An orange showing signs of "citrus greening" this spring in Fort Pierce, Fla. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

Ripening fruit in a grove in Plant City, Fla., this month. Florida citrus growers are worried about citrus greening, which causes bacteria to grow on the leaf and fruit, eventually killing the tree. Chris O'Meara/AP hide caption

itoggle caption Chris O'Meara/AP

Oranges ripen in a Plant City, Fla., grove on Wednesday. Growers in Florida, Texas and California are worried about citrus greening, a disease that makes the fruit bitter and unmarketable. Chris O'Meara/AP hide caption

itoggle caption Chris O'Meara/AP