There are many pathogens that can cause bud rot of palm trees. Some of the common causes are Phytophthora palmivora, Thielaviopsis paradoxa and bacteria. Regardless of the pathogen causing the disease, the symptoms and treatment are the same.
When a palm tree initially gets infected with bud rot, the first symptoms that become visible are: discoloration and wilting of the spear (new main) leaf and wilting and discoloration of the newer fronds (leaves). The yellowing and wilting is normally from the inner part of the leaf, outwards. In severe cases of disease the main frond or spear leaf can be easily pulled from the bud. In tall palms, where the terminal bud (top point where new growth emerges) cannot be seen from the ground, the early symptoms of palm bud rot are often missed. Often the disease onset is not noticed until new frond growth has stopped and the crown begins to appear to be shrinking or loses its top and appears flat. In cases such as this, often the terminal bud has died, and no new fronds are produced. Existing fronds will remain green for a few months as the tree slowly dies.
Palm bud rot caused by bacterial infections is often associated with cold damage and stress placed on the tree by exposure to cold temperatures. When a palm tree is exposed to cold damage, to prevent the possible onset of palm bud rot the tree should be treated with Liquid Copper Fungicide. Immediately after cold damage the terminal bud should be sprayed, and then repeated every 10 to 14 days for a series of 4 treatments. Do not wait until palm bud rot symptoms emerge. Avoid pruning or removing cold damaged fronds, as this will place more stress on the tree and increase the potential for other bacterial or fungal infections to enter the tree.
When treating and preventing palm bud rot it is important to realize that palm trees have only one terminal bud form which all new growth emerges. Unlike most trees, such as maple and apple trees which have many points where new growth emerges, palms rely exclusively on their single terminal bud. If the terminal bud or heart becomes diseased or freezes during cold periods and dies, the tree will not be able to put out any new leaf growth and will die. That is why regular monitoring of the terminal bud and preventative care are vital to maintaining a healthy palm tree.
Recommended Steps to Treat Palm Bud Rot:
It is always best to take steps to prevent the onset of Palm Bud Rot. Preventative steps should be taken if a palm tree has experienced cold damage or palm bud rot has been identified in the local area. As a preventative treatment, spay the tree’s terminal bud with Liquid Copper Fungicide and repeat the treatment every 10 to 14 days, for 3 to 4 treatments, or as necessary.
If a palm tree is already showing symptoms of palm bud rot, immediately treat the tree with Liquid Copper Fungicide, focusing most attention towards the terminal bud. To increase the effectiveness of the spray, mix with Nature's Own Spray Helper. Repeat the spraying every 7 days as necessary. Once a tree is infected with bud rot, it usually dies, but its chances of survival can increase the earlier it is treated with liquid copper.