Hurricane Recovery

Disease

Disease: Disease problems will increase in some groves affected by hurricanes  Probably the biggest risk is for brown rot  epidemics.  Fallen fruit becomes readily colonized with Phytophthora which produces spores on the surface.   With rains that follow, spores can be dispersed and infect remaining fruit in the tree.  Where groves have a history of brown rot or where brown rot appears, sprays of copper or phosphorous acid products can be used to control Phytophthora brown rot.  Other disease problems which may occur are not as urgent.  Damaged twigs will be quickly colonized by Phomopsis , the fungus that causes Melanose.  Abundant spores likely will be produced next spring.  Additional fungicide sprays may be needed for production of fresh market grapefruit next year.  Since all of the leaf litter from last winter and spring has decomposed or has been blown away, spore production of the greasy spot fungus is very low.  Thus, sprays to protect new foliage being produced after the hurricane are probably not essential.  Limb breakage can result in rather large wounds on trunks and scaffold branches.  Eventually wood-rotting fungi will invade and rot heartwood.  This damage will probably shorten tree life or weaken limbs predisposing them to further wind damage.  That may be a problem long-term, but there is little that can be done.  Wound paints are only effective short-term and will not greatly affect tree longevity. New cases of wind blown canker have been documented on new regrowth after hurricanes.

More information:

Florida Citrus Pest Management Guide