This is one of several well-known gumming diseases of citrus. Gum formation on the trunk or branches is a characteristic symptom. Gum exudes from blisters containing gum pockets, usually located on the trunk. The wood beneath the blister shows a pink-orange color. Several factors such as freeze damage, high water table and salt accumulation contribute to the disease.
Gummosis is believed to be a condition of weak and injured trees and is reported to be infectious.
Symptoms of the disease were reproduced when healthy trees were inoculated with the fungus Diplodia natalenris . No reliable cure exists for gummosis. Keeping trees vigorously growing is the best way to avoid the problem. Rio Grande hummosis causes amber exudate to be secreted from pockets beneath the bark. Phytophthora Foot Rot Foot rot, also known as brown rot gummosis, is caused by one or more species of the fungus Phytophthora .