Q: What is killing my palm trees? They are oozing at the trunk area and it smells awful. They seem to have dark, black sunken patches all over the trunk.
A: This is indeed grave news for your palms as the disease is likely Thielaviopsis Trunk Rot. The fungus causing the disease is Thielaviopsis paradoxa. It can infect any part of the palm and cause a variety of disease problems.
No palm is exempt or resistant. The end result will be the total collapse of the top of the palm onto itself or it will completely fall off. There is generally no indication of the problem in the top of the palm as the fronds remain green and intact. Only fresh trunk wounds become infected by the fungus therefore protection of the trunk prior to and at harvesting is critical. Protection during this time is difficult especially when the palms are harvested from the wild. Damage to the trunk can occur while the palm fronds (boots) are being removed from the trunk area, especially when the trunk tissue is damaged by cutting or ripping into the trunk flesh. Transporting palms from one site to another can also result in injury to the trunk but damage can also occur when transplanting at the site. It might be helpful to apply a fungicide to the palm at the time of harvest but that would be long before you, the homeowner, receive the palm. Once the disease is in the trunk tissue the vascular system is compromised and the palm will begin its inevitable decline. No chemical control will be effective in curing the disease; our only management tool is prevention.
I am sorry to tell you the palms must be removed and destroyed. Do not use the ground stump material for mulch. There is some good news; Thielaviopsis disease is confined to the vascular tissue only and not soil born. This means another palm can be put back in the same place without fear of the disease being transmitted from palm to palm. Thielaviopsis is unlike Ganoderma in that aspect. Remember, palms with Ganoderma Butt Rot must be removed and no palm should go back in the same site as this fungus lives in the soil and will be transmitted to the new palm.