Oranges. G. Eldon Brown, Florida Department of Citrus, Scientific Research Department, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred 33850. . Plant Dis. 72:906-908. Accepted for publication 28 June 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0906.

Guazatine is a random mixture of guanidated 1,8-diaminooctane and its higher oligomers, including dioctamethylenetriamine and trioctamethylenetetramine, while iminoctadine consists only of dioctamethylenetriamine. Iminoctadine was equal to or significantly better than guazatine in numerous tests to evaluate control of stem end rot caused by Diplodia natalensis and Phomopsis citri, green mold caused by Penicillium digitatum, and sour rot caused by Geotrichum candidum. Iminoctadine, unlike guazatine, controlled sporulation of P. digitatum, and spread of G. candidum during storage. All citrus decay pathogens, when tested in vitro, were more sensitive to iminoctadine than to guazatine. In comparisons with other fungicides, these two fungicides were less effective than benomyl for control of stem end rot, but were comparable to etaconazole for sour rot control and to imazalil and thiabendazole for control of green mold. Iminoctadine was comparable to imazalil for controlling soilage caused by P. digitatum.

Keyword(s): Citrus sinensis, fungicides, postharvest pathology.