Palmetto Weevil

The Palmetto Weevil (PW, Rhynchophorus cruentatus) is native to Florida and is the largest known weevil in North America. Adults can be up to 1 ¼” in length. Distressed palm trees are most vulnerable to this damaging insect which makes transplanted and environmentally-stressed palms more susceptible to attack. Any stress factors such as drought, excessive moisture, cold damage, lightning strikes, fire and nutrient deficiencies can cause palms to be at risk.

After mating the PW female deposits her eggs at the base of the palm. The larvae (grub worms) then feed into the trunk causing severe vascular damage over time that eventually results in death of the infested palm. The grubs will then pupate into adult weevils and repeat the cycle. The life cycle from egg to adult is approximately 84 days which results in long feeding periods.

Common Symptoms

Many types of palm trees are susceptible to Palmetto Weevil including: Canary Island Date, Bismarkia, Sabal, Coconut, Washingtonia, Latan, Royal, Phoenix dactylifera, Fan and Florida Thatch. The symptoms of a PW infestation generally involve an often irreversible decline of younger leaves. In the early stages of infestation, the older, upright leaves will begin to droop but then quickly collapse thereafter. As the infestation progresses, the larval feeding damage and associated rot is so severe that the integrity of the crown is compromised and the top of the palm falls over. If the palm is pulled apart at this stage, larvae, cocoons, and even adults may be found within the crown region. Early detection of weevil infestation is difficult, and treatment even in the early stages of infestation may be too late to save the tree depending upon the amount of damage to the apical meristem.

Treatments

Trunk injection of IMA-jet® (Imidacloprid) or TREE-äge (emamectin benzoate) will give both preventative and curative control providing there has not been extensive feeding damage to the palm. It is also recommended to apply PHOSPHO-jet™ to help control any secondary disease pathogens and PALM-jet Mg™ to provide needed nutrients for overall plant health and vigor.