Spray-timing experiments for control of citrus greasy spot caused by Mycosphaerella citri were conducted in a grapefruit grove at Lake Alfred, Florida [USA], for 4 consecutive years. In all years, basic CuSO4 gave better control of greasy spot on leaves and fruit when applied in June or July, during or after peak ascospore release, than in late April or early May, before major ascospore discharge began. Benomyl controlled greasy spot as well as the Cu fungicide did prior to a shift in pathogen population from benomyl sensitive to benomyl tolerant. Greasy spot control on leaves with oil was affected little by time of spraying, and it often equaled that provided by a well-timed Cu fungicide treatment. However, unlike summer application of basic copper sulfate, oil gave variable and often no control of greasy spot rind blotch.