Gliocladium  or Pink Rot

A Fact Sheet prepared by Dr. Henry Donselman, Palm Specialist

Gliocladium  or Pink Rot:  Pink Rot  is an invasive secondary disease that attacks the bud tissues, petioles, leaf blades, and trunks.  It almost always occurs in palms that are under stress and enters via wounds or areas damaged by such causes as the removal of leaves and sunburn,  This pathogen readily produces dusty masses of orange to pink to white conidia (spores).  In severe infections, stems may die or the palms may be rendered unusable because of their appearance.  It also can invade the soft newly developed trunk tissue under the petiole.  Rarely it will cause cankers in the trunk.  It is often very troublesome on interiorscape palms where there is little air movement.

Pink Rot is windborne and prefers cool, humid climates.  Often it is seen in the Winter, and then disappears in the summer.  Palms that are known to be highly susceptible under optimum disease conditions are:  Queen Palms, the Majesty Palm (Ravanea rivularis), Phoenix sp., and Kentia Palms.  Many other palms can also be infected, particularly if they are stressed.

There is no good chemical control of this disease although some have indicated that Cleary's 3336 applied to the affected areas (with a spreader sticker) has some activity.  My research indicates that one of the most frequently infected sites are the wounds caused by ripping or tearing old leafbases from the trunk.  One needs to carefully cut the leaves with a sharp sterile object slightly above the point of attachment.  The remaining portion will brown and naturally fall-off in a short period of time.

Dr. Alan Meerow provides the following from Betrock's Guide to the Landscape Palms. (YOU SHOULD BUY THIS BOOK)

"Pink rot or Gliocladium blight. This fungal disease is a serious problem on Chamaedorea species and areca palms in Florida, and kentias, majesty, queen, date and the native Washingtonia filifera palms in California. The causal agent is not active at temperatures above 85° F, thus it is primarily a winter disease in Florida, while remaining active most of the year in coastal California. Oozing lesions occur on the stems, and leaves turn brown and droop. The fungus produces salmon-pink, powdery fruiting bodies. The disease is easily spread if affected leaves are pulled off the plant prematurely.  Scotts FungoFlo and Mancozeb fungicides provide good control."