Tip Rot on Plumeria

Symptoms

• Long believed to be a fungus, horticulturists at the Plumeria Society of America now think that black tip fungus, or black tip rot, is caused by a bacteria. Although it often appears in the spring, after frost damage, it can appear at any time of the year, causing the growing point to turn black and stopping any further growth from occurring. Once the temperatures warm up, the black tips will grow hard and break off, and your plumeria will produce new branches. Black tip isn’t usually fatal to the plant.

Prevention

• Low spring temperatures and high humidity encourage outbreaks of black tip. Plumerias suffering from stress are more likely to succumb to this disease. Keep shrubs from becoming stressed by avoiding temperature swings and by keeping them warm during cold weather. Provide plumerias with a lot of sun. Use a seaweed extract liquid fertilizer as soon as new growth appears in the spring, and apply it as a foliar spray before black tip symptoms appear. Repeat once a week until early summer.

Treatment

• Remove tips by trimming black areas away until you see white wood. Maintain temperatures of at least 60 degrees Fahrenheit. Provide plumerias with a good draining mix and cut back on water. Reduce humidity and run a fan 24 hours. Provide 24-hour lighting to keep shrubs from entering dormancy.

Winter Care

• Initiate winter dormancy by removing all leaves late in the fall. Snip the leaf petioles about one inch from the trunk. Keep your plumeria in the basement or in a cool room with the temperature above 40 degrees. Don’t place pots on concrete floors because the cold concrete can lead to root damage. Your plant won’t require light during the winter. Overwatering during dormancy can lead to root rot. Provide one cup of water every month to keep the stems from drying out but don't water otherwise. Don’t put your plant back outside in the spring until the nighttime and daytime temperatures average 65 degrees.