Evaluation of Fungicides to Control Citrus Black Spot on ‘Valencia’ Caused by Guignardia citricarpain South Florida

P D Roberts, K E M Hendricks, C Brooks, H Younce


A field trial to evaluate the efficacy of fungicides and timing of spray regimes to control the recently introduced fungus, Guignardia citricarpa, causing citrus black spot (CBS) was initiated. The trial was established at a commercial site in a block of ‘Valencia’ that was identified with CBS in 2011. Fifteen treatments including ten products were applied at intervals starting after fruit harvest and continuing through September. Ratings on the number of the symptomatic fruit on the tree and the number of dropped fruit with symptoms were taken in Dec. 2011 and Feb. and Mar. 2012. In general, most of the data from fungicidal regimes were not statistically different from the untreated plants in preventing symptoms of CBS. Additional field trials are needed to more fully investigate timing of applications and products for efficacy in suppression of this disease.


exotic disease, fungus, disease management

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