What Are the Treatments for Bud Rot in Palm Trees?

Cause

• Bud rots in palms are often the result of infection from a couple of pathogens, namely Phytophthora palmivora and Thielaviopsis paradoxa. Bacterial infections can also lead to bud rots. Phytophthora palmivora is the more frequent cause of bud rots. The soil-borne pathogen is also referred to as P. faberi and P. theobromae. The fungus is most prevalent in palm-growing regions with high rainfall.

Symptoms

• All the causal agents of bud rots produce similar symptoms in the infected trees. Early signs include discolored and wilted spear leaves. This is followed by similar damage in the next younger leaf. Damaged spear leaves either drop or are easily pulled out. New foliage ceases to grow. The bud may remain dead for an extended period without affecting the health of older leaves. The disease kills younger palm trees entirely unless treatment is administered early.

Treatments

• It is easier to treat immature palms for the disease as compared to older trees. Bud drenches work best in younger trees as the area is easily accessible. Recommended fungicides include mefenoxam, propamocarb or fosetyl-Al. Propamocarb is only recommended for nursery use. Taller-growing mature palms are often diagnosed too late. The tree cannot be saved unless treated early. Recommended fungicides for older palms include mefenoxam or fosetyl-Al.

Preventive Measures

• Remove infected palms in advanced stages of infection immediately in order to minimize risk of infection to other trees. Avoid growing trees in overly wet or poorly drained sites to reduce susceptibility to infection. Do not use overhead irrigation and keep foliage dry on younger palms. Palm trees that are affected by cold are highly prone to bud rots. Apply preventive fungicides such as copper-based products if you anticipate cold damage to trees. These fungicides are not effective once an infection has occurred.