Abstract
Copper hydroxide fungicide was applied to white marsh grapefruit trees, immediately after hedging, and prior to rainfall, in experimental blocks in three groves in the Indian River area. Comparison plots did not receive copper fungicides. The copper fungicide applications were made by ground rig in an Indian River County grove as well as a Martin County grove, and by air in a St. Lucie County grove. Subsequent copper fungicide applications were made to all trees in the experimental blocks by the growers during normal production practices. Incidence of melanose, Diaporthe citri, was assessed on leaves and fruit. There was no difference in melanose lesion intensity between leaves collected from trees receiving post-hedging copper fungicide treatment and leaves from trees not receiving post-hedging copper fungicide treatment. There were fewer melanose lesions, however, on fruit harvested from trees treated with copper fungicide immediately after hedging as compared to fruit from trees not treated with copper fungicide immediately after hedging.
