Suppression of Apple Bloom by Fungicides That Inhibit Sterol Synthesis. A. J. Latham, Department of Botany, Plant Pathology, and Microbiology, Alabama Agricultural Experiment Station, Auburn University 36849. W. A. Dozier, Jr., and J. W. Knowles, Department of Horticulture, Alabama Agricultural Experiment Station, Auburn University 36849; and M. H. Hollingsworth, North Alabama Horticulture Substation, Cullman 35055. Plant Dis. 69:776-778. Accepted for publication 5 May 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-776.

The proportion of spurs blooming on Redspur Delicious apples in 1983 was significantly lower after season-long applications in 1982 of bitertanol and etaconazole (fungicides that inhibit biosynthesis of ergosterols) and some fenarimol-captan treatments than with benomyl and carbamate fungicides. Return bloom in 1984 was significantly less after season-long applications of bitertanol or etaconazole than after benomyl, suggesting detrimental effects to apple buds by the former fungicides. Return bloom in 1984 from trees not sprayed during 1983 was positively correlated with leaf numbers at harvest in 1983. Trees partly defoliated by scab caused by Venturia inaequalis showed less return bloom in 1984.