Evaluation of Bactericidal Chemicals for Control of Xanthomonas on Citrus. Raymond G. McGuire, Assistant Research Scientist, University of Florida, IFAS, Citrus Research and Education Center, Lake Alfred 33850. . Plant Dis. 72:1016-1020. Accepted for publication 6 June 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-1016.

Thirteen bactericidal chemicals were evaluated over three seasons on three citrus species to determine their ability to control Xanthomonas campestris pv. citri. In field trials conducted in Argentina, copper-containing products were compared with other types of bactericides and were generally superior in reducing epiphytic populations of Xanthomonas in nursery plantings of sweet orange cv. Pineapple and rough lemon and on mature grapefruit trees. Lesion numbers on leaves and fruit were also reduced with these products. Of the copper-containing chemicals, copper ammonium carbonate (Copper-Count-N) with 8% metallic copper was consistently comparable or superior in its control of Xanthomonas to other products averaging 50% copper. Agrimycin, one of seven noncopper products, was similarly effective in four of six trials in which it was tested.