EVALUATION OF FUNGICIDES FOR CONTROL OF ALTERNARIA BROWN SPOT AND CITRUS SCAB

TIMMER, L. W.

Abstract


From 1991-96, registered and experimental fungicides were evaluated for control of Alternaria brown spot caused by Alternaria alternata pv. citri and citrus scab caused by Elsinoe fawcettii. In most cases, three fungicide applications were made to susceptible tangerines or tangerine hybrids from March to May and fruit was evaluated at harvest for disease severity and percentage of marketable fruit. Iprodione (Rovral), captafol (Difolatan), chlorothalonil (Bravo), azoxystrobin and copper fungicides provided control of Alternaria brown spot. Neem oil (Trilogy) was effective in some tests, but not in others. Tebuconazole (Folicur), fosetyl-Al (Aliette), propiconazole (Tilt), captan, thiophanate-methyl, and benomyl (Benlate) were ineffective against Alternaria brown spot. Benomyl, ferbam (Carbamate), fluazinam, fenbuconazole, tebuconazole, thiophanate-methyl + ziram, kresoxim-methyl, and copper fungicides all reduced the severity of citrus scab. Iprodione, fosetyl-Al (Aliette), and Neem oil (Triology) were ineffective for control of this disease. A limited number of new fungicides may be registered for use on citrus in the next few years.

Keywords


alternaria alternata; elsinoe fawcettii

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Proc. Fla. State Hort. Soc.     ISSN 0886-7283